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Suggested Citation:"5 Physics Laboratory." National Research Council. 2002. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories: Fiscal Year 2002. Washington, DC: The National Academies Press. doi: 10.17226/10510.
×

5
Physics Laboratory

Suggested Citation:"5 Physics Laboratory." National Research Council. 2002. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories: Fiscal Year 2002. Washington, DC: The National Academies Press. doi: 10.17226/10510.
×

PANEL MEMBERS

Janet S. Fender, Air Force Research Laboratory, Chair

Duncan T. Moore, University of Rochester, Vice Chair

Patricia A. Baisden, Lawrence Livermore National Laboratory

Anthony J. Berejka, Consultant, Huntington, New York

John H. Bruning, Corning Tropel Corporation

John F. Dicello, Johns Hopkins University

Jay M. Eastman, Lucid, Inc.

Stephen D. Fantone, Optikos Corporation

Thomas F. Gallagher, University of Virginia

R. Michael Garvey, Datum Timing, Test and Measurement, Inc.

Lene Vestergaard Hau, Harvard University

Tony F. Heinz, Columbia University

Jan F. Herbst, General Motors Research and Development Center

Franz J. Himpsel, University of Wisconsin

David S. Leckrone, Goddard Space Flight Center, NASA

Dennis M. Mills, Argonne National Laboratory

James M. Palmer, University of Arizona

William N. Partlo, Cymer, Inc.

Thad G. Walker, University of Wisconsin-Madison

Frank W. Wise, Cornell University

Submitted for the panel by its Chair, Janet S. Fender, and its Vice Chair, Duncan T. Moore, this assessment of the fiscal year 2002 activities of the Physics Laboratory is based on site visits by individual panel members, a formal meeting of the panel on February 20-21, 2002, in Boulder, Colorado, and documents provided by the laboratory.1

1  

U.S. Department of Commerce, Technology Administration, National Institute of Standards and Technology, Physics Laboratory: Technical Activities 2001, NISTIR 6838, National Institute of Standards and Technology, Gaithersburg, Md., January 2002, and U.S. Department of Commerce, Technology Administration, National Institute of Standards and Technology, Physics Laboratory: Annual Report 2001, National Institute of Standards and Technology, Gaithersburg, Md., January 2002.

Suggested Citation:"5 Physics Laboratory." National Research Council. 2002. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories: Fiscal Year 2002. Washington, DC: The National Academies Press. doi: 10.17226/10510.
×

LABORATORY-LEVEL REVIEW

Technical Merit

The Physics Laboratory states its mission as supporting U.S. industry by providing measurement services and research for electronic, optical, and radiation technologies. It is organized in six divisions (see Figure 5.1): Electron and Optical Physics Division, Atomic Physics Division, Optical Technology Division, Ionizing Radiation Division, Time and Frequency Division, and Quantum Physics Division (JILA). The first five divisions are reviewed below under Divisional Reviews; the Quantum Physics Division is reviewed as part of the subpanel report on JILA found at the end of this chapter.

The NIST Physics Laboratory has long been known among its technical peers for the outstanding level of scientific research that it produces. The laboratory has a tradition of world leadership in many of its areas of activity. Overall, its researchers are well known for the originality of their work, their

FIGURE 5.1 Organizational structure of the Physics Laboratory. Listed under each division except Quantum Physics (JILA) are the division’s groups.

Suggested Citation:"5 Physics Laboratory." National Research Council. 2002. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories: Fiscal Year 2002. Washington, DC: The National Academies Press. doi: 10.17226/10510.
×

ability to carry out difficult measurements to record levels of precision, and their deep understanding of the basic physical phenomena that underlie such measurements.

In its current assessment, the panel found that this technical tradition continues throughout the laboratory. The panel continues to be impressed with the quality and the quantity of top-notch scientific results that the laboratory produces. The awarding of the Nobel Prize for Physics to a laboratory researcher (Eric Cornell) for the second time in 5 years is the most obvious indicator of the quality of this work. Throughout the laboratory, researchers have an impressive record of publication in leading peer-reviewed scientific journals, of presentations at leading technical conferences, and of invited talks at leading conferences—three common measures of technical merit that are also indicative of the respect that NIST scientists and their work are accorded by their technical peers.

An outstanding technical accomplishment realized by the laboratory in the past year is the demonstration of a frequency standard that utilizes optical radiation rather than microwave radiation. Since optical frequency transitions have much higher precision than that of the microwave frequency transitions that are the basis of current standards and since these optical transitions can now be measured with the required accuracy, a primary frequency standard based on optical transitions with 1,000 times better precision than that of current standards should ultimately be enabled. This development can subsequently translate into similar improvements in measurements of time. Better measurements of time raise the possibility of increasing transmission rates in telecommunications applications, improving the security of military communications, and enhancing the capabilities of the Global Positioning System (GPS) and its applications.

Other examples of noteworthy technical achievements in the laboratory are presented in the divisional reviews below.

Program Relevance and Effectiveness

The panel has noticed an improving focus on the relevance of programs to customer needs in the Physics Laboratory. Areas that have traditionally had strong customer ties—such as standards and calibrations for optical applications and for applications of ionizing radiation—remain strong. A sharp focus on goals and customer needs has been apparent in the new effort to develop chip-scale atomic clocks. The health care initiative, which has been under development for several years, is evolving into a well-organized, cross-laboratory effort. Eight areas of focus in health care have been identified, based on need for standards and measurements and on existing NIST technical strengths. Significant outreach to potential customers in the medical physics community is ongoing.

The laboratory is to be particularly commended for its responsiveness to national need during the anthrax attacks of late 2001. Existing NIST expertise in the measurement of electron-beam dose was quickly mobilized to test the effectiveness of electron-beam decontamination of mail, which allowed the resumption of mail delivery to federal sites. NIST coordinated the interagency task force set up by the White House to address this situation. The dedication and expertise of NIST staff and the existing NIST infrastructure in this area enabled a rapid response to this unanticipated situation and resulted in a reliable decontamination procedure to meet the immediate need to get mail moving again. This technical team continues to work on refining the decontamination procedure to reduce damage to vulnerable mailed objects, such as magnetic recording media. The Physics Laboratory could capitalize on its spectacular success in this effort, and also help accomplish NIST aims in homeland security, by developing an aggressive proposal in this area with appropriate federal and private partnerships.

Suggested Citation:"5 Physics Laboratory." National Research Council. 2002. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories: Fiscal Year 2002. Washington, DC: The National Academies Press. doi: 10.17226/10510.
×

In last year’s assessment,2 the panel noted that clearly articulated strategic goals for the Physics Laboratory would improve program alignment with customer needs and facilitate more effective communication of program relevance both within NIST and to external stakeholders. The panel notes that, in response, the laboratory has developed a revised strategic plan, which is an important first step in strategic program management. The current plan, however, does not appear very useful. It appears to have been written by an outside consultant, with minimal involvement by division managers. The panel found little evidence of the plan’s use for allocating resources relative to priorities and little indication that the divisions understand the laboratorywide goals and priorities enunciated in the plan. In some cases, divisions are receiving mixed signals about the importance of and the level of support for specific programs. The basis for the program prioritization presented in the plan itself remains unclear. The process of creating a strategic plan is probably more important than the final document itself—engaging division management and broad staff representation is necessary if the end result is to be clearly understood goals and priorities and better program focus, relevance, and effectiveness. The panel noted that each division is already carrying out strategic program management to at least some degree; these divisional efforts are the basis on which a useful laboratorywide strategy can be built.

The NIST Physics Laboratory generates significant new knowledge and technology, some of which may have commercial value. It is consistent with the mission of NIST to protect the technology it develops so that it can be used in a manner that best serves the national interests of the United States and its citizens, both individual and corporate. However, there is concern among panel members that NIST staff have only a rudimentary understanding of intellectual property (IP) issues and of methods for transferring NIST IP to U.S. industry. Furthermore, the Physics Laboratory leadership does not encourage the consideration of U.S. IP protection as a deliberate process. Without such deliberate consideration, IP that would contribute more to U.S. competitiveness if protected can fall into the public domain. The panel recommends that NIST management examine its IP policy and focus on clearly communicating that policy to technical staff at all levels so that IP protection is sought when it is appropriate to do so.

Laboratory Resources

Funding sources for the Physics Laboratory are shown in Table 5.1. As of January 2002, staffing for the Physics Laboratory included 196 full-time permanent positions, of which 161 were for technical professionals. There were also 55 nonpermanent or supplemental personnel, such as postdoctoral research associates and temporary or part-time workers.

It is difficult to assess the appropriateness of the current resource allocation within the laboratory because the panel has no indication of how the current allocation of resources was made relative to priorities, potential payoffs, and time horizons. An overall strategy for budget allocation was not presented to the panel, and it is not clear how relative funding decisions are made within the laboratory against overall strategic goals. An overall strategy for resources that accounts for core competencies that must be maintained and that is coordinated with priorities at the NIST level could help ensure continuity of funding for long-term projects and priorities.

The laboratory should evaluate options for the provision of measurement services such as calibrations, Standard Reference Materials, and databases. If mature technologies can be transitioned out of the laboratory (whether through commercialization, the National Voluntary Laboratory Accreditation Program [NVLAP], fee for service, industrial or university partnerships, or other mechanisms), it would

2  

National Research Council, An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories: Fiscal Year 2001, National Academy Press, Washington, D.C., 2001.

Suggested Citation:"5 Physics Laboratory." National Research Council. 2002. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories: Fiscal Year 2002. Washington, DC: The National Academies Press. doi: 10.17226/10510.
×

TABLE 5.1 Sources of Funding for the Physics Laboratory (in millions of dollars), FY 1999 to FY 2002

Source of Funding

Fiscal Year 1999 (actual)

Fiscal Year 2000 (actual)

Fiscal Year 2001 (actual)

Fiscal Year 2002 (estimated)

NIST-STRS, excluding Competence

33.0

33.0

34.0

35.9

Competence

1.6

1.8

3.1

2.3

ATP

1.9

1.9

2.2

2.2

Measurement Services (SRM production)

0.2

0.1

0.1

0.1

OA/NFG/CRADA

10.1

10.6

11.8

13.5

Other Reimbursable

3.6

4.2

4.4

4.5

Total

50.4

51.6

55.6

58.5

Full-time permanent staff (total)a

204

200

205

196

NOTE: Funding for the NIST Measurement and Standards Laboratories comes from a variety of sources. The laboratories receive appropriations from Congress, known as Scientific and Technical Research and Services (STRS) funding. Competence funding also comes from NIST’s congressional appropriations but is allocated by the NIST director’s office in multiyear grants for projects that advance NIST’s capabilities in new and emerging areas of measurement science. Advanced Technology Program (ATP) funding reflects support from NIST’s ATP for work done at the NIST laboratories in collaboration with or in support of ATP projects. Funding to support production of Standard Reference Materials (SRMs) is tied to the use of such products and is classified as “Measurement Services.” NIST laboratories also receive funding through grants or contracts from other [government] agencies (OA), from nonfederal government (NFG) agencies, and from industry in the form of cooperative research and development agreements (CRADAs). All other laboratory funding, including that for Calibration Services, is grouped under “Other Reimbursable.”

aThe number of full-time permanent staff is as of January of that fiscal year.

free NIST scientists involved in those services to spend more time on creative tasks and development of new technologies. The laboratory’s successful establishment of secondary laboratories for medical standards and radiation measurements through the Accredited Dosimetry Calibration Laboratories (ADCLs) is a good example of achieving more optimal use of NIST resources through technology transfer.

Resource limitations call out for maximum leveraging of available resources, not only in cross-divisional work but also in cross-laboratory work within NIST. The panel was pleased to see that the health care initiative being championed by the laboratory is coordinating resources in this area across several NIST laboratories in a meaningful way. As the initiative continues, the panel hopes to see these interlaboratory relationships further nurtured and matured. The Physics Laboratory should continually be alert to other areas in which interlaboratory cooperation can stretch its own resources and provide for results of greatest customer impact.

The panel encourages the Physics Laboratory to take a leadership role in developing consortia and partnerships to address national issues. In addition to fulfilling the mission of NIST, such efforts will raise the public’s and the government’s awareness of the value of NIST. Such activities could leverage industry and public dollars and boost the NIST budget as decision makers perceive the organization to be of high value to the nation.

Several division managers were concerned that rising NIST overhead rates are consuming greater

Suggested Citation:"5 Physics Laboratory." National Research Council. 2002. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories: Fiscal Year 2002. Washington, DC: The National Academies Press. doi: 10.17226/10510.
×

percentages of their budgets. Data indicates that the overhead rate has risen from 44 percent in 1997 to 54 percent in 2002. Without a detailed review of what the overhead rate supports and what base it is charged against, the panel cannot determine if this rate is inappropriate. However, the panel is concerned about the impact it has on the resources available for technical programs. The overhead rate might merit review by the NIST director.

Laboratory Responsiveness

The primary recommendation made by the panel in its previous report was to improve the focus of programs through clearly articulated, overall strategic goals for the Physics Laboratory. As noted above, the laboratory took the first step toward responding to this recommendation. Much work remains to be done in order to produce the coherent, well-understood strategy for the laboratory that is necessary to achieve the program focus and coordination that the panel envisions. As this is clearly not a 1-year process and must emanate from the divisions, the panel looks forward to continued progress on this topic.

Last year, when presented with a Physics Laboratory initiative in biophysics, the panel remarked that the initiative, as presented, lacked focus and did not have an obvious role for Physics Laboratory competencies. Since that time, the initiative has been refocused into the area of health care, and has been developed into a NIST-wide Strategic Focus Area (SFA). While much of the planning and prioritizing that went into this new health care SFA occurred at a level higher than the Physics Laboratory, the laboratory is to be commended for the active role it played in its development and for the leadership that it is showing in the organization and management of the interlaboratory effort.

In last year’s assessment, the panel also recommended clearer program goals for the laboratory in the area of nanotechnology. Nanotechnology has now been raised to the level of a NIST-wide initiative, and the Physics Laboratory program has benefited from the increased focus and strategy that planning on the NIST level is bringing to work in this area. Furthermore, the Physics Laboratory has engaged in numerous nationally sponsored nanotechnology activities to firmly establish the leadership role of NIST in this important emerging area. At this time, a clear definition of specific Physics Laboratory goals in nanotechnology would help assure the best application of resources in this area.

The panel was particularly impressed with the responsiveness of the Atomic Physics Division to last year’s report and recommendations. In response to panel concerns about the relevance of work in Gaseous Electronics Conference (GEC) reference cells, the division examined its program in that area, determined an appropriate focus for research, and redirected its efforts accordingly. The panel was impressed with how quickly and effectively the division was able to make changes in order to allocate its resources in this area more effectively.

MAJOR OBSERVATIONS

The panel presents the following major observations:

  • The Physics Laboratory continues its tradition of technical excellence and leadership. The awarding of the 2001 Nobel Prize in Physics to one of the laboratory’s staff members is the most obvious evidence of this excellence.

  • The Physics Laboratory reaction to the anthrax attacks of late 2001 was outstanding for its responsiveness to unanticipated national need and for its excellent utilization of established NIST skills and resources. Staff involved in this effort are deserving of the highest praise and gratitude.

Suggested Citation:"5 Physics Laboratory." National Research Council. 2002. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories: Fiscal Year 2002. Washington, DC: The National Academies Press. doi: 10.17226/10510.
×
  • The panel commends the leadership role that the Physics Laboratory is taking in the NIST-wide health care initiative and the strong focus that the laboratory has brought to its efforts in this area in the past year.

  • The Physics Laboratory must continue to develop a strategic planning and prioritization process that results in clear laboratory goals and priorities which can be used by the laboratory and its divisions to allocate resources, determine program prioritization, and produce enhanced program focus and effectiveness.

  • The panel recommends enhanced efforts to develop interlaboratory collaborations and other partnerships that would help leverage Physics Laboratory resources while more effectively meeting NIST-wide strategic goals.

DIVISIONAL REVIEWS

Electron and Optical Physics Division

Technical Merit

The Electron and Optical Physics Division’s mission is to support the NIST mission by developing the measurement capabilities needed by emerging electronic and optical technologies, particularly those required for submicrometer fabrication and analysis. The division is composed of three groups: Photon Physics, Electron Physics, and Far UV Physics.

Photon Physics. The principal focus of the Photon Physics Group is the creation and characterization of metrology tools and methods in the spectral region of extreme ultraviolet (EUV) radiation. This spectral region is of considerable importance and relevance owing to the development of EUV lithography, which is the strongest candidate to follow deep ultraviolet (DUV) lithography, currently used in volume production of integrated circuits (IC). The availability of production-ready EUV lithographic tools at the end of this decade will be critical for maintaining U.S. competitiveness in the field of advanced IC fabrication.

The group’s Synchrotron Ultraviolet Radiation Facility (SURF III) is an EUV radiation source that can be selected for the wavelength regions relevant to lithography, principally centered at 13.5 nm and 157 nm. Extensive work has been done over the past year on the RF drive electronics used to maintain electron energy inside the SURF’s storage ring. SURF III has several radiation ports dedicated for use in the characterization of EUV detectors and mirrors. The reliable EUV output provided by SURF III and the dedication of several radiation ports for EUV work provides a significant measurement capability.

Last year the Photon Physics Group completed the large-sample EUV reflectometry facility. This is one of the few facilities in the world able to characterize the large (up to 40-cm diameter) EUV mirrors needed by industry for full-field lithographic exposure tools. The Photon Physics Group is one of five participants worldwide in a round-robin measurement testing exercise in the characterization of EUV mirrors. Five different mirrors, each produced by a separate laboratory, have been measured by each facility; comparison results were presented in March 2002 at the Society for Photo-Optical Instrumentation Engineers (SPIE) microlithography conference.

At the present time, a very limited commercial EUV detector infrastructure exists, and no commercial calibration services are available for EUV detectors. The Photon Physics Group’s ability to characterize and calibrate EUV detectors is an important factor in the growth of this technology. In addition, this group is uniquely positioned to investigate a fundamental assumption made by nearly all users of

Suggested Citation:"5 Physics Laboratory." National Research Council. 2002. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories: Fiscal Year 2002. Washington, DC: The National Academies Press. doi: 10.17226/10510.
×

calibrated EUV photodiodes. These EUV photodiodes are calibrated with quasi-continuous wave (CW) synchrotron radiation sources but are then used to measure the output from pulsed EUV light sources. The calibration is assumed to be consistent between CW and pulsed operation of these photodiodes. The Photon Physics Group has constructed a pulsed EUV radiation source based on the gas jet laser-produced plasma concept, and it plans to compare calibration with this pulsed source to that made with the quasi-CW output from SURF III.

Many research organizations around the world are developing EUV light sources, each following quite a different technological path. Consistent measurement of source parameters such as average in-band emission, in-band emission stability, out-of-band emission, source size, source position stability, and debris generation is critical when making comparisons among EUV source suppliers. The expertise of the Photon Physics Group and the reputation of NIST make it ideally suited for creating this suite of tests. It is recommended that the Photon Physics Group approach EUV source vendors and EUV exposure tool suppliers and ascertain the level of interest in providing this function to the EUV technical community.

Because of the clean, debris-free output and extended continuous operation capability of SURF III, the Photon Physics Group is well positioned to contribute to important studies of EUV mirror lifetime and degradation mechanisms. To date, industry emphasis has been placed on developing strategies directed toward mitigation of mirror damage caused by contaminants such as carbon and oxygen. Little is known about possible degradation of the dielectric coatings under long-term exposure to EUV radiation. The clean, high-vacuum environment afforded by a synchrotron radiation source such as SURF III is essential for achieving long-term EUV exposures free from contaminants. The division should consider pursuing funding for such work.

Electron Physics. The Electron Physics Group pioneers the development of world-class measurement techniques and uses them to confront challenging problems at the nanoscience frontier. Last year the panel reported on the completion of the Nanoscale Physics Laboratory (NPL), a scanning tunneling microscope (STM) coupled to two molecular beam epitaxy (MBE) systems and a field ion microscope unit for tip preparation. A fixed-direction magnetic field as large as 10 T or a variable-orientation field up to 1.5 T can be applied to a sample. The system can operate at temperatures as low as 2 K. This facility positions the group to remain a leader in the preparation and characterization of nanostructured materials well into the future. Recent improvements in the system’s electronics have made it possible to resolve meV features. A fascinating study currently under way on this system employs the spin-dependent STM capability to enable spectroscopic investigation of energy gap states in superconducting V3Si films grown in situ. NIST has observed magnetic tunneling effects on the subnanometer scale that do not fit conventional models. This discovery of new physics is a good indication that the experiments probe uncharted territory. Testing of atom manipulation has also begun, as part of the larger goal of developing an autonomous atom assembler that will afford atom-by-atom fabrication of quantum structures.

Single-atom manipulation is also the objective of the “atom on demand” work, which relies on capturing an individual atom in a magneto-optical trap and moving it with lasers. Potential applications include building an atomic array for quantum information processing and modulated doping of a substrate. The essential step of counting the number of atoms in the trap was accomplished in 2001 by detecting their fluorescence. This project dovetails very well with the quantum computing effort at Boulder and gives NIST an edge in this very competitive field.

The Scanning Electron Microscopy with Polarization Analysis (SEMPA) project was enhanced with the installation of an ultrahigh vacuum, field emission scanning electron microscope during 2000-2001. This instrument is now functioning at a magnetic image resolution of 25 nm, with an ultimate goal of achieving 10-nm resolution. A critical need exists for mapping the magnetic domain structure

Suggested Citation:"5 Physics Laboratory." National Research Council. 2002. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories: Fiscal Year 2002. Washington, DC: The National Academies Press. doi: 10.17226/10510.
×

on that scale because it is characteristic of magnetic storage media for hard disks. Owing to vendor delays in meeting specifications, the instrument has not quite reached 10-nm resolution, but it is already better than the available magnetic microscopes, such as other SEMPA instruments, the MFM (magnetic force microscope), and the PEEM (photoemission electron microscope) with magnetic circular dichroism. Measurements can be made in the 100 to 1000 K temperature range, and structures such as multilayer wedges can be grown by MBE and characterized with techniques including reflection high-energy electron diffraction. Two recent SEMPA efforts are very exciting. First, magnetization directions of magnetic nanostructures in patterned thin films were imaged directly. The structures are Fe and Co disks and rings several nanometers thick and 1 to 10 mm in diameter that have potential application in nonvolatile magnetic memories. Second, electron-beam-induced magnetic switching has been observed in epitaxial Fe (110) films grown on a GaAs (110) surface.

A high-risk effort is under way to achieve atomic-scale magnetic contrast in a separate, room-temperature STM. One set of experiments is designed to monitor the circular polarization of light generated by tunneling from a ferromagnetic sample into a p-doped GaAs tip. If this technique is viable, several impediments to obtaining magnetic contrast using magnetic tips will be eliminated, including undesirable tip-sample interactions, unknown orientation of the tip magnetization, and lack of distinction between magnetization and topographic images. Novel work on magnetic tips is being pursued in parallel. This group’s pioneering work on spin-polarized electron emission from GaAs photocathodes (the reverse of the process investigated by STM) is the most frequently cited paper in Review of Scientific Instruments over the last 30 years.

A talented and creative theoretical component complements the experimental effort. Interacting with researchers within as well as outside NIST, the theorists generate ideas for experiments and provide an additional resource for problem solving. One theorist works in a highly collaborative manner; for example, NIST experimentalists, a NIST theorist, and scientists from the Naval Research Laboratory (NRL), IBM, and Oxford and Cambridge Universities collaborated on spin polarization in STM. Among recent theoretical activities are an investigation of noncollinear spin transfer in Co/Cu/Co multilayers and work on the impact of spin-other-orbit interactions on the magnetocrystalline anisotropy energy of the 3d transition metals.

Far UV Physics. The Far UV Physics Group operates and continually improves SURF III. A newly installed near-UV Fourier transform interferometer will provide high-precision optical constants for the next-generation (157-nm) optical lithography. An upgrade of the RF system is under way to allow better control of the third harmonic of the resulting radiation beam, which will make it possible to control instabilities at low beam energies, resulting in more precise measurements for SURF III users.

As pointed out in the previous assessment report, opportunities exist for exploiting the unique capabilities of SURF III in producing spectrally pure and easily tunable photons in the 3- to 6-eV energy regime, which covers the range of work functions. One option would be to install a photoelectron microscope that uses work function differences for producing contrast. Near threshold, the chromatic aberrations are negligible that affect the resolution at the higher energies used by other synchrotron light sources. Infrared spectroscopy and microscopy will benefit from the improved beam stability. The group should consider the possibility of exploiting these capabilities.

Program Relevance and Effectiveness

Many organizations are in crucial need of the capabilities and knowledge base of the Electron and Optical Physics Division. Among the customers of the Photon Physics and Far UV Physics Groups are

Suggested Citation:"5 Physics Laboratory." National Research Council. 2002. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories: Fiscal Year 2002. Washington, DC: The National Academies Press. doi: 10.17226/10510.
×

companies and agencies that need calibration standards for radiometry such as calibrated photodiodes, calibrated charge-coupled detectors for solar activity (Naval Research Laboratory), and transmission gratings for space astronomy. One large customer is the EUV Limited Liability Corporation (LLC) consortium, whose members include Intel, Motorola, Advanced Micro Devices (AMD), Lawrence Livermore National Laboratory (LLNL), and Lawrence Berkeley National Laboratory (LBNL). Major objectives of the consortium are quantitative assessment of radiation damage and lifetime of EUV optics, determination of optical constants, and reflectivity measurements for mirrors.

The pioneering research activities of the Electron Physics Group in nanoscale science and technology ensure the work’s relevance to a wide spectrum of customers across industry, academia, and government. For example, the SEMPA capability for high-resolution magnetic imaging has spawned current collaborations with Seagate; IBM; MIT; Cambridge University; the Johns Hopkins University; the University of California, San Diego; the University of Utah; and NRL. Given its promise for fabricating nanostructures atom by atom and for measuring their electronic and magnetic properties, the Nanoscale Physics Laboratory is likely to generate customer interest on a number of fronts—among them, atom manipulation for device structures, the study of the intrinsic physics of atom-solid interactions, and quantum computing. As indicated above, quantum information processing and modulated doping are also potential application arenas for the “atom on demand” effort.

Results of division research are shared with customers by many different means, including direct communications, presentations at technical meetings, and reports. The substantial number of high-quality papers by division researchers in the refereed scientific literature is especially noteworthy. The panel expects that the division will maintain this level of presence in the external technical community.

Division Resources

Funding sources for the Electron and Optical Physics Division are shown in Table 5.2. As of January 2002, staffing for the division included 23 full-time permanent positions, of which 20 were for

TABLE 5.2 Sources of Funding for the Electron and Optical Physics Division (in millions of dollars), FY 1999 to FY 2002

Source of Funding

Fiscal Year 1999 (actual)

Fiscal Year 2000 (actual)

Fiscal Year 2001 (actual)

Fiscal Year 2002 (estimated)

NIST-STRS, excluding Competence

5.0

5.4

5.5

5.5

Competence

0.0

0.0

0.2

0.2

ATP

0.2

0.1

0.2

0.1

OA/NFG/CRADA

0.6

0.5

0.8

1.2

Other Reimbursable

0.1

0.1

0.0

0.0

Total

5.9

6.1

6.7

7.0

Full-time permanent staff (total)a

23

23

24

23

NOTE: Sources of funding are as described in the note accompanying Table 5.1.

aThe number of full-time permanent staff is as of January of that fiscal year.

Suggested Citation:"5 Physics Laboratory." National Research Council. 2002. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories: Fiscal Year 2002. Washington, DC: The National Academies Press. doi: 10.17226/10510.
×

technical professionals. There were also 9 nonpermanent or supplemental personnel, such as postdoctoral research associates and temporary or part-time workers.

Funding for the division is adequate, although maintaining it requires persistent struggle. It appears that projects that successfully attract funding are frequently “taxed” to fund new initiatives. Division staff also reported a large increase in overhead charges during the past 2 years.

Morale is excellent. In general, the members of the division greatly enjoy the intellectual stimulation and excitement of working on very interesting projects with talented colleagues. The fact that NIST scientists have received two Nobel prizes over the past 5 years is in no small part responsible for the high level of enthusiasm.

Atomic Physics Division

Technical Merit

The mission of the Atomic Physics Division is to carry out a broad range of experimental and theoretical research in support of emerging technologies, industrial needs, and national science programs. It is organized in five groups: Plasma Radiation, Quantum Processes, Laser Cooling and Trapping, Atomic Spectroscopy, and Quantum Metrology.

Plasma Radiation. The Plasma Radiation Group operates the laboratory’s electron-beam ion trap (EBIT), a unique, well-characterized facility that allows fundamental studies of a variety of processes with highly charged ions for both fundamental science and applications. Through the use of EBIT, the division continues to be a leader in studies of fundamental properties of highly charged ions. This well-instrumented, well-characterized facility allows the division to make unique and important contributions on a wide variety of topics. Most recently, a new cutting-edge space-compatible microcalorimeter allowed the group to make a number of studies of astrophysical significance.

Over the past several years, this group has been exploring the application of highly charged ions for surface modification and processing. After an initial exploratory procedure, the group has focused its efforts on using ions for the production of nanostructures on the surfaces of silicon and silicon dioxide, with potential applications in microelectronics and biotechnology. The division developed expertise in the imaging of this surface, and it seems that this activity could be poised to produce some significant results in the next 12 to 18 months.

The Plasma Radiation Group is successfully pursuing optical measurements of the properties of optical materials at the 157-nm wavelength so important to future-generation lithography for integrated circuits. The group discovered intrinsic birefringence 10 times the design limits for the key materials CaF2 and BaF2 and is currently working on solving this intrinsic birefringence problem.

Quantum Processes. The Quantum Processes Group is one of the few theoretical atomic, molecular, and optical (AMO) physics groups in the United States; as such, it is a national resource and plays an important leadership role in the theoretical AMO community in the United States. The group provides important theoretical support for a variety of experimental efforts in atomic clocks, quantum degenerate gases, quantum dots, single-molecule detection, and quantum information. The group is distinguished by its emphasis on realistic models of the processes under study, and for this reason it is often able to confront experiments in meaningful ways. Over the years, this group has developed a number of numerical codes and applied them successfully to a wide variety of physical, chemical, and optical phenomena. It is also playing an important leadership role in the NIST Quantum Information initiative.

Suggested Citation:"5 Physics Laboratory." National Research Council. 2002. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories: Fiscal Year 2002. Washington, DC: The National Academies Press. doi: 10.17226/10510.
×

Over the past year, the Quantum Processes Group has made a number of significant advances. It has developed and is continuing to develop methods for theoretically analyzing the collisional properties of atoms confined in optical lattices, in particular, simulating the process of generating entanglement. It has advanced a strikingly successful theory of the complex collisional behaviors of ultracold Cs atoms. It has advanced the art of simulation of quantum dots. Its simulations of nanoscale optics have led to key new insights into the interpretation of near-field scanning microscopy images. The group continues to interact strongly and fruitfully with the Laser Cooling and Trapping Group and with other NIST scientists outside the Atomic Physics Division.

Laser Cooling and Trapping. Extremely active, productive, and visible, the Laser Cooling and Trapping Group is one of the world’s leading groups in the field of cold atoms and Bose-Einstein condensation. The level of interaction between senior scientists is extremely healthy and is attracting many first-rate postdoctoral fellows.

The unusually fruitful collaboration between the experimentalists in this group and the theorists in the Quantum Processes Group is noteworthy. The theorists have immediate access to new experimental data, and that leads to meaningful theory rather than to a toy model approach with minimal relevance to the real world. The interaction creates a synergy in which the experimenters and theorists share the lead to new developments.

Atomic Spectroscopy. The Atomic Spectroscopy Group plays a prominent and visible role in providing essential support for the national scientific and industrial infrastructure, in the form of critical evaluations of the fundamental constants and atomic data. The group is aggressively pursuing a dramatic shortening of the time between comprehensive fundamental constants updates—from 13 years to 4 years. The accelerated process is enabled by a new, Tex-based data entry system, allowing real-time entry and proofreading. The Atomic Data Center provides critically evaluated data on atomic spectroscopy, a service of tremendous value, as evidenced by the roughly 1 million hits per year on its Web site by commercial, academic, governmental, and international users.

Quantum Metrology. The Quantum Metrology Group works primarily in the use of x-rays and gamma-rays for wavelength standards, materials optical properties, and determination of binding energies through the use of gamma-ray spectroscopy, and other precision measurements. Closely coupled to these areas is a program on atomic displacement metrology for achieving a better understanding of errors in interferometric measurements so that these techniques may be extended in their range and accuracy (which is related to the x-ray work of the group through x-ray interferometry). These activities are world-class in caliber and clearly support a core function of NIST. In addition, work is ongoing to investigate issues in high-resolution x-ray diffraction and reflectometry, particularly as applied to semiconductor-related problems and biological materials. Although these programs are relatively new and have not gained the international status of the group’s other programs, they are technically sound and also relate to a core function of NIST. This group also provides its expertise in x-ray optical systems to the U.S. inertial fusion program by designing a diagnostic module for the NRL to be delivered to the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory.

Program Relevance and Effectiveness

The panel commends the Atomic Physics Division for clearly and coherently responding to issues raised by previous panel reports.

Suggested Citation:"5 Physics Laboratory." National Research Council. 2002. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories: Fiscal Year 2002. Washington, DC: The National Academies Press. doi: 10.17226/10510.
×

The EBIT team has established a productive relationship with astrophysicists at Harvard University supporting present and future orbiting x-ray instruments—Chandra, X-ray Multi-Mirror (XMM), and Constellation X. The Harvard group is currently developing a dedicated instrument to mount on the EBIT.

It is imperative that the EBIT surface team continue to interact closely with academic and industrial collaborators to ensure both that their new techniques are unique and that they address current microelectronics and biotechnology needs.

In response to panel concerns, GEC reference cell work is now focusing on submillimeter absorption spectroscopy diagnostics for plasma processing. Two companies, Air Products and Lam Research, are actively interested in collaborations with NIST for the use of this work for diagnostics of commercial etching reactors. Although the NIST GEC cell is not unique, the applications of the cell at NIST appear to be unique and of demonstrable utility in an important commercial sector.

Work on the optical properties of CaF2 and BaF2 at 157-nm and shorter wavelengths provides important information to designers of optical systems for 157-nm lithography and has already had an impact on the designs of some lens systems for next-generation lithography. This work is well aligned with one of the laboratory’s Strategic Focus Areas—optics—and these measurements appear to be unique in the world. The concept of developing Ca1xBaxF2 compounds to mitigate the effects of birefringence is clearly worth pursuing. The group needs to remain “ahead of the game” in order to be prepared for future generations of UV lithography systems.

As one of the very few AMO theory groups in the country, the Quantum Processes Group plays a vital role in supporting experimental efforts across the nation. The group’s efforts in supporting fundamental and applied AMO science overlap strongly with the NIST core measurement and metrology functions. For example, its theoretical work in quantum information will directly support advances in quantum measurements of great importance to standards.

The Atomic Spectroscopy Group’s evaluations of fundamental constants are also central and vital to the NIST core mission.

Work on critical evaluation and compilation of atomic data remains vibrant. The online data archive has addressed every problem raised in user feedback, and important new spectra have been added relevant to fusion research, microlithography, commercial lighting, and astrophysics. The Web-based data archive (physics.nist.gov/cgi-bin/AtData/main_asd) continues to enjoy more than 70,000 hits per month. Of particular note is a new Web-based archive of spectral data needed for the interpretation of x-ray observations obtained by the orbiting Chandra observatory. A potentially very useful new product, a handbook of the most commonly used spectroscopic data for neutral and singly ionized atoms of 99 elements, will be available in printed form and electronically later in 2002.

The division has a new CRADA in support of the lighting industry, involving a consortium of Phillips, General Electric, the University of Wisconsin, the University of Illinois, Los Alamos National Laboratory (LANL), NIST, and the Electric Power Research Institute (EPRI). One important objective of this work is improvement of the efficiency of plasma light sources used throughout the United States. Currently there are about 1 billion such sources, consuming roughly 100 GW of electric power annually. Even a 10 percent improvement in power consumption efficiency would translate into energy savings equivalent to production from multiple large power plants.

A connection between NIST and industry is being developed under the Consortium for High-resolution X-ray Calibration Strategies. This effort is to be commended, and similar collaborations should be sought in the area of x-ray activities related to biological systems to ensure that the division’s proposed work is relevant. Similar consortiums or collaborations might also be considered between NIST and the third-generation x-ray synchrotron sources, which pursue topics similar to those being

Suggested Citation:"5 Physics Laboratory." National Research Council. 2002. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories: Fiscal Year 2002. Washington, DC: The National Academies Press. doi: 10.17226/10510.
×

TABLE 5.3 Sources of Funding for the Atomic Physics Division (in millions of dollars), FY 1999 to FY 2002

Source of Funding

Fiscal Year 1999 (actual)

Fiscal Year 2000 (actual)

Fiscal Year 2001 (actual)

Fiscal Year 2002 (estimated)

NIST-STRS, excluding Competence

6.7

6.8

7.3

7.0

Competence

0.3

0.3

0.7

0.5

ATP

0.2

0.3

0.3

0.4

OA/NFG/CRADA

0.8

1.1

1.7

1.5

Other Reimbursable

0.2

0.1

0.0

0.1

Total

8.2

8.6

10.0

9.5

Full-time permanent staff (total)a

32

31

35

34

NOTE: Sources of funding are as described in the note accompanying Table 5.1.

aThe number of full-time permanent staff is as of January of that fiscal year.

addressed at NIST (high-precision angle measurement; comparison of surface roughness measurements using visible light, x-rays, and atomic force microscopy; and so on).

Division Resources

Funding sources for the Atomic Physics Division are shown in Table 5.3. As of January 2002, staffing for the division included 34 full-time permanent positions, of which 26 were for technical professionals. There were also 11 nonpermanent or supplemental personnel, such as postdoctoral research associates and temporary or part-time workers.

The division is concerned about steadily increasing overhead rates. The panel perceives significant increases in NIST-wide administrative loads—both financially (overhead) and in terms of the amounts of time required of division personnel. Funding for this division has been effectively decreasing for several years, and the panel is concerned for its long-term financial health.

In order to meet its computing needs, the division is currently maintaining its own computer networks using permanent scientific staff, while paying for NIST-wide services via overhead. This is a burden on key staff talent. The division should investigate other means to meet its networking needs.

Given the attrition of an aging staff, the long-term future of the Atomic Spectroscopy Group has been one of the major concerns of the panel over the past 3 years. Laboratory management was strongly committed to shoring up this area by devoting significant funding to underwrite a 7-year plan to acquire first-rate young talent and to foster the mentoring of the new people by senior staff. This 7-year initiative has now been prematurely terminated. The loss of this funding has been offset by new funding freed up as a result of a retirement, so there is no immediate problem with funding. However, this is likely a short-term fix. The hiring of new staff members in this area has gone slowly and has suffered several setbacks—ever-increasing overhead rates and salaries that must be absorbed within a fixed pool of salary money, and loss of funding support from NASA. The NIST atomic database is unique in the world. Most other such databases rely on the NIST database as their primary source for critically

Suggested Citation:"5 Physics Laboratory." National Research Council. 2002. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories: Fiscal Year 2002. Washington, DC: The National Academies Press. doi: 10.17226/10510.
×

evaluated atomic data. There will be a major ripple effect if the NIST database work is abandoned in the future. The panel would strongly disagree with any NIST decision to abandon its long-standing commitment to provide this critical resource to the national and international scientific, defense, and commercial sectors.

Currently, the Quantum Metrology Group consists of only four permanent staff members. This past year the group’s long-time leader passed away, leaving a void in the group’s vision and prioritizing. It is difficult to see how the group can continue all of its programs and complete them in a timely manner, given the limited number of personnel available. Under flat budgets, difficult decisions will have to be made to postpone or curtail some programs; otherwise, all programs will suffer. Without additional resources and manpower, insufficient funding will be available to adequately support the group’s current, wide-ranging activities.

Optical Technology Division

Technical Merit

The Optical Technology Division’s stated mission within NIST is to advance knowledge; to develop expertise; to provide technical leadership; and to deliver the highest-quality standards, calibrations, and measurements in targeted areas of optical technology. Optics and optical technology are broadly construed to include the spectral range from the microwave region to the vacuum ultraviolet (VUV). The division’s goals in their totality are unique within the U.S. science and technology infrastructure, as are the division’s current capabilities to meet them. The division is organized in four groups: Optical Thermometry and Spectral Methods, Optical Properties and Infrared Technology, Optical Sensor, and Laser Applications. For this division, organization by groups is largely administrative, as productive interaction among individuals, groups, and other NIST laboratories is an avowed goal of division management. Consequently, the assessment presented below is not organized explicitly by group but aims to provide an integrated discussion of the activities of the division.

The activities of the Optical Technology Division are diverse, encompassing areas from basic research on light-matter interactions, to applications of light scattering as a metrological tool for the characterization of solid surfaces, to sustained interactions with scientists and engineers in establishing methodologies and standards for industries relying on optical technologies. The division has targeted research programs to develop optical and spectroscopic tools for gathering information on processes in the frequency ranges required to support evolving technologies in the semiconductor, biotechnology, health science, and other industries. The research also aims to solve fundamental problems in the physics, chemistry, and engineering science that underlie these applications. The Optical Technology Division also has the institutional responsibility for maintaining two base SI units: the unit of temperature above 1234.96 K and the unit of luminous intensity, the candela. The division also maintains the national scales for other optical radiation measurements and ensures their relationship to the SI units. These measurement responsibilities include derived photometric and radiometric units, the radiance temperature scale, spectral source and detector scales, and optical properties of materials, such as reflectance and transmittance.

The Optical Technology Division is involved in the development and application of new methods to make the far-infrared and submillimeter-wave spectral regions more accessible. This effort is part of a broader, laboratorywide competence initiative in terahertz measurements. The program aims to extend and improve capabilities for optical measurements in the far-infrared, traditionally one of the most inaccessible portions of the electromagnetic spectrum, but one of great spectroscopic importance for

Suggested Citation:"5 Physics Laboratory." National Research Council. 2002. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories: Fiscal Year 2002. Washington, DC: The National Academies Press. doi: 10.17226/10510.
×

many disciplines and technologies. Several distinct approaches are being pursued within the division. One of these relies on CW terahertz techniques, including photomixing with tunable visible lasers. Another relies on unique, high-performance electron devices. A complementary set of techniques exploits the capabilities of ultrafast pulsed lasers. In this scheme, ultrafast electromagnetic transients are produced from laser pulses by photoconductivity or optical rectification. The electromagnetic transients are characterized directly in the time domain by sampling techniques using a copy of the ultrafast laser pulse that produced them. These diverse investigations in their totality clearly place NIST at the forefront of an extremely vital and rapidly evolving active technical area. They build on the division’s traditional strength in infrared spectroscopy, including novel, multichannel detection schemes. In addition to establishing these new spectroscopic capabilities, the effort has led to unique measurements of physical and chemical systems with high scientific impact and implications for plasma processing, biotechnology, and other areas of national priority.

Another current frontier in optical spectroscopy concerns the analysis of small structures. This capability may apply to probing thin films, surface layers, organic and inorganic nanostructures, and single molecules—all structures of great scientific and technological importance. The division is carrying out research to develop or adapt spectroscopic techniques to examine material of reduced spatial dimensions and to perform unique scientific measurements using these capabilities. These activities are well aligned with other major initiatives in NIST and with areas of external importance, such as biotechnology, nanotechnology, photonics, and electronics. One component of the research program emphasizes precision measurements of surfaces and interfaces. The broadband, infrared-visible sum-frequency generation spectroscopy pioneered in the division combines the power of an interface-specific optical technique with the capability for rapid data collection of vibrational spectra. The division team has demonstrated the power of this approach in polymer interfaces and other material systems. This new research builds on the division’s established expertise in the precise analysis of optical scattering and from its unique instrumentation. The program has elucidated fundamental issues and has been tightly coupled to materials characterization in the semiconductor industry. Results are being disseminated to customers through publicly available software for scattering analysis that can be downloaded from the NIST Web site.

A current initiative for spectroscopy of small structures concerns the extreme limit of single-molecule detection. Leading-edge work in developing the necessary tools and techniques for such measurements and their applications to biological problems are being vigorously pursued. This project builds on the expertise developed in the Optical Technology Division in the application of confocal and near-field microscopy to biological and biomimetic systems. The division has recently placed emphasis on the extension of fluorescence resonant energy transfer techniques to the single-molecule level for determination of distances on the nanometer scale. These investigations, supported by NIST competence funding for single-molecule measurement and manipulation, have the potential for significant impact in biophysics and biotechnology.

Radiometry, photometry, and spectrophotometry remain central to the division. This area has very close coupling to industry, and new innovations and requirements in diverse sectors drive new scientific and standards development. For example, new applications of light-emitting diodes (LEDs) for illumination and displays have stimulated considerable innovation in metrology and standards for photometry and colorimetry. The division has done an impressive job of evolving and adapting its tools and standards to address these technology changes. A truly innovative effort to improve the accuracy of laser photometry and the calibration of transfer standards is the High Accuracy Cryogenic Radiometer (HACR 2) Program. When complete, this instrument should provide a combined relative uncertainty of <0.01 percent, the best in the world.

Suggested Citation:"5 Physics Laboratory." National Research Council. 2002. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories: Fiscal Year 2002. Washington, DC: The National Academies Press. doi: 10.17226/10510.
×

The division’s Facility for Automatic Spectroradiometric Calibrations (FASCAL) provides the basis for spectral irradiance and radiance measurements for U.S. industry, the scientific community, and the military. This facility is currently being upgraded to a second-generation instrument, FASCAL 2, which will improve the quality of calibration and the throughput. Both improvements are of significant benefit to users and are a direct response to long-expressed customer needs. FASCAL 2 will define best-in-the-world for the calibration of spectral irradiance sources. The FASCAL 2 system was designed to enable the transfer of the NIST spectral irradiance detector scale to sources used by NIST customers. In the past year, this chain of realization was actually implemented with the current FASCAL. Very significant reductions in uncertainty are now realized on all calibrations, but particularly in the near-infrared. The planned comparison of radiance and irradiance scales to establish the basic equivalence of their methods of realization and to estimate the importance of any experimental bias will further establish the certainty of the NIST realizations. The panel commends the division for having committed personnel, space, instrumentation funds, and other resources to the FASCAL upgrade project.

Optical technology plays a key role in the semiconductor industry, and NIST provides support through standards and optical characterization of materials. Over the past years, very rapid progress in photolithography has been achieved by moving quickly to shorter wavelengths—from mercury lamp-based illumination to 248-nm and more recently 193-nm pulsed excimer laser illumination sources. Many of the laboratory’s programs are relevant to current photolithography, particularly those related to calibration, damage resistance, and stability of detectors at 193 nm and 157 nm. This relevance is becoming more important as illumination sources increase in average power, peak power, and repetition rate where detector nonlinearities, durability, and reliability become more questionable. The division’s SURF III is unique and will enable critical metrology for the industrialization of DUV and VUV photolithography. This work should be accelerated, however, to match the time lines of the semiconductor industry.

Program Relevance and Effectiveness

The Optical Technology Division has a broad and significant mandate to address with limited resources. To this end, the division aims to focus on high-potential and high-impact activities at a level sufficient to maintain and enhance the global position of the United States in the relevant areas of science and technology. The panel’s overall assessment is that the division is doing an outstanding job in choosing technical directions, in developing outside interactions, and in maintaining and upgrading facilities to ensure the highest degree of program relevance and effectiveness.

In carrying out the programs of the Optical Technology Division, there is constant need to evaluate and reevaluate priorities. The division mission encompasses needs that are changing rapidly, driven by the evolution of new technologies and by the need for improved metrology for existing technologies. This requires a dynamic program and also provides the impetus for the division’s efforts in basic, long-term theoretical and experimental research. In this sense, the division’s mission follows the two themes of the Physics Laboratory’s mission: physics applied to support emerging technologies and physics applied to developing advanced measurement standards. The panel believes that a very suitable planning and management structure is in place to ensure program relevance and effectiveness. The division benefits from the inclusive, dynamic strategic planning approach implemented some years ago, as well as from broader discussions on the level of the Physics Laboratory and strategic planning for NIST. The division’s effectiveness and relevance are enhanced by strong interactions with other divisions within NIST and with other government, industrial, and academic laboratories.

A central aspect of the division’s priority setting involves interactions with the Council for Optical

Suggested Citation:"5 Physics Laboratory." National Research Council. 2002. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories: Fiscal Year 2002. Washington, DC: The National Academies Press. doi: 10.17226/10510.
×

Radiation Measurements (CORM), which evaluates national needs in optical metrology and provides feedback on the services and standards supplied by the division. The division could further enhance the effectiveness of CORM by ensuring the broadest representation on and participation in CORM by the biomedical community. Also, as a procedural matter, CORM members are currently polled on their priorities before the issuance of the NIST response to the previous CORM report; the new CORM report essentially coincides with the NIST response to the old report. A mutual agreement should be sought between NIST and CORM whereby NIST produces its response at a fixed time (2 to 3 years) after the issuance of the CORM report. Up to 1 year should be allowed for assessment of the response. The polling for the next CORM report might then be initiated. The division has also maintained a dialogue with the UV Measurements Focus Group of the industrial association RadTech International North America. The division participates in the focus group’s meetings and advises on its activities. The leadership of this focus group is now also involved in CORM.

The effectiveness and relevance of the division’s projects may be gauged by the strong interactions of the division with industrial, government, and academic colleagues and customers and the level of support for ongoing projects from other government agencies, industry, and the ATP program. By this measure, the division’s programs are very highly valued. The division’s effectiveness and relevance are also reflected in its record of publications and presentations. Given the relatively small size of the effort, both the numbers and their scientific impact are excellent, a result attributable to both the quality of the researchers and their aggressive pursuit of new scientific directions. Adopting new directions has often required phasing out well-established directions that have significant but diminished scientific and technological relevance. Such steps are generally difficult and painful; the panel commends the division for taking such decisions.

The panel cites below a few examples of recent activities whose relevance and effectiveness are particularly high.

Especially noteworthy are the division’s characterization and theoretical understanding of the phenomenon of intrinsic birefringence in transparent materials of cubic symmetry in the VUV spectral region. The existence of a measurable effect of this sort, seen in CaF2 and other fluoride crystals, came as a surprise to optical scientists and engineers. Given the crucial role of such materials in current lithography technology, the effect is now recognized as very significant. The NIST studies explained this phenomenon theoretically and validated the models by measurement. This is world-class work and an important contribution to the photolithography community; it has revealed an important and unexpected optical materials issue in next-generation lithography.

Division work in optical scattering metrology has led to the development of a valuable set of software tools (SCATMECH) for a large class of materials and surfaces. This capability is very relevant for the semiconductor industry and other industrial applications in which process control and process yield require in-depth analysis of subtle surface and subsurface characteristics. The validity of these software tools has been extensively evaluated through laboratory experiments. The software is readily available at a user-friendly Web site (http://www.physics.nist.gov/Divisions/Div844/facilities/scatmech/html/index.htm) and has attracted considerable attention.

In response to pressing national needs, the division has undertaken measurements to assess the viability of spectroscopic detection of biological toxins in sealed envelopes using far-infrared spectroscopy. The rapid action of the division will permit a determination about the suitability and possibility range of application of this noninvasive measurement technique.

Radiometric calibrations of remote sensing satellites and other problems related to environmental monitoring pose new calibration challenges for field instruments. To answer these needs, the Optical Technology Division is developing a new portable instrument, dubbed the Traveling SIRCUS (spectral

Suggested Citation:"5 Physics Laboratory." National Research Council. 2002. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories: Fiscal Year 2002. Washington, DC: The National Academies Press. doi: 10.17226/10510.
×

irradiance and radiance calibration with uniform sources) that will provide a broadly tunable, calibrated laser-based uniform source. Analogous to the SIRCUS instrument currently available at NIST, it will permit the highest-accuracy spectroradiometric calibrations to be performed at remote locations. This represents a significant extension of calibration capabilities in response to user demand.

The production of Standard Reference Materials (SRMs) is a key service offered by the division and used by many customers. SRMs produced include specular and diffuse reflectance and transmittance artifacts, and an infrared wavelength standard. The division also has the capability to make gloss measurements in accordance with the ASTM D253 and ISO 2813 standards. The division hopes soon to add reflective colorimetry and haze measurements to its list of services. The sixth and seventh CORM reports, Pressing Problems and Projected National Needs in Optical Radiation Measurements (www.corm.org/publicat.htm), request more SRMs in numerous areas. The Optical Technology Division plans to offer more calibration services as outlined in SP-250, with faster response, lower cost, and more direct communication between the division and the end user. This effort will also effectively address customer needs that are not being strictly met by existing SRMs.

International key intercomparisons of standards are critical to gathering the information needed to advise U.S. industry on metrology issues worldwide, to providing technical guidance on international memoranda of understanding affecting the U.S. economy, and to advancing the skills of the division. The division is involved in six international key intercomparisons: spectral irradiance, spectral responsivity, luminous responsivity, luminous flux, spectral diffuse reflectance, and spectral transmittance. The division is participating with selected laboratories in a secondary comparison on the measurement of aperture areas, and it is the pilot laboratory for this intercomparison as well as for the reflectance and for segments of the spectral responsivity intercomparisons.

The division is currently running regular short courses in photometry and radiance temperature and hopes to soon offer courses in spectroradiometry. These courses are unique and are, in the panel’s estimate, of great value to the technical community. They give participants a unique opportunity to use state-of-the-art hardware under the supervision of truly competent instructors. A possible complement to these activities would be a series of online courses that could reach a wider audience and could also emphasize standard equipment likely to be found in mainstream laboratory and factory environments.

Division Resources

Funding sources for the Optical Technology Division are shown in Table 5.4. As of January 2002, staffing for the division included 40 full-time permanent positions, of which 35 were for technical professionals. There were also 15 nonpermanent or supplemental personnel, such as postdoctoral research associates and temporary or part-time workers.

Panel members noted that possible reduction in the ATP program may have a significant adverse effect on the budgets of excellent ongoing programs.

Ionizing Radiation Division

Technical Merit

The Ionizing Radiation Division’s mission is to support the NIST mission by providing national leadership in promoting accurate, meaningful, and compatible measurements of ionizing radiations (xrays, gamma rays, electrons, neutrons, energetic charged particles, and radioactivity). The division’s mission statement embraces several activities, ranging from providing standards and reference materials

Suggested Citation:"5 Physics Laboratory." National Research Council. 2002. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories: Fiscal Year 2002. Washington, DC: The National Academies Press. doi: 10.17226/10510.
×

TABLE 5.4 Sources of Funding for the Optical Technology Division (in millions of dollars), FY 1999 to FY 2002

Source of Funding

Fiscal Year 1999 (actual)

Fiscal Year 2000 (actual)

Fiscal Year 2001 (actual)

Fiscal Year 2002 (estimated)

NIST-STRS, excluding Competence

5.5

5.4

5.9

6.2

Competence

1.0

0.9

0.7

0.7

ATP

1.0

1.0

1.1

0.9

Measurement Services (SRM production)

0.1

0.0

0.0

0.0

OA/NFG/CRADA

3.8

4.2

4.2

4.6

Other Reimbursable

0.7

0.6

0.7

0.7

Total

12.1

12.1

12.6

13.1

Full-time permanent staff (total)a

44

46

42

40

NOTE: Sources of funding are as described in the note accompanying Table 5.1.

aThe number of full-time permanent staff is as of January of that fiscal year.

to developing methods and standards and conducting fundamental research. The overall conclusion of this review is that the division continues to accomplish outstanding scientific and technical work and to share its results with the broader scientific community through numerous publications and by participation in and leadership of workshops in topical areas of interest.

The Ionizing Radiation Division is organized primarily according to source technology and consists of three groups: Radiation Interactions and Dosimetry, Neutron Interactions and Dosimetry, and Radioactivity. These groups reflect the division’s involvement in different source-based technologies: gamma and accelerated electrons, neutrons, and radioactive isotopes, respectively. The Radiation Interactions and Dosimetry Group also engages in computational methods and in the development of codes.

The division has taken a more assertive posture in the international standards community through greater involvement in international standards organizations and through interacting more frequently with other national laboratories than in past years.

The Radiation Interactions and Dosimetry Group is involved in four areas of scientific and technical activities: industrial dosimetry, medical dosimetry, protection and accident dosimetry, and theoretical dosimetry. The group provides NIST-traceable dosimetry to the medical and industrial communities and engages in the development of innovative, accurate dosimetry methods and techniques. In support of these uses, the group works on models and codes that increase the accuracy of dosimetry measurements and assist in the application and interpretation of dose and dose distribution in given use areas.

The highlight of the year was the division’s response to the crisis brought about by the use of a bioterror agent, anthrax, in the mail. Ionizing radiation was found to be the most effective way of “sanitizing” contaminated mail and was adopted by the U.S. Postal Service. The Radiation Interactions and Dosimetry Group became extensively involved in calibrating the electron beams (EBs) at the two toll irradiation service centers (which rent EB time and facilities to users) that were contracted by the U.S. Postal Service. Besides providing needed dosimetry and using calculations to show dose distribu-

Suggested Citation:"5 Physics Laboratory." National Research Council. 2002. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories: Fiscal Year 2002. Washington, DC: The National Academies Press. doi: 10.17226/10510.
×

tions, the group developed strong working rapport with the operators of these facilities. The division chief became the coordinator for the interagency task force set up by the Office of Science and Technology Policy (OSTP) to address this issue. The division has thus assumed extensive new responsibilities that include dealing with OSTP, the newly created Office of Homeland Security, and appropriate agencies on a frequent and regular basis. Having expertise and infrastructure in place at NIST as a national resource allowed the division to respond in a timely fashion to this national need.

Industry is accepting the use of spin resonance to read alanine dose effects and is undergoing a transformation to this dosimetric method, which is founded on a stronger scientific basis than are the previously preferred techniques that are based on color changes in radiochromic films. A recent report3 describes a NIST Internet-based “e-calibration” service for these measurements; the service is progressing smoothly. Alanine-coated films from a reputable supplier will help in this transformation process. The acceptance of the technique could be enhanced if the division took the lead in conducting alanine dosimetry intercomparisons among the providers of gamma- and electron-beam services that are used for medical product and food irradiation, as it is doing in “sanitizing” the mail for the U.S. Postal Service. One such study was conducted by the National Physical Laboratory in the United Kingdom and the Risr National Laboratory in Denmark on behalf of the European Union. The study yielded significant empirical results, indicating the precision of alanine as a dosimetry system in the hands of industry and national laboratory experts. This work illustrates the potential long-term impact of improved dosimetric techniques. The division should foster this alanine method by giving it appropriate priority in all areas.

Both the industrial and medical applications rely on the Radiation Interactions and Dosimetry Group for calibrations to a recently refurbished national reference 60Co beam. Given differences in geometry between this beam and an older, weaker 60Co source, some imprecision in dose comparisons between the two beams has been found, requiring characterization of a new 60Co standard therapy source for the calibration program. However, the variation of a few tenths of a percent, depending on dosimeter positioning, may be more than adequate for using the older beam as an alternative source but not as the national reference source for calibrations.

The use of 60Co in medicine as a source for external-beam radiation is rapidly decreasing, so it is essential that NIST develop standards for more conventional complex treatments used routinely in the clinic and prepare to address newer modalities such as intensity modulated radiotherapy with linear accelerators. The division’s plan to acquire a 6- to 20-MeV medical linear accelerator from Varian is noteworthy, in that calibrations could then be made using equipment comparable to that found in the medical community. Attempts to force-fit such calibrations using the old accelerator in the Medical-Industrial Radiation Facility should be abandoned.

Many of the division’s successes are the result of strong theoretical expertise. The division has been a major contributor to today’s major transport codes, through both code development and data archiving. In response to panel recommendations, the division augmented its computational and theoretical expertise by hiring an individual with outstanding credentials in these areas. Although the Radiation Interactions and Dosimetry Group is small, NIST remains one of the few national centers supporting theoretical development and applied calculations in radiation dosimetry. Many of the needed calculations are so specific to standards and calibrations that they are not likely to be done by other research groups or supported by other laboratories because of the lack of expertise in these areas. An example of such work

3  

Desrosiers, M., et al., “e-Calibrations: Using the Internet to Deliver Calibration Services in Real Time at Low Cost,” Radiation Physics and Chemistry 63:759-763, 2002.

Suggested Citation:"5 Physics Laboratory." National Research Council. 2002. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories: Fiscal Year 2002. Washington, DC: The National Academies Press. doi: 10.17226/10510.
×

is that presented in Radiation Protection Dosimetry.4 The method was crucial for the evaluation of doses to the Russian residents exposed in the Techa River area.5 Currently, the group is working on calculations of wall corrections for NIST standard graphite-walled cavity-ionization chambers to determine changes in 60Co, 137Cs, and 192Ir air-kerma standards and on development of relativistic impulse-approximation calculations of Compton scattering of photons from bound atomic electrons (for updating of the NIST photon interaction database). Such calculations are essential for the precise determination of absolute doses and for ensuring the quality of national databases (e.g., NISTIR 6573 [2000]). In today’s scientific climate, such expertise could best flourish if it were more involved in specific end-user and customer issues.

The Neutron Interactions and Dosimetry Group benefits greatly from having a unique, world-class facility to use in its research programs and industry support projects—namely, the cold neutron source at the NIST Center for Neutron Research (NCNR). The group’s activities center on fundamental neutron physics, standard neutron fields and applications, and neutron cross-section standards. The Neutron Interactions and Dosimetry Group provides industrial support for instrument calibration, electric power generation, radiation protection, national defense, radiation therapy, neutron imaging, and magnetic resonance imaging.

The group has performed some of the most precise measurements ever taken of neutron lifetime using an in-beam technique. Measurements were completed for the coherent neutron scattering lengths of hydrogen, deuterium, and 3He. Large-diameter 3He spin filter cells were produced that extended polarization lifetimes. A 0.9-nm neutron monochromator was developed and tested for ultracold neutron production. This group was also responsible for producing and implementing a set of high-quality B-10 depositions used as part of a new international intercomparison for thermal neutron fluence rates. The group has developed a new cryogenic calorimeter for direct lifetime measurements; it is used to recalibrate the National Standard Neutron Source more accurately. Some of the applications arising from the fundamental work of this group include a neutron spectrometer that will be used for homeland defense research and a 3He laser polarization measurement technique that has potential as a low-cost imaging technique for medical applications.

The group’s interaction with diverse collaborators from the academic community and from other government laboratories remains strong, and its rate of publication remains high. The success of NIST researchers and collaborators in obtaining peer-reviewed support speaks of the importance and quality of the work from this group. Its activities in the area of neutron dosimetry have demonstrated leadership in national and international forums. Involvement with national laboratories in Germany and the United Kingdom in dealing with intercomparisons of thermal neutron fluence measurements is noteworthy.

The Radioactivity Group continues to be involved in four principal areas of scientific and technical activities: standards and methods, metrology in nuclear medicine, metrology and monitoring related to the environment, and quality assurance and traceability. This group is largely responsible for establishing and maintaining the primary standards for radioactive counting. The group focuses on preparing radioactive standards SRMs, developing calibration methods, and providing NIST traceability to cus-

4  

Seltzer, S.M., A.A. Romanyukha, and V. Nagy, “Monte Carlo Calculations of the Dose Distribution in Teeth Due to Internal Exposure from 90Sr: Application to EPR Tooth Dosimetry,” Radiation Protection Dosimetry 93:245-260, 2001.

5  

Romanyukha, A.A., S.M. Seltzer, M. Desrosiers, E.A. Ignatiev, D.V. Ivanov, S. Bayankin, M.O. Degteva, F.C. Eichmiller, A. Wieser, and P. Jacob, “Correction Factors in the EPR Dose Reconstruction for Residents of the Middle and Lower Techa Riverside,” Health Physics 81:554-566, 2001.

Suggested Citation:"5 Physics Laboratory." National Research Council. 2002. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories: Fiscal Year 2002. Washington, DC: The National Academies Press. doi: 10.17226/10510.
×

tomers in fields ranging from nuclear medicine and radiopharmaceuticals to environmental monitoring and nuclear power. As a result, it is very customer oriented.

In addition to maintaining and disseminating the primary standards for radioactivity, the group characterizes reentrant ionization chambers, or “dose calibrators,” as secondary standards for nuclear medicine; evaluates and remeasures nuclear decay properties; and performs work designed to exercise and maintain its expertise in radiochemistry and analysis methodology. Its evaluation of 5 alpha spectrometry analysis algorithms to resolve overlapping peaks for 241Am and 243Am under typical low-level counting conditions was accepted for publication in Applied Radiation and Isotopes. Its recently published work in the Journal of Radioanalytical and Nuclear Chemistry,6 describes an alternative statistical approach for the evaluation of interlaboratory comparison data.

The group provides measurement and calibration support for the development of standards and metrology for nuclear medicine, including new and existing radioimmunotherapy agents and devices. Considerable progress has been made over the past year in developing quantitative destructive assay techniques for pure beta emitters such as 32P used in coronary stents and as intravascular brachytherapy sources in balloon angioplasty, as well as for 90Sr-90Y “seeds” also used for intravascular brachytherapy. Careful attention to detail by the experimenter enabled the development of a protocol that accounted for all possible losses during destructive chemical processing, including those in the chemical- and source-handling steps. The determinations of activity from this work serve two purposes. First, the activity measurement provides a “primary” standard that can be used to calibrate nondestructive “secondary” measurement methods using ionization chambers. Second, given the activity of a sample, radiochromic film measurements of the spatial distribution of the absorbed dose of the sample can be related to theoretical Monte Carlo dose calculations. The results for the destructive assay work for both the 90Sr-90Y “seeds” and the 32P angioplasty balloon catheter sources have been published in Applied Radiation and Isotopes.7

Other notable efforts in the area of nuclear medicine metrology include a very extensive and methodical set of experiments to determine the effects of factors such as solution pH and ionic strength, the presence of chelators, and the choice of commercial scintillants on the accuracy of assays performed with the liquid scintillation (LS) technique. In addition, a new initiative is under way to assemble and evaluate a Triple Double Coincidence Ratio (TDCR) system that will obviate the need for tritium efficiency tracing. The TDCR was initially developed and demonstrated in France, and the Radioactivity Group should be commended for working in collaboration with French counterparts to bring this technology to NIST. Both of these efforts are timely and important, because LS is the preferred measurement method used by most laboratories, including NIST, for the quantitative assay of pure beta-emitters.

Metrology efforts associated with personnel and environmental monitoring require the ability to measure radionuclides at very low levels, and, as a result, much of the work in this area involves careful sample handling and preparation under highly controlled conditions in a clean-room facility. To provide closely matched standards to meet user needs, the Radioactivity Group engages in developing and characterizing “natural matrices” such as soils, sediments, biota, and biological systems contaminated

6  

Inn, K.G.W., et al., “Standards, Intercomparisons and Performance Evaluations for Low-Level and Environmental Radionuclide Mass Spectrometry and Atom Counting,” Journal of Radioanalytical and Nuclear Chemistry 248:163-173, 2001.

7  

Collé, R., “On the Radioanalytical Methods Used to Assay Stainless-Steel Encapsulated, Ceramic-Based 90Sr-90Y Intravascular Brachytherapy Sources,” Applied Radiation and Isotopes 52:1-18, 2000; Collé, R., “Calibration of 32P ‘Hot-Wall’ Angioplasty-Balloon-Catheter Sources by Liquid-Scintillation-Spectrometry-Based Destructive Radionuclidic Assays,” Applied Radiation and Isotopes 54:611-622, 2001.

Suggested Citation:"5 Physics Laboratory." National Research Council. 2002. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories: Fiscal Year 2002. Washington, DC: The National Academies Press. doi: 10.17226/10510.
×

with naturally occurring radionuclides from the decay of uranium or thorium or by actinides and fission products resulting from human activities. Of particular note are the ongoing efforts associated with the 2nd Intercomparison Study for Detecting µBq Quantities of 239Pu in Urine by Atom Counting. This work, which directly supports the DOE program to resettle the Marshall Islands, is comparing four different atom-counting techniques—inductively-coupled plasma mass spectrometry, fission track analysis, accelerator mass spectrometry, and thermal ionization mass spectrometry—to determine the best technique(s) for quantifying Pu at or below the 20 µBq/L level. Three organizations—the University of Utah, LLNL, and LANL—are participating in this intercomparison and are being given “realistic” bioassay samples that contain 239Pu, environmental levels of 240Pu, and natural uranium. The results of the first intercomparison have been published in the Journal of Radioanalytical and Nuclear Chemis-try,8 and results of the second study are expected out in 2002. A follow-on, third intercomparison study is being planned. The next study is expected to be considerably broader and will include the absolute determination of amount and isotopic composition of both U and Pu in a wide range of matrices. This effort has obvious applications and will provide a needed exercise and evaluation of laboratories involved in assays related not only to occupational health programs but to nuclear nonproliferation and counterterrorism as well.

NIST is investigating the use of resonance ionization mass spectrometry (RIMS), with glow discharge atomization and CW laser excitation to measure long-lived, low-energy beta and x-ray emitting radionuclides that are not easily measured with conventional radiometric techniques. Because this technique holds the potential for both high selectivity and high efficiency, RIMS is expected to significantly reduce the time required for determination of absolute activity by completely bypassing the need for lengthy radiochemical separation procedures. Further, RIMS offers the advantage of measuring several isotopes simultaneously and being independent of the nuclear decay properties. Consequently, maintaining a viable and robust RIMS capability would reduce costs to customers for these types of analyses. Currently, RIMS is being evaluated for the determination of low levels of 135Cs and/or 137Cs in the presence of stable 133Cs. Optical selectivity of 103 for 135Cs and 137Cs against 133Cs was observed, and measurements on subpicogram samples have been demonstrated. Plans for the future include evaluating RIMS for the detection and measurement of Pu isotopes and atom trapping to achieve single-atom detection.

The Radioactivity Group has made considerable progress during the past year toward bringing online its double-focusing thermal ionization mass spectroscopy (TIMS) unit. Eventually this system will be the workhorse for providing accurate and precise measurements for both the total amount and the isotopic composition of samples containing ultralow levels of Pu. The applications for this capability are primarily for determining the environmental transport of Pu involved in site remediation efforts, bioassays, and treaty verification measurements in support of nuclear test ban and nonproliferation national security activities. Currently, efforts are ongoing to determine and optimize filament loading techniques, to push down the sensitivity to the desired level of 106 atoms. At the present time, the division has demonstrated the 109 atom level.

The storage photo-stimulable phosphor (SPP) imaging plate system is being evaluated as a means for determining and quantifying the distribution of radionuclides over large-area surfaces. To date, its usefulness for mapping the location of ultralow levels of radioactivity has been demonstrated, but its

8  

Inn, K.G.W., et al., “Intercomparison Study of Inductively Coupled Plasma Mass Spectrometry, Thermal Ionization Mass Spectrometry and Fission Trace Analysis of mBq Quantities of 239Pu in Synthetic Urine,” Journal of Radioanalytical and Nuclear Chemistry 248:121-131, 2001.

Suggested Citation:"5 Physics Laboratory." National Research Council. 2002. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories: Fiscal Year 2002. Washington, DC: The National Academies Press. doi: 10.17226/10510.
×

ability to quantify activity levels reliably and accurately has not yet been proven. However, this technique is being evaluated for possible use in measuring ultralow releases of 40K from the degradation of concrete in bridge abutments.

The consolidation of the gamma-ray systems into one location and the conversion from an old, custom UNIX-based data acquisition system to a new, networked Windows-based, commercially available data acquisition system has been successfully completed. No adverse impacts were noted during the transition, and all of the detectors are now operable and intercalibrated over the appropriate energy ranges.

Over the past year the Radioactivity Group has made great strides toward reestablishing NIST as a world leader in radiometric calorimetry. In response to panel concerns, the dual-compensated cryogenic calorimeter—designed to operate at 8 K and to measure the absolute activity of nuclides that decay by pure beta emission and electron capture—has been upgraded. Substantial improvements have been made to the cryostat vacuum system, and additional modifications have been identified that are expected to improve the baseline stability and considerably reduce the parasitic heat losses between stages. The results of the work on the cryogenic calorimeter were presented at the most recent meeting of the International Committee for Radionuclide Metrology (ICRM) and have been accepted for publication in Applied Radiation and Isotopes. The group also installed and evaluated a new commercial isothermal microcalorimeter that operates at 303.5 K. Of particular note were modifications made to the microcalorimeter to allow absolute, NIST-traceable power measurements by incorporating specially designed and calibrated resistive heating elements within the source cell. Additionally, very meticulous efforts to calibrate the microcalorimeter over the power range from 15 to 250 µW for several sample holder configurations enabled calorimetric measurements of 90Sr-90Y brachytherapy seeds and a 32P “hot wall” angioplasty-balloon-catheter and comparison with the results from destructive assay and ionization chamber methods. It is interesting to note that for the 32P balloon catheter, excess heat was detected and identified as resulting from chemical reactions induced by the interaction of beta particles with the material composing the balloon. When this correction was applied, the “correct” value for the heat resulting from radioactive decay was obtained.

Program Relevance and Effectiveness

The Ionizing Radiation Division is a relatively small national laboratory in comparison with other federal laboratories, but its past successes and its future lie in maintaining and fostering a proper balance and synergy between expertise in basic research (where payoffs are usually both distant and uncertain) and calibrations, standards, and quality assurance (where dramatic discoveries or events are rare). Having in place a credible dosimetry system based on alanine enabled the division to respond to the use of electron beam irradiation as the select process for “sanitizing” presidential, congressional, and other mail from the anthrax threat. This exemplifies the need for maintaining expertise and resources and supporting developmental work in major areas of radiation research and technologies in order to deal with new developments and unexpected events.

The division maintains strong participation in national standards organizations, such as ASTM International, the American National Standards Institute, Digital Imaging and Communications in Medicine, and the Institute of Electrical and Electronics Engineers (IEEE). In response to previous panel suggestions, the division has enhanced its involvement in the international standards community though the International Commission on Radiation Units and Measurements, the International Electrotechnical Commission, and the International Committee for Radionuclide Metrology. Division personnel are members of key professional associations, such as the American Association of Physicists in Medicine

Suggested Citation:"5 Physics Laboratory." National Research Council. 2002. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories: Fiscal Year 2002. Washington, DC: The National Academies Press. doi: 10.17226/10510.
×

and the Health Physics Society, and of national bodies such as the National Council on Radiation Protection and Measurements and the Council on Ionizing Radiation Measurements and Standards (CIRMS). The division has been attentive to national needs as spelled out by CIRMS, an independent, nonprofit coordinating council that draws its constituents from industry, academia, and government, and it assisted CIRMS in publishing its third triennial report on National Needs in Ionizing Radiation Measurements and Standards.9 It is through these various organizations and through its direct contact with the scientific and industrial communities that the division stays abreast of current activities and is a key contributor in the fields of ionizing radiation measurements and standards.

The panel noted in its previous report that the medical and industrial communities require more frequent updates on developments and issues involving calibrations and dosimetry determinations, perhaps by means of status reports posted quarterly on the NIST Web site. For example, user community concerns over variances in air-kerma calibrations could be more readily calmed by more frequent communication. In some areas, the user community could benefit by division personnel assuming positions of leadership in organizations such as ASTM.

The Neutron Interactions and Dosimetry Group enjoys excellent industrial and academic collaboration, predicated on having use of a world-class facility, the ultracold neutron source of the NCNR and complementing this with outstanding nondestructive analytical capabilities such as the Neutron Interferometry and Optics Facility. These tools have enabled the group to engage in projects on the cutting edge of small-scale power generation: analysis of fuel cell membranes and investigations into ion transport in lithium batteries. The group also has excellent rapport with the nuclear power industry. The group performs an outstanding job of balancing these industrial concerns with fundamental research. However, the fundamental research projects are quite complex. The panel noted last year that generating an overview of these projects, including milestones passed and milestones expected, would benefit their management and assessment.

The Radioactivity Group responds well to its customer base but should be cautious in taking on efforts that overextend the group’s resources. In this regard, a review of existing and needed SRMs should be made to enable a clearer delineation of the amount of effort and resources needed to support these SRMs. In fact, given the endless possibilities of generating SRMs based on various radionuclides, soils, and other contaminants, the division as a whole should develop a list of the most-needed SRMs and a justification for providing them, relying on some cost-benefit analysis.

The group is to be commended on its completion of a 4-year endeavor on the NIST Radiochemistry Intercomparison Program (NRIP) that provided measurement traceability for low-level environmental measurements in accordance with the acceptance criteria as defined in ANSI-N42.22, “Traceability of Radioactive Sources to NIST and Associated Instruments Quality Control.”

The division continues to support as well as develop new quality-assurance programs for federal, military, and private organizations, as requested. This effort includes setting standards, establishing and validating traceability programs, performing instrument calibrations, and participating in intercomparison programs. Currently, division customers include but are not limited to the Food and Drug Administration (FDA), the U.S. Army, the U.S. Air Force, the Department of Energy (DOE) and its associated national laboratories, the U.S. Nuclear Regulatory Commission, and the nuclear medicine and power industries through the Nuclear Energy Institute.

9  

National Needs in Ionizing Radiation Measurements and Standards. CIRMS, October 2001. Available online at <http://www.cirms.org/NR3info.htm>.National Needs in Ionizing Radiation Measurements and Standards. CIRMS, October 2001. Available online at <http://www.cirms.org/NR3info.htm>.

Suggested Citation:"5 Physics Laboratory." National Research Council. 2002. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories: Fiscal Year 2002. Washington, DC: The National Academies Press. doi: 10.17226/10510.
×

The division’s theoreticians are probably the only body of researchers in the United States committed to the theoretical aspects of standards and calibrations. This provides indispensable support for the division’s experimentalists. A recent reduction in staffing for this effort was of concern, but the panel is pleased to see that a new staff member has been added. To be most effective, this effort now requires well-defined strategy and goals.

Among the division’s homeland security proposals, the development of a national program for the assurance of security x-ray inspection systems is within NIST’s proper charter. Such a measurement quality assurance (MQA) is warranted, given the proliferation of security x-ray systems. Caveats should be clearly expressed to others in government and at NIST on the limits of x-rays to detect certain materials—that is, plastic-like explosives, composite cutting tools, and so on—that terrorists have selected as materials of choice.

The division is to be commended on its intent to acquire a medical linear accelerator for use in developing standards for patient treatments and its studies of dosimetry and materials effects. It is unfortunate that it took a national calamity to compel the division to put forth a proposal for a state-of-the-art accelerator facility, its Irradiation Testbed Facility (ITF), as noted in one of its homeland security proposals. Given ITF’s costs, the division would show prudence by preparing an alternate plan for certifying a state-of-the-art, high-current industrial electron-beam accelerator as a reference source. This might be most useful if done in collaboration with a university.

The division possesses outstanding expertise and facilities in the neutron area, and its resources might be better used in leading and coordinating activities centering on neutron systems for sensing explosives, contraband, and nuclear materials with other national laboratories rather than replicating well-established efforts that have been in progress for many years elsewhere. As in its work with the U.S. Postal Service, NIST and the Ionizing Radiation Division best serve national interests by being a resource of expertise and a neutral facilitator. Such expertise in coordinating and facilitating programs could be brought to bear in the neutron detector area and would be of greater value than attempting to develop specific instrumentation.

Division Resources

Funding sources for the Ionizing Radiation Division are shown in Table 5.5. As of January 2002, staffing for the division included 38 full-time permanent positions, of which 34 were for technical professionals. There were also 3 nonpermanent or supplemental personnel, such as postdoctoral research associates and temporary or part-time workers.

Attrition and retirements have enabled the division to attain a more balanced age profile. The division is to be commended for bringing very bright junior scientists onto its staff.

While the division will benefit from personnel transfers to support its involvement in homeland security issues, this may not compensate for a declining budget for the division’s core operations, particularly if the costs of additional responsibilities are to come in part from existing budgets. While competitive funding from other federal agencies, such as DOE, can enhance the quality of programs, the division itself should have a strong enough base budget to sustain its essential role in measurements and standards.

CIRMS has expressed concerns over adequate division staffing as the council develops Measurement Program Descriptions (MPDs) that are intended to express to the division national needs in radiation measurements and standards. The growing demands in the medical area and emerging issues such as food irradiation warrant staff support as well as needs in the area of occupational radiation

Suggested Citation:"5 Physics Laboratory." National Research Council. 2002. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories: Fiscal Year 2002. Washington, DC: The National Academies Press. doi: 10.17226/10510.
×

TABLE 5.5 Sources of Funding for the Ionizing Radiation Division (in millions of dollars), FY 1999 to FY 2002

Source of Funding

Fiscal Year 1999 (actual)

Fiscal Year 2000 (actual)

Fiscal Year 2001 (actual)

Fiscal Year 2002 (estimated)

NIST-STRS, excluding Competence

4.5

4.3

4.3

5.3

ATP

0.2

0.2

0.2

0.0

Measurement Services (SRM production)

0.1

0.1

0.1

0.1

OA/NFG/CRADA

1.6

1.5

1.7

2.2

Other Reimbursable

0.9

1.2

1.4

1.4

Total

7.3

7.3

7.7

9.0

Full-time permanent staff (total)a

36

33

38

38

NOTE: Sources of funding are as described in the note accompanying Table 5.1.

aThe number of full-time permanent staff is as of January of that fiscal year.

protection. The division, as does industry in general, faces the difficulty of finding recruits with adequate background in nuclear chemistry and radiochemistry. The division could help address this nationwide talent shortage by working in cooperation with the American Chemical Society and with a supportive organization such as CIRMS to give presentations to undergraduates on the merits and challenges involved in radiation science and technology.

Within the operational practices at NIST, the Ionizing Radiation Division (and perhaps other divisions as well) could benefit by having an adequate equipment repair and maintenance budget under the discretion of the division chief, but independent of the research, standards, and calibration budgets. For example, x-ray calibrations had to be suspended for more than 4 months, not only until a replacement x-ray generating tube could be found but also while internal budget funds were sought to acquire it. There should be a budget strategy for routinely replacing and decommissioning outdated equipment.

With the expanding numbers of applications of brachytherapy, the growing acceptance of seed implantation as a method for treating prostate cancer and other malignancies, and the involvement of a greater number of potential suppliers and diverse sources and configurations, the division’s resources for seed and other brachytherapy calibrations are being strained. Recent responsibilities include the establishment and maintenance of air-kerma-strength standards for new prostate seeds, including the transfer of standards to secondary laboratories and the characterization of transfer instrument (wall-ionization chambers) response. Recognizing the importance of strong input and oversight by NIST scientists, the division should take a close look at how much of this calibration work can be turned over to ADCLs or secondary standards laboratories.

Given its shift in priorities and emphasis, the division might wish to consider realigning its resources into groups centered upon its customer base: the medical area, the industrial area, and the occupational and radiation protection areas, instead of being aligned by source technology. This would be comparable to the way in which CIRMS has organized its scientific and technical committees and should enable the division to be more responsive to its customers.

Suggested Citation:"5 Physics Laboratory." National Research Council. 2002. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories: Fiscal Year 2002. Washington, DC: The National Academies Press. doi: 10.17226/10510.
×

Time and Frequency Division

Technical Merit

The mission of the Time and Frequency Division is to support the NIST mission through the provision of measurement services and research in time and frequency and related technology to U.S. industry and science. The division is organized in four technical groups: Time and Frequency Services, Atomic Standards, Ion Storage, and Optical Frequency Measurements. The groups are small, and the group leaders function primarily as technical leaders within their areas. The common theme of time and frequency technology produces a strong connection among the groups, and there are positive interactions among them.

The Time and Frequency Division continues to define the international state of the art in current-day time and frequency standards and services and in the long-range development of improved standards and services. In the past year, the division realized a major goal of research carried out over the last two decades—an optical frequency standard using trapped ions. More details of this accomplishment are given below.

The cesium fountain standard, NIST-F1, has now supplanted the cesium beam standard, NIST-7, as the primary time standard. The frequency uncertainty of NIST-F1 was improved in the past year from 1.7 × 10−15 to 1.2 × 10−15. This latter evaluation is the best ever reported by any laboratory to the Bureau International des Poids et Mésures (BIPM). This improvement was made possible by more closely controlling light shifts, keeping the number of atoms in each bunch constant, and incorporating a better quartz flywheel oscillator and new software for the line center servo. In the near future, diode lasers will be replaced by a Ti:sapphire laser for further improvement. The division is working on improvement in the reliability of NIST-F1 to provide more regular data that will preserve NIST-F1’s weight in the BIPM time scale.

Improvements to the fountain technique are being carried out in parallel with the operation of the NIST-F1 standard. In part, these advances are made possible by the existence of parallel programs. In particular, NIST has built a transportable fountain clock, in which the Cs atoms are not thrown as high and the atom cloud does not expand as much, so the signals are larger than those of NIST-F1, allowing quicker comparisons of clocks. Using this clock, the division is investigating transverse cooling of the tossed atoms with the goal of improving the number of detected atoms.

Design and construction of the next-generation cesium fountain clock, NIST-F2, have begun with several improvements. NIST-F2 might have no on-axis lasers, thereby avoiding light shift effects; the interrogation region will be cooled to liquid nitrogen temperature to eliminate the uncertainty of the black body shift (currently 3 × 10−16); and NIST-F2 will also use an improved transverse cooling technique.

The division is participating in a NASA-led consortium to build a Primary Atomic Reference Clock in Space (PARCS), based on laser-cooled Cs atoms. One of the requirements peculiar to these very low atomic velocity clocks is immunity to vibration. To minimize the sensitivity of the clock to vibration, a phase modulation of the second Ramsey field is employed rather than the usual technique of switching the frequency back and forth between opposite sides of the central fringe. This technique has other advantages—reduced line pulling and cavity pulling effects—which have led to its use on NIST-F1.

The Optical Frequency Measurements Group continues to ride the wave of momentum and opportunities created by the demonstration of an optical frequency comb. Femtosecond pulses from a mode-locked laser are injected into a nonlinear microstructure fiber and emerge as periodically spaced phase-coherent modes spanning an octave of frequency. By frequency doubling a low-frequency mode and

Suggested Citation:"5 Physics Laboratory." National Research Council. 2002. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories: Fiscal Year 2002. Washington, DC: The National Academies Press. doi: 10.17226/10510.
×

FIGURE 5.2 Improvement in frequency uncertainty of optical frequency measurements.

comparing it with a high-frequency comb mode, it is possible to connect the pulse repetition frequency of the mode-locked laser to the frequencies of the comb modes in a phase-coherent way. If the pulse repetition frequency is phase-locked to a stable reference, such as a hydrogen maser, the frequency of every mode in the comb is then known with the precision of the frequency of the reference. Such a system allows any frequency in the spectral range of the comb to be measured with the uncertainty of a primary frequency standard.

The dramatic recent improvement in the accuracy of optical frequency measurements is shown in Figure 5.2. It is not an exaggeration to state that this approach is revolutionizing the strategy for next-generation primary frequency standards. Standards and clocks much better than the current primary standard should be realized in the next decade.

To date, frequency combs have been produced with a center wavelength of 800 nm using Ti:sapphire lasers. It is highly desirable to extend this approach to the optical-fiber communication bands at 1.3 and 1.55 µm for telecommunications applications. The specific goal is to support wavelength-division multiplexing. The division has begun design and assembly of a mode-locked Cr:forsterite laser that emits ~1.3 µm. This is referenced to the 657-nm line of calcium after division by 2. Significant applications of the femtosecond comb to measurements of atomic frequencies were also demonstrated in the past year. For example, the 282-nm transition of a single Hg+ ion and the 657-nm transition of a calcium ion were measured with the frequency comb, and the measurements are now limited by the uncertainty in the frequency of the primary cesium standard.

In the summer of 2001, the Time and Frequency Division passed a major milestone—the demonstration of an optical frequency standard with a microwave output—which was made possible by the frequency-comb work. The resultant clock benefits from the high Q (the ratio of transition frequency to linewidth) of an optical transition, the cycle-counting capabilities that exist at microwave frequencies, and the translation of the extreme performance of optical frequency standards to the microwave range provided by an optical frequency comb. A 282-nm optical frequency standard with Q ~ 1014 (a single trapped Hg+ ion) is coupled to a frequency comb that bridges an octave in the optical spectrum. As described above, the phase-locking of comb modes spaced ~1 GHz apart produces a phase-coherent

Suggested Citation:"5 Physics Laboratory." National Research Council. 2002. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories: Fiscal Year 2002. Washington, DC: The National Academies Press. doi: 10.17226/10510.
×

pulse train at that repetition rate. Thus, a microwave output phase-locked to the optical frequency standard is obtained. This device has a frequency stability of 7 parts in 1015 with a 1-second averaging time and has the potential to achieve uncertainties 1,000 times better than those of the current best standards.

Other avenues for more sophisticated clocks based on atom entanglement are being pursued. In a standard clock, with no systematic shifts and with uncorrelated atoms, the projection noise decreases as the square root of the number of atoms. If the atoms can be entangled, the projection noise can decrease directly as the number of atoms; this improvement has been demonstrated using two trapped ions. Entanglement also allows the use of ions with good clock transitions but no suitable readout transitions. Specifically, efforts are under way to explore the use of two trapped ions: one, the “clock ion,” has a high Q transition, and the other, the “logic ion,” is used to read the state-of-the-clock ion. The coupling between the two is via the vibrational modes of the ions in the trap.

While originally pursued by NIST for its possible applications to clocks, the use of atom entanglement for quantum computing is now being investigated by the division. Two significant advances were made in the past year. First, the dominant source of decoherence in the atom trap was found to be patch electrostatic fields arising from Be coating the trap electrodes. Improved shielding of the electrodes from the Be source has reduced the patch fields by a factor of 30, allowing ions to remain coherent for a correspondingly longer time. It appears to be difficult to store a sufficient number of ions in the trap at one time in order to make a quantum computer with 10 or more qubits. Instead, the proposed approach is to shuttle ions into and out of a computing region. A central question is whether or not the ions, which are in superposition states, will maintain their coherence. In its second advance of the past year, NIST has demonstrated that they do maintain coherence. It is noteworthy that the NIST approach to quantum computing is the only one currently being pursued that is scalable in size.

The calcium optical frequency standard, based on a narrow resonance in calcium atoms that are laser-cooled and trapped in a magneto-optical trap, has very good short-term stability (currently 4 × 10−15 at 1 second), limited primarily by the atomic velocity. Due to its lower Q (by 2 orders of magnitude), it does not appear to be a serious competitor to the mercury ion standard for use as a primary standard, but it is useful for comparisons of optical standards. In the past year, the temperature of the calcium ions was reduced to 4 µK (from 1 mK) by a quenched narrow line cooling approach. The cooling will be extended to three dimensions, which should result in a factor-of-30 reduction in the atomic velocity and a substantially improved clock.

DARPA has expressed interest in development of a low-power chip-scale clock with a total volume of 1 cm3. Theory and experimental demonstrations at NIST confirm the feasibility of such chip-scale clocks. In one scheme, coherent population trapping is used to eliminate the necessity for a microwave cavity, thereby enabling major reductions in size. Instead, the light from a laser diode is frequency-modulated at half the Cs hyperfine spacing. When the modulation frequency is precisely half the hyperfine spacing, the optical transmission is maximized. Locking the microwave frequency to the maximum transmission gives a clock with performance comparable to an Rb gas-cell clock and several orders of magnitude better than the best quartz oscillator. With DARPA support, it is quite likely that a small-size, low-power, and moderately good performance, gas-cell clock will be developed and adopted for commercial manufacture. Such a clock will generate breakthrough applications for military and commercial telecommunications use.

The stability of the NIST coordinated universal time (UTC) time scale with respect to the UTC disseminated by BIPM continues to improve, most recently through the use of five commercial hydrogen masers with cavity autotuning. Improvements in the comparison of time scales have been achieved by application of two-way time transfer and carrier phase common view techniques. The division has

Suggested Citation:"5 Physics Laboratory." National Research Council. 2002. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories: Fiscal Year 2002. Washington, DC: The National Academies Press. doi: 10.17226/10510.
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also produced a special time scale, AT1E, which is very useful for comparing frequency standards at very high precision over extended periods of time. It also added a new comparison and measurement system at 100 MHz to enable better measurements of local high-performance frequency standards.

NIST defines the state of the art in the construction of microwave-frequency synthesizers for the primary frequency standards. Most new standards have or will have NIST-built synthesizers. NIST has now delivered 10 copies of its microwave synthesizer for frequency standards. These are carefully designed to have low phase noise (roughly 20 dB below commercially available synthesizers) and very high phase stability with ambient temperature changes. The most dramatic improvement in performance in the past year was the reduction of the temperature coefficient to 0.1 ps/K. It is noteworthy that these synthesizers have a basic architecture that supports generation of interrogation signals for cesium (9.192 GHz), rubidium (6.834 GHz), hydrogen (1.414 GHz), and mercury (40.5 GHz). To avoid taxing limited staff resources, the division should investigate whether construction of these sources can be assumed by a commercial partner.

Efforts are ongoing to develop phase and amplitude noise measurement capability and techniques at frequencies up to 100 GHz. This regime, far beyond the range of commercial instrumentation, has applications in high-speed digital devices, broadband telecommunications, and radar. Using external funding, the division has worked to develop techniques for and to perform phase noise measurements of pulsed radar signals. The division’s capabilities in these areas are unique in the world.

Time transfer via GPS common view techniques, including carrier phase, and two-way satellite transmission remains at the state of the art. The division has demonstrated the world’s best frequency comparison via time transfer at 5 × 10−16. The rapid advance of the accuracy and stability of primary frequency standards is stressing the capability of international frequency comparison via these techniques. This continues to be a highly important area for work and innovation, and such work is in the division’s plans.

The service functions of the division are focused primarily in the Time and Frequency Services Group and include telephone and network time messages and radio transmissions from WWV, WWVB and WWVH. The Internet servers at NIST now handle traffic of 350 million hits a day and continue to grow at 8 percent per month.

Program Relevance and Effectiveness

The Time and Frequency Division provides technology-specific services as well as fundamental research in these areas of technology.

In the view of the panel, the most important division product is its outstanding research in the science and technology of atomic frequency standards. This is work that has enormous leverage in the hands of scientists and engineers engaged in new product development in industry. The success of the division in responding to this need is demonstrated by its 83 publications and 71 invited talks in 2001. The division also organized six tutorials or workshops in 2001, teaching time and frequency science, technology, and techniques.

In March 2001, the division hosted a workshop on chip-scale atomic clocks. Theoretical work by division scientists has become the enabling basis for proposed atomic clocks with unprecedented small size (1 cm3), low power (30 mW), and performance (1 × 10−11 at 1 hour averaging time). The division is working to confirm and expand the understanding of the physics of these miniature clocks, which would have defense applications of significant impact. The division should evaluate, by informal survey or otherwise, the time and frequency industry’s interest in topic-specific workshops with the goal of having one such workshop each year. The objective is to transfer NIST knowledge and technology to U.S. industry more efficiently. One suggested topic is “RF carrier cancellation techniques.”

Suggested Citation:"5 Physics Laboratory." National Research Council. 2002. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories: Fiscal Year 2002. Washington, DC: The National Academies Press. doi: 10.17226/10510.
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The accuracy of NIST-F1 is the world’s best data submitted to the BIPM at 1.2 × 10−15. The interplay of the time scale, the primary frequency standards, and the precision time transfer programs are synergistic with multiple, yet coordinated, objectives. The precision time transfer programs allow intercomparison with other international laboratories; the time scale provides a continuous and stable reference; and the primary standards provide the ultraprecision data points, which serve to calibrate the time scale. Regular and periodic evaluations of the primary standards, necessary to represent NIST performance in the international BIPM time scale, is a challenge to division staff. In order to preserve the standing of the NIST primary frequency standard in the international BIPM time scale, the panel recommends that the division adopt an approach to primary frequency standard design that allows a more continuous evaluation.

It is noteworthy that the division is in the process of upgrading the time scale measurement system that is the backbone of the time scale, replacing 20-year-old equipment that is exhibiting both performance and reliability issues.

The increased radiated power from WWVB has made a reality of the availability of accurate (<1 second error), very low cost wall clocks and wristwatches that reset automatically to the WWVB signal. Signal strengths of 100:V/m, upon which these clocks rely, are now available throughout the continental United States. Because of its limited resources, the division should prepare a cost-benefit analysis for the operation of WWV and WWVH transmissions, with the goal of eventual discontinuation of services that offer limited benefit to the United States.

Traffic at the division’s Internet time service (www.boulder.nist.gov/timefreq/service/its.htm) continues to grow, seemingly without bound, reaching 350 million hits per day and growing at 8 percent per month, as stated above. The view of the panel is that continued expansion of this service represents an unjustifiable load on division resources. More aggressive efforts should be made to move this to industry, in accordance with the multitier calibration capability structure more common in other calibration functions in the United States. As a last resort, the option should be considered of consciously limiting future expansion of support for this service, with an anticipated degradation in quality of service. Continuation of the free NIST service may have perceived aspects of competition with industry.

Division Resources

Funding sources for the Time and Frequency Division are shown in Table 5.6. As of January 2002, staffing for the division included 35 full-time permanent positions, of which 30 were for technical professionals. There were also 6 nonpermanent or supplemental personnel, such as postdoctoral research associates and temporary or part-time workers.

In an environment of nearly level funding, the division must adopt a strategy that responds accordingly. It is important to actively select roles to embrace and those to defer, since there will never be enough resources to do everything. This should not be taken as a suggestion that activities be terminated. In fact, it is difficult to identify activities of the division that are not worthwhile. Rather, the panel suggests exploring alternative methods for delivering some of the division’s services, so that the expertise of the division can be focused on its long-term goal of providing continually improving standards.

The division continues to attract and retain high-quality personnel. A strength is the management system under which individual scientists are encouraged to show initiative. The division is staffed at a level sufficient to continue good progress on scientific and technical projects, and overall, the division is reasonably well supported. However, enough outstanding ideas and projects exist in the division to

Suggested Citation:"5 Physics Laboratory." National Research Council. 2002. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories: Fiscal Year 2002. Washington, DC: The National Academies Press. doi: 10.17226/10510.
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TABLE 5.6 Sources of Funding for the Time and Frequency Division (in millions of dollars), FY 1999 to FY 2002

Source of Funding

Fiscal Year 1999 (actual)

Fiscal Year 2000 (actual)

Fiscal Year 2001 (actual)

Fiscal Year 2002 (estimated)

NIST-STRS, excluding Competence

6.0

6.0

6.1

5.9

Competence

0.0

0.1

0.6

0.5

ATP

0.1

0.1

0.2

0.2

OA/NFG/CRADA

2.6

2.5

2.8

3.6

Other Reimbursable

0.6

0.9

1.0

1.0

Total

9.3

9.6

10.7

11.2

Full-time permanent staff (total)a

40

39

39

35

NOTE: Sources of funding are as described in the note accompanying Table 5.1.

aThe number of full-time permanent staff is as of January of that fiscal year.

keep a significantly larger staff very productively engaged. Management of the division is excellent; morale is high, and the staff enjoys a real sense of advancing the state of the art and enjoying the fruits of many years’ worth of discovery and development as well as taking advantage of unexpected new techniques and opportunities.

University research in frequency and time standards is by now nearly nonexistent in the United States. As a result, NIST, through its postdoctoral programs, has become the best place for a promising physicist to learn the science and technology of atomic frequency standards. The National Research Council’s postdoctoral program is the most visible of the NIST postdoctoral programs, and two NRC fellows are presently in the division. The division should explore a more aggressive approach to soliciting NRC postdoctoral researchers or other students with the goal of training more scientists and engineers in time and frequency science and technology, the end goal being to enhance NIST’s role as an educational resource for U.S. industry.

The quality and quantity of laboratory space has been a problem for the division, but this problem is now being addressed. The Optical Frequency Measurements Group is acquiring newly renovated space, and the Ion Storage Group will receive 270 m2 more space. The quality of space is as important as the quantity. The new space allocated to the Ion Storage Group will be temperature-, humidity-, and vibration-controlled. Having better laboratories will certainly enhance the productivity of the division. It is remarkable that staff have achieved what they have in their present laboratory space.

REVIEW OF JILA

This biennial assessment of the activities of JILA,10 an institute administered jointly by the National Institute of Standards and Technology and the University of Colorado (CU), is based on a meeting of the

10  

Formerly the Joint Institute for Laboratory Astrophysics.

Suggested Citation:"5 Physics Laboratory." National Research Council. 2002. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories: Fiscal Year 2002. Washington, DC: The National Academies Press. doi: 10.17226/10510.
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Subpanel for JILA in Boulder, Colorado, on February 14-15, 2002, and on documents provided by JILA. NIST participation in JILA formally occurs through the Quantum Physics Division of the Physics Laboratory. One member of the Time and Frequency Division is also a JILA fellow.

The members of the subpanel were Frances A. Houle, IBM Almaden Research Center, Chair; Dmitry Budker, University of California at Berkeley; Robert L. Byer, Stanford University; A. Welford Castleman, Jr., Pennsylvania State University; Richard J. Colton, Naval Research Laboratory; Mark A. Kasevich, Yale University; Michael D. Morse, University of Utah; Douglas O. Richstone, University of Michigan; and Ian A. Walmsley, Oxford University.

Technical Merit

According to JILA management, JILA’s vision is this: “JILA, through its work at the frontiers of fundamental and measurement science, enables the future by creating knowledge that both advances understanding and improves the quality of life.”11 This new vision, presented in final form to the subpanel after its meeting in February 2002, dovetails very nicely with the overall mission of NIST to develop and promote measurement, standards, and technology to enhance productivity, facilitate trade, and improve the quality of life.

The present emphases of JILA are on advances in precision measurement; low-temperature states of gaseous matter; laser-based metrologies for extremely sensitive, highly resolved, and ultrafast processes; and characterization of chemical processes. These focus areas are in excellent alignment with the broader mission of NIST. The research activities pursued at JILA actively promote the U.S. economy and the nation’s quality of life by providing essential measurement capabilities and reference data developed by some of the most productive and capable scientists in the world. These contributions provide the scientific basis for optical and nanoscale technologies that are becoming increasingly important for the further development of high-technology industries in the United States. Continued support for the outstanding human resources at JILA, for the infrastructure of the institute, and for its partnership with the University of Colorado, will ensure that this world-class research institute retains its ability to provide a critical foundation for future U.S. technology development.

JILA has been incredibly successful in achieving the goals now expressed in the JILA vision and NIST mission statements. Ample evidence indicates that the JILA fellows work at the forefront of science in many areas. The most obvious demonstration of the institute’s achievements comes in the areas of atomic, molecular, and optical physics, where two JILA fellows were awarded the 2001 Nobel Prize in Physics for their work on Bose-Einstein condensation and the physics measurements that followed from the creation of this unique state of matter. However, while this honor is certainly the highest-profile award given to JILA fellows in the past 2 years, it is by no means the only recognition JILA staff have received. Other honors included a Department of Commerce Gold Medal, a MacArthur Fellowship, a Presidential Early Career Award for Scientists and Engineers, the Joseph F. Keithley Award, the Maria Goeppert Mayer Award, the Samuel Wesley Stratton Award, the Franklin Medal, the Federal Laboratory Consortium Technology Transfer Award, and several elections as fellows of various professional organizations (the American Academy of Arts and Sciences, the Optical Society of America, and the American Physical Society).

In general, the subpanel finds that the work of other JILA fellows and research groups is of comparable quality to the work under way in the areas of atomic, molecular, and optical physics.

11  

Personal communication, J. Faller, National Institute of Standards and Technology, to Frances A. Houle, February 2002.

Suggested Citation:"5 Physics Laboratory." National Research Council. 2002. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories: Fiscal Year 2002. Washington, DC: The National Academies Press. doi: 10.17226/10510.
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Indeed, the subpanel emphasizes that the work leading to the Nobel Prize did not occur in a vacuum. Those results simply could not have been accomplished without the cooperative and collaborative atmosphere engendered at JILA, which in large part succeeds because it brings together the most capable and productive scientists that can be found and then lets them pursue their ideas across laboratory or disciplinary boundaries with little hindrance. JILA provides a model of productive interdisciplinary research that both serves the teaching and research communities on the CU campus and meets the needs of NIST.

An important contributor to JILA’s success is the relatively unusual structure of the institute. It is truly a joint program equally reflective of both partners, a national laboratory and a university. At JILA, NIST provides significant resources and strong ties to industry, while CU provides students and a variety of strong interdepartmental collaborations. This year, the subpanel was very pleased to learn that the newest JILA hire had a joint appointment in the CU Department of Molecular, Cellular and Developmental Biology. This outreach to a group beyond JILA’s traditional collaborating departments (Physics, Chemistry, and Astrophysical and Planetary Sciences) is to be commended, and the relationship appears to be blossoming, with plans both at JILA and in the Physics Department to increase the biophysics expertise at CU. New modeling activities and potential collaborators for the JILA biophysicist in the Applied Mathematics Department also are positive steps for strengthening and expanding JILA’s interactions with CU faculty in a wide variety of fields.

Currently, the activities of the JILA fellows fall into five loosely defined categories: fundamental and precision measurements, optical and nonlinear optical physics, materials interactions and characterization, atomic and molecular interactions and chemical physics, and astrophysics. The subpanel finds that all of these programs continue to produce work of a very high degree of technical merit. In addition to these established programs, JILA is also moving into the area of precision measurements on biophysical systems. This expansion represents a significant extension of the core competencies of JILA into one of the most important developing areas of science.

Highlights

The effective appointment and professional development of young JILA fellows is at the heart of the achievements highlighted below and of other recent JILA accomplishments. At the subpanel’s last review of JILA in 2000, many of the recently hired fellows were just settling in to their laboratories and had not established their reputations within the relevant scientific communities. Now, 2 years later, they are well known and well respected by their peers. The identification of promising young fellows, the appointment of fellows to JILA, and the investment of time and energy in the professional success of each fellow lay the foundation for JILA’s success, and current JILA fellows and management have embraced this process and have demonstrated a deep commitment over time to this goal. The consequence of this focus on appointment and career development is an institute that has young, enthusiastic staff and is capable of identifying and exploring new directions and new ideas. Enthusiasm for new avenues of inquiry pervades JILA, and this culture helps attract the best visiting fellows, postdoctoral scholars, graduate students, and staff. JILA is an exceptional place at the very top ranks of the world’s institutions of science and precision measurement technologies. Below are a few examples of recent achievements that demonstrate how JILA has opened new fields of inquiry and why JILA fellows will continue to do so in the future.

JILA investigators continue to lead the world in the exploration and exploitation of Bose-Einstein condensates (BEC) and Fermi degenerate quantum gases. This work has been recognized with numerous national and international awards, including the 2001 Nobel Prize in Physics. Significant achieve-

Suggested Citation:"5 Physics Laboratory." National Research Council. 2002. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories: Fiscal Year 2002. Washington, DC: The National Academies Press. doi: 10.17226/10510.
×

ments since the subpanel’s last review include manipulation of a Bose gas via tunable interactions, pioneering studies of vortex systems, and record levels of degeneracy in Fermi systems. A stunning recent result is the observation of coherent oscillation between molecular and atomic condensates. In addition to these advances in fundamental science, JILA personnel are also pursuing potential technology applications through a JILA-led DOD Multidisciplinary Research Program of the University Research Initiative, geared toward the development of a new class of rotation and acceleration sensors based on guided-atom techniques.

Two JILA fellows have been at the forefront of developing several important applications for optical combs. Remarkable advances have accrued since the subpanel’s last review. Accomplishments include the combining of two phase-stable mode-locked lasers to produce pulses that are shorter than those of each of the individual lasers, reduction in timing jitter between two lasers to better than 1 fs, the controlled synthesis of pulse trains with widely separated frequencies, and the application of stabilized pulse trains to atomic and molecular spectroscopy. Perhaps the research result with the most impact to date is the demonstration of an “optical clock,” a clock based on an optical frequency standard. This clock provides a tool through which the standards in two very different domains—the optical and the radio-frequency areas—can be brought together. This merger will have important and positive consequences for anyone wishing to use calibrated excitation and measurements with better than 10−15 precision. A measure of the significant difference this work has already made is the increasingly commonplace presence of optical combs in metrology and time-standards laboratories throughout the world as the combs replace the cumbersome frequency chains used over the past decade. The comb technology is approaching the point at which it will be at the center of defining clock standards; this will be a truly revolutionary transition to have occurred in so short a time.

The precision measurement expertise at JILA is also being used to extend measurement technologies to the nanoscale regime and to the level of single-molecule detection. Using an apertureless near-field scanning optical microscopy technique based on an atomic force microscopy, JILA staff can now probe dimensions down to the 2- to 3-nm-length scale. This method is being used to measure the fluorescence of semiconductor CdSe quantum dots and thereby study their excitation and decay. The study of “blinking” of individual quantum dots provides detailed information about the electron-hole pair formation and recombination in quantum dot structures. The ability to measure these phenomena with a precision of 2 to 3 nm could impact future generations of semiconductor devices.

Technical Merit by Program

Fundamental and Precision Measurements. Recently, JILA has built a strong program in optical frequency synthesis. Two years ago, it became apparent that the combination of nonlinear self-phase modulation in glass fibers with very stable mode-locked laser sources could produce a comb of optical frequencies that extended beyond an octave in frequency range. The important characteristic of this technique was that the nonlinear interaction was adequate to produce a broadband “white light” comb of modes but not so nonlinear that it also added phase noise to the comb of frequencies. Therefore, it was possible for the red end of the frequency comb to be frequency-doubled and phase-locked to the blue end of the comb. Further, with additional control, the comb of modes from one laser could be phase-locked to that of a second laser, thus allowing the extension of the frequency comb over an even greater frequency interval. In addition, one frequency of the comb can be phase-locked to an optical frequency standard, thus stabilizing the entire comb of frequencies. This work, led by a recently appointed JILA fellow, has allowed JILA to become the leader in optical frequency synthesis and optical frequency stabilization. The frequency stability achieved at JILA already rivals that of the best microwave

Suggested Citation:"5 Physics Laboratory." National Research Council. 2002. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories: Fiscal Year 2002. Washington, DC: The National Academies Press. doi: 10.17226/10510.
×

frequency standard, and the projected frequency stability is expected to reach a full 2 orders of magnitude beyond that available in the microwave region. As a result of JILA work, optical frequency synthesis, optical frequency standards, and optical frequency clocks are now making giant strides toward becoming the best-available time standard.

JILA continues to lead the world in the development of new instruments and techniques for absolute gravimetry, which has important scientific applications in measurements of the gravitational constant, G, and technological applications in characterization of Earth’s gravitational field. This work continues to thrive and has evolved in two significant directions since the subpanel’s last review: the first is development of a compact, low-cost, field-deployable gravimetry instrument, and the second is a new way to measure G. In each case, the work is of high quality and impact. For example, a low-cost, high-accuracy, absolute gravimeter will be of substantial economic benefit to oil and mineral exploration companies, while a new measurement of G contributes to the world community’s effort to resolve the significant discrepancies observed among recent measurements of this constant.

Another ongoing project is the comparison of the primary frequency standards located at NIST Boulder12 and at the German NMI in Braunschweig, Germany. Each of the clocks has an accuracy of 1-2 × 10−15 in fractional frequency, and the two standards were found to agree within 4-5 × 10−15. This is the first time that this type of comparison has been made to this level of accuracy. Nonetheless, NIST personnel are already actively investigating how the accuracy of the comparison might be improved if better transfer techniques could be utilized. This work is important for improving frequency standards because it will enable an independent assessment of the estimation of contributions of systematic offsets to the output of the cesium fountains.

The fundamental and precision measurements area has traditionally been the point of the strongest interactions between JILA and NIST, supported in a large part by long-term personal relationships between JILA and NIST employees. A number of the parties to these interactions are nearing retirement or have retired. However, the subpanel was pleased to see that some of the new JILA fellows have recognized the value of interactions with NIST and are developing connections with NIST staff, particularly in the area of time and frequency standards.

Optical and Nonlinear Optical Physics. At the forefront of an international effort, work at JILA in the coherent control of the high-harmonic interactions that generate soft x-rays is heralding the beginnings of attosecond science. JILA scientists have shown that some control can be exerted over the highly nonlinear interaction of ultra-intense optical pulses with atomic gases in such a way as to optimize the generation of a particular harmonic peak. Moreover, the group has developed new measurement capabilities to understand the mechanism of the enhancement; these techniques may prove to be applicable to other highly nonlinear optical processes. Overall, the groundbreaking ultrafast laser technology developed at JILA will form the basis of a new generation of attosecond light sources. For example, the ultrafast laser source at JILA has already been used to measure surface adsorbate dynamics with unprecedented clarity. Now the short-time dynamics of charge transfer and reorientation in molecules on surfaces can be studied in a spectral region that provides clear evidence of charge state changes, with temporal resolution previously only available in the optical regime. This new coherent light source will have wide impact in several other areas of physics, chemistry, and materials science. Another potentially important application is the facilitation of information transmission at a very high data rate.

12  

Although carried out by the Time and Frequency Division, this work is overseen by a JILA fellow.

Suggested Citation:"5 Physics Laboratory." National Research Council. 2002. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories: Fiscal Year 2002. Washington, DC: The National Academies Press. doi: 10.17226/10510.
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Another innovative project is the work on guiding ultracold atoms (including condensates) along lithographically patterned magnetic guides on chips. JILA was a leader in efforts to guide atoms in the same way that photons are guided down optical fibers, and a notable recent success is the demonstration of a switch for atoms. (A beam of atoms is guided into a “switchyard” and can be directed to one of two different outputs, depending on the magnetic field, applied using a current-carrying wire in close proximity to the beam.) This technique is the first step toward true atomic waveguiding, in which the DeBroglie wavelength of the atoms is comparable to the size of the waveguide structure. The long-term goal of the project is to enable ultraprecise sensing of gravitational gradients, which could have significant implications for remote sensing, geodetics, and navigation. This project is a collaboration between two JILA fellows, and its success illustrates why JILA and the JILA culture are so productive. First, JILA has enabled two physicists with very different backgrounds to come together to work on a common problem. Second, the culture at JILA values and encourages work such as this, which is aimed at turning cutting-edge science into state-of-the-art technology.

Another of the striking successes rising from the support of collaborative and applied research at JILA is a collaboration between a JILA fellow and faculty in the Department of Electrical Engineering. This combined expertise has enabled the development of an optical autotuning filter for detecting electromagnetic signals in the microwave region. Specifically, this technology provides a means to identify and isolate the largest signal in a broadband, broad area, microwave field using the photorefractive effect, by imposing the microwave signal modulation on a laser beam and filtering it via nonlinear optics. The signal recovery achieved with this optical method is as good as or better than the best reported in the literature, illustrating how nonlinear optics can be used to provide a robust and reliable technology.

Materials Interactions and Characterization. Materials-related activities at JILA mainly focus on research driven by basic scientific discovery, although the results of some projects have the potential to be relevant to important communications tools or other modern technologies. Some of the highlights of the research in the materials area are described below.

One project focuses on the formation and dynamics of optical solitons (solitary waves found in optical systems) in Kerr-lens mode-locked Ti:sapphire lasers. The spectrum shows theoretically predicted soliton instabilities, or “explosions,” appearing as a sudden, intermittent increase (then decrease) in the temporal length of the soliton. The explosions are sensitive to the intracavity dispersion characteristics of the laser. This work may have applications in telecommunications, where use of dispersion-managed solitons is a candidate for a future long-distance communication method.

Another project is studying coherent responses in semiconductors. Although there has been intense work in the community over the past decade on applying ultrafast time-resolved spectroscopic methods to semiconductors, JILA scientists have recently made significant progress on identifying new coherent interactions that had eluded previous efforts. The unrecognized contributions of excitation-induced shifts of the band-edge during excitation show up in nonlinear transient polarizations that can be measured via four-wave mixing. In recent experiments, the transient four-wave mixing signal shows a split peak that can only be explained by many-body interactions among optically excited electrons and holes. These effects are usually ignored in phenomenological models of the interactions, but they may be important in understanding the operation of high-speed laser diodes and light-emitting diodes.

A third project has demonstrated that it is possible to produce a fast, multiple input AND gate using molecular wave packets. First, shaped femtosecond laser pulses have been used to create a coherent superposition of rovibrational molecular states in a gaseous sample of Li2. The resulting quantum wave packet functions as a fast, multiple-input AND gate, with six input values which shape the femtosecond

Suggested Citation:"5 Physics Laboratory." National Research Council. 2002. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories: Fiscal Year 2002. Washington, DC: The National Academies Press. doi: 10.17226/10510.
×

pulse and with the output being read out after a short time delay by a photoionization detection scheme. In this proof-of-principle study, the evolution of the quantum wave packet performs the computation, and the result is readily generalizable to hundreds of input values, which would control the shaped femtosecond pulse.

In a fourth project, the growth of InGaN materials is being investigated using an in situ scanning tunneling microscope to probe the formation of InN islands in the growing samples. The formation of islands is critical for uses of these materials as high-efficiency light emitters, and the project aims to determine the growth conditions necessary for achieving InN island formation. Although this project has not yet generated useful results, the instrument required for the study has been built, and the results of the study will clearly be relevant to the optoelectronics industry and to the broad NIST mission.

In addition to the projects described above, a number of other investigations are under way in the materials area. Work on growing a regular nanostructured array of Ge quantum dots on a lithographically patterned silicon lattice is progressing. No inherent limit on the size reduction of the quantum dots is observed; instead, the limit appears to be determined mainly by the size of the etched features. Finally, several experiments are under way on the chemistry and physics of chemical vapor deposition from silicon-containing gases. One uses light scattering to examine the formation of silicon particles, and another uses threshold ionization mass spectrometry to examine the flux of SixHn radicals to surfaces. An understanding of these processes is important to manufacturers of hydrogenated amorphous silicon photovoltaics and thin-film transistors.

Atomic and Molecular Interactions, Chemical Physics, and Biophysics. Increasing need exists for optical methods to measure the properties of nanoscale objects with sizes below the diffraction limit of light, and JILA researchers have made impressive progress in this area in the past 2 years. The combined effort of two JILA groups resulted in the development of new methods in apertureless near-field scanning optical microscopy (NSOM) that overcome the depth limits constraining other techniques. Resolution improvements down to the 2- to 3-nm-length scale have been demonstrated. Scattering and extinction near-field microscopy have been used to gather impressive data on scattering cross sections that can provide important benchmarks for testing theoretical models of near-field interactions. The findings have enabled evaluation of the scattering cross sections in the presence of an evanescent wave, as a function of distance above the surface. Enormous scattering enhancements for gold nanospheres at less than 5-nm resolution have also been obtained.

In a related significant development, apertureless NSOM has been extended into the domain of near-field fluorescence microscopy, enabling the use of atomic force microscopy (AFM) tips to influence the near-field excitation of dye-doped nanospheres and semiconductor quantum dots down to 6 nm; nearly a thousand-fold enhancement of the near-field laser intensity has been achieved. JILA fellows, in collaboration with a NIST theory group in Gaithersburg, have successfully modeled the strong sensitivity arising from tip elongation, by employing image dipoles generated in the prism when the laser-polarized AFM tip approaches surfaces within one tip radius, including the lightning-rod-antenna effect.

Novel optical microscopy techniques enabled by some of the work described above have allowed other projects to focus on single-molecule spectroscopy. One especially significant result is the discovery and explanation of a “blinking” phenomenon found in the fluorescence behavior of ZnS overcoated CdSe and InP quantum dots on surfaces. Kinetic information about electron-hole pair ejection and recombination demonstrates that there is a wide range of time scales (varying over 5 to 6 orders of magnitude), so the process for these single quantum dot structures must be distinctly nonexponential. In other studies, confocal microscopy methods are being employed to image biomolecules, with the goal of

Suggested Citation:"5 Physics Laboratory." National Research Council. 2002. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories: Fiscal Year 2002. Washington, DC: The National Academies Press. doi: 10.17226/10510.
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studying the intercalation kinetics of DNA tethered to surfaces. A fluorescence technique for time-resolved imaging of single biomolecules in gel electrophoresis is being developed in order to investigate the kinetics of conformational changes in real time.

In a related area, a new JILA scientist was hired by NIST to create a program in biophysical measurement. This exciting new program merges optical-based measurement science, a strength of JILA, with single-molecule studies of fundamental biological processes. The current focus of the program is on measuring the motility of single biological molecules, for example, the movement of enzymes such as RNA polymerase along double-stranded DNA or the repair by recDNA of damaged DNA.

Seven years after their initial observation of BEC, JILA researchers continue to lead the world in the study of ultracold, dilute atomic gases. The exceptionally creative and important ideas being developed at JILA have vitalized and catalyzed research in this area throughout the international scientific community.

Experimental and theoretical work over the past 2 years has focused on the study of interacting Bose and Fermi systems with tunable mean-field interactions, vortex dynamics and vortex lattices, mechanisms for efficient production of degenerate Fermi gases, spectroscopy in very high density samples, techniques for efficient and cost-effective production of these ensembles, and techniques to guide and manipulate ultracold atoms. Each of these studies is of very high scientific and technical caliber. Theoretical work in this area continues at the highest level and includes studies of molecular condensate formation and fermion pairing, as well as ultracold atom collisions. This work will have impact on fundamental science and on technological applications. Scientifically, the study of these systems challenges existing theoretical paradigms, paradigms that are at the forefront of AMO and condensed matter physics. Technologically, BEC and degenerate Fermi systems may enable new generations of ultrasensitive force sensors and time standards. From a broader perspective, the current revolution in nanoscience and quantum information science hinges on understanding the interface between quantum and classical systems. Study of macroscopic quantum BEC and degenerate Fermi samples provides a unique and fruitful path to further knowledge in this area.

In a study with astrophysical implications, a JILA fellow has developed a new theoretical method of calculating the rate of dissociative recombination of H3+ ions struck by low-energy electrons. The distinguishing feature of the calculation is the recognition of the role of Jahn-Teller coupling in the recombination process. This phenomenon has been almost universally ignored in previous theoretical attempts, but it is of critical importance in the proper treatment of the dissociative recombination phenomenon in high-symmetry ions such as H3+. The Jahn-Teller interaction also figured prominently in ultrafast measurements performed by another research group on the vibrational dynamics of Ag3 formed in a nonequilibrium linear geometry by photodetachment of an electron from Ag3. The subsequent bending into the near-equilateral configuration, followed by vibrational randomization within the triple-minimum Jahn-Teller potential energy surface, could be clearly followed with 100-fs time resolution in this experiment. Ultrafast cluster dynamics have also been probed by photodetachment of an electron from the OH-(N2O)m system, leading to the formation of the potentially reactive OH-(N2O) system. The aim of these studies is to learn to prepare bimolecular reaction precursors at well-defined initial conditions for subsequent investigation by ultrafast pump-probe spectroscopy. This approach can yield valuable new information about chemical reaction dynamics in such systems.

In a study of two-electron ejection from a helium atom subjected to an intense pulsed laser field, another group has been able to determine that the dominant mechanism of two-electron ejection is a “recollision mechanism.” Here, the intense laser field accelerates the ejected electron so that it collides with the helium ion again, causing a second electron to be ejected. This is related to processes that are used to generate high harmonics of pulsed laser radiation, and an improved understanding of these processes is likely to result from this work.

Suggested Citation:"5 Physics Laboratory." National Research Council. 2002. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories: Fiscal Year 2002. Washington, DC: The National Academies Press. doi: 10.17226/10510.
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Another JILA group has succeeded in employing a high-order harmonic of a femtosecond pulsed Ti:sapphire laser to generate photoelectron spectra as a function of the time following preparation of the system by a pump laser pulse. This is a major breakthrough, allowing ultrafast probes of chemical dynamics in the gas phase or on surfaces, using the well-understood method of soft x-ray photoelectron spectroscopy. Another important ultrafast investigation has produced a method to implement an evolutionary algorithm to vary the frequency-dependent phases that are contained in a femtosecond pump pulse, so that a particular molecular outcome is optimized. These results will be important for future work employing molecular wave packets to develop quantum-computing algorithms.

Another project uses high-resolution infrared (IR) laser spectroscopy to detect and investigate the reactivity of free radicals, such as those that play an important role in chemical processes of atmospheric or industrial significance. A unique combination of methods involving plasma discharge methods of formation, long-path-length laser absorption methods, and slit supersonic jets is producing spectroscopic data of unprecedented detail. The findings are especially valuable for laser remote sensing of these species. Some attention is also being given to systems where the Born-Oppenheimer approximation is invalid. Similar state-of-the-art techniques are being employed to investigate the state-to-state dynamics for several systems, with emphasis currently on hydrogen abstraction reactions. The result is data that will illuminate crucial details governing the reaction dynamics of atom-diatom systems; this approach has yielded full quantum specifications of the products at far higher resolution than acquired in crossed-beam time-of-flight methods. Direct IR laser absorption techniques developed as part of this work are being used to investigate quantum-state resolved dynamics of reactions at gas-liquid interfaces. The focus is on heterogeneous reactions that may be important in the atmosphere as well as those operative in internal combustion processes.

Astrophysics. The vibrant Astrophysics Program continues to produce excellent results. Its high output of publications, almost entirely in refereed journals, is an indication of the quality of this group, and its work continues to serve the scientific communities and granting agencies that are their primary customers. Some of the highlights of the results from the past 2 years follow.

One project is a study of the various modes of accretion onto black holes. JILA fellows have shown that under some circumstances, the accretion flow near the black hole is coupled to magnetic fields that thread the black hole itself. Consequently, most of the energy dissipation in the disk occurs closer to the black hole than expected. This result makes important predictions for future x-ray observatories. In another project, the same hydrodynamical methods have been employed to study the formation of planets in protoplanetary disks. These disks are also studied spectroscopically at JILA, using data obtained with the Hubble Space Telescope and other satellites. This spectroscopic work provides information on the chemistry occurring within the disks and is relevant to other JILA activities. Another project using hydrodynamical simulation is the work on Supernova 1987a. A JILA fellow’s prediction that the supernova ejecta would run into a surrounding ring of gas is now being confirmed by experimental data, and the next phase of his work focuses on studying the developing interaction between the ejecta and the ring by interpreting data from NASA satellites.

Fluid dynamical simulations are also being used to study the sun. Helioseismology (the study of low-amplitude solar oscillations in millions of normal modes) permits measurements of many physical parameters (such as temperature and rotation speed) deep within the sun; it has allowed scientists to discover that, contrary to theoretical expectations, the sun does not rotate with velocity constant on cylinders. The data instead seem more consistent with rotational velocity constant along radial rays at large distances from the center. Simulations at JILA are being used to test the theory that this behavior is a consequence of turbulence in this region in the sun.

Suggested Citation:"5 Physics Laboratory." National Research Council. 2002. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories: Fiscal Year 2002. Washington, DC: The National Academies Press. doi: 10.17226/10510.
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Other projects include a comparison between the calculations of the spectrum of anisotropies in the cosmic microwave background and the observations of the background. The goal is to find the best-possible estimates of the fundamental parameters of the universe—the mass and energy densities, the curvature of space, the baryon density, and the expansion rate. The project on formation of pregalactic magnetic fields in the youthful universe with no seed fields is focused on understanding the generation of the first magnetic fields, which has been a theoretical challenge for some time.

In the 2000 assessment report, the subpanel noted that JILA’s efforts in gravitational wave research (with connections to the international Laser Interferometer Space Antenna [LISA] program) represented an important synergy between the technology of precision measurement and metrology and the activity in theoretical astrophysics. Unfortunately, one key departure and a critical retirement have greatly reduced the level of activity in this area. In the United States, the center of the LISA program has shifted from JILA scientists (who initiated the project) to NASA centers. Nonetheless, one emeritus JILA fellow is still on the LISA team and remains a spark plug for this project.

The Role of Astrophysics at JILA. As JILA works on defining its vision and planning for its future, one key issue will continue to be the place of astrophysics at JILA, as has been discussed in past reports. The original mission for JILA focused strongly on laboratory astrophysics but has evolved a great deal since then. When NIST formally withdrew from supporting astrophysical research in the mid-1990s, the NIST section of JILA focused on developing a world-class center of excellence in atomic, molecular, optical, and chemical physics. In the late 1990s, the decision was made that the astrophysics fellows still at JILA, on the CU side, would leave JILA and take up residence in the CU Department of Astrophysical and Planetary Sciences, where they all already had faculty appointments. However, since that time, it has become evident that a lack of space on campus will preclude such a move. Therefore, it appears at this time that JILA expects astrophysics to remain as a significant element of JILA and expects the JILA astrophysics fellows to continue to play an active role in JILA management. This shift is evident in the broader vision for JILA that includes the astrophysics community as well as ongoing chemical and physics research and in the discussion of whether an experimental astrophysicist might be hired to take advantage of potential synergies between precision laser measurement expertise and applications of this technology for future space missions.

Currently, there are eight JILA fellows with joint appointments in the CU Department of Astrophysical and Planetary Sciences. All are theoretical astrophysicists. Significant research collaborations between the astrophysicists and the other JILA fellows were not evident at this time, but both groups do appear to value the casual intellectual interactions that occur due to their collocation. Hiring an experimental astrophysicist with interests in the development of cutting-edge astronomical detector technologies could certainly help strengthen the overall relationship of these two groups. Areas of possible synergy would include transition-edge superconducting devices, interferometry and high-precision metrology, gravitational wave physics and precision gravity, and submillimeter detector development. The subpanel acknowledges that finding the right person for this position, someone who is simultaneously an excellent scientist and a superb technologist, would be difficult, but the rewards would be better bridges between the JILA atomic, molecular, and optical sciences group and the JILA astrophysicists and between JILA and the CU Astrophysical and Planetary Sciences Department as a whole.

Program Relevance and Effectiveness

JILA is a vibrant interdisciplinary research institute of the highest caliber. The results and products of JILA’s programs serve a number of potential customers, including researchers in academia, industry,

Suggested Citation:"5 Physics Laboratory." National Research Council. 2002. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories: Fiscal Year 2002. Washington, DC: The National Academies Press. doi: 10.17226/10510.
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and government, and the public. Appropriately, JILA’s primary focus is on scientific and technical communities. The JILA fellows communicate information about ongoing and completed projects to this audience in a variety of ways, including presentations, invited talks, public talks, and publications. These outputs have served researchers well, and JILA clearly continues to be dedicated to these forms of dissemination. During 2000 and 2001, the number of technical papers increased from the previous review period to 340 publications (up by 56 percent), the number of invited talks doubled to 360, and the number of guest researchers rose from 50 to 56. However, apparently because of budget considerations, the number of visiting fellows at JILA will be significantly reduced for the 2002-2003 season. The visiting fellows program brings distinguished scientists to JILA for longer periods of time (4 to 12 months) than might otherwise be possible; these scientists bring new expertise to JILA, and their visits often lead to fruitful, long-term collaborative relationships. This program is a key component of the intellectual vitality of the institute and is an integral part of its ability to serve the scientific community. The subpanel believes that ways to reinvigorate this valuable program should be explored.

JILA interactions with industry do not seem to be as productive as its relationships with the academic community, and these industrial interactions do not appear to be a high priority for JILA. There were no distinguished visitors from industry during the last two review periods (i.e., since 1998). In the mid-1990s, JILA did have a small but growing industrial outreach program managed by one of the JILA fellows, but this activity has all but disappeared. Currently, the one relevant formal activity is the National Science Foundation (NSF)-funded Integrative Graduate Education, Research, and Training (IGERT) Optical Science and Engineering Program (OSEP) at the University of Colorado. This program funds graduate students working in optics and includes a summer internship in an optics-intensive U.S. company. Several students at JILA participate in this program.

Many of the areas of research under way at JILA are particularly interesting to industry, such as the work on time and frequency standards, on advances in ultrafast lasers, and on phase control of ultrafast lasers for precision measurements. JILA fellows, staff, and students would definitely benefit from ongoing interactions with companies that share their interest in the research and technologies central to JILA programs. Also, support for the U.S. economy, in which high-technology industries play a key role, is a key element of the NIST mission. The subpanel learned in conversations with individual fellows that informal interactions do occur between fellows and researchers from both small and large companies, and the subpanel applauds these interactions. However, there was no sign that any formal program was in place to support or encourage these activities, nor was there any indication that these impromptu exchanges of information with individuals from industry were being tracked so that company people might be contacted again for follow-up or for input about or dissemination of future projects of potential interest to these individuals or to others at their companies.

In addition to increasing awareness and tracking of industrial interactions, JILA should also consider establishing a corporate affiliates program to facilitate interaction with companies. The benefits of such a program would include improved visibility of JILA within the broad industrial community, insight into a new set of problems and research areas, expanded employment opportunities for graduating students, and potential increased support for JILA research programs.13 A final element of increased management attention to the issues surrounding industrial interactions should be the careful consideration of a formalized set of policies to guide effective and appropriate technology transfer. JILA currently lacks guidelines in this area, and hence the technology transfer that is occurring takes place on

13  

Over the longer term, affiliates programs in similar laboratories have produced relationships that provided up to 10 percent of the total support for the laboratory.

Suggested Citation:"5 Physics Laboratory." National Research Council. 2002. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories: Fiscal Year 2002. Washington, DC: The National Academies Press. doi: 10.17226/10510.
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an ad hoc basis by individuals adopting what they perceive to be a proper approach. While acknowledging that different relationships will have differing degrees of formality, the range of possible approaches should be clearly spelled out so that JILA scientists are not at risk when faced with the complex options in the technology-transfer arena. JILA should work with both NIST and the University of Colorado to develop a more formal process for technology transfer, both to assist with meeting the public good of transferring technology to the industry and to assist its own fellows, scientists, postdoctoral scholars, and students in understanding and managing the potential conflict-of-interest issues.

For people outside the academic and industrial science and technology communities, JILA also has activities designed to reach a more general audience. All JILA fellows teach CU classes, and one astrophysics fellow is developing interactive Web-based teaching tools, now being adopted by others in the group, that are among the most innovative and exciting in the country. JILA fellows participate in the CU Wizards program, which provides monthly public presentations by CU professors to elementary school students on various topics in science. JILA personnel also interact with local museums; one fellow has been actively involved in the development of interactive exhibits (including a black hole flight simulator) with the Denver Museum of Nature and Science. Recently, existing public outreach efforts have been augmented by the many requests for the two Nobel laureates to give scientific and public lectures about their work.

Finally, a distinctive example of the broad dissemination and wide impact of work done at JILA and NIST is the important and increasingly visible program in time standard distribution. This activity is currently maintained by a JILA fellow from the NIST Time and Frequency Division, which operates an Internet time service that responds to requests for time in a number of standard computerized formats. As of January 2002, these servers were receiving roughly 350 million requests per day, and the demand was growing at a compounded rate of 8.5 percent per month. The success of this service, utilized worldwide, rests on the technology for accurate dissemination of time developed at NIST over many years. For example, the JILA fellow has recently received patents for techniques for dissemination of authenticated time stamps.

JILA Resources

Funding sources for the NIST Quantum Physics Division are shown in Table 5.7.

In the 2000-2001 academic year, NIST contributed roughly $6.5 million to JILA; the University of Colorado contributed roughly $5.5 million to JILA; and outside contracts, grants, and visitor contributions provided roughly $11.7 million (of which about $6.6 million was from NSF). This brought the total 2000-2001 funding for JILA to approximately $23.7 million.

Staffing for the NIST Quantum Physics Division currently includes 12 full-time permanent positions, of which 10 are for technical professionals. There are also 7 nonpermanent and supplemental personnel, such as postdoctoral fellows and part-time workers. Among the University of Colorado staff, there are 16 JILA fellows.

JILA counts 10 Quantum Physics Division researchers and 1 Time and Frequency Division researcher among its fellows and fellow-track members, with expertise in chemistry (2), physics (8), and biology (1). On the CU side, the 18 fellows and fellow-track members are on the faculty of the CU Chemistry (2), Physics (7), and Astrophysics (9) Departments.

It is hard to think of another institution in the world today besides JILA that carries out such truly important work and accomplishes so much with the limited resources available to it. As previous subpanels have pointed out, JILA’s success is attributable to several key elements: the partnership between CU and NIST, the synergy and talents of the researchers, adequate and flexible funding,

Suggested Citation:"5 Physics Laboratory." National Research Council. 2002. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories: Fiscal Year 2002. Washington, DC: The National Academies Press. doi: 10.17226/10510.
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TABLE 5.7 Sources of Funding for the NIST Quantum Physics Division (in millions of dollars), FY 1999 to FY 2002

Source of Funding

Fiscal Year 1999 (actual)

Fiscal Year 2000 (actual)

Fiscal Year 2001 (actual)

Fiscal Year 2002 (estimated)

NIST-STRS, excluding Competence

3.6

3.8

3.9

5.2

Competence

0.3

0.5

0.9

0.4

ATP

0.2

0.2

0.2

0.6

OA/NFG/CRADA

0.6

0.7

0.5

0.3

Other Reimbursable

1.1

1.3

1.3

1.3

Total

5.8

6.5

6.8

7.8

Full-time permanent staff (total)a

11

11

11

12

NOTE: Sources of funding are as described in the note accompanying Table 5.1.

aThe number of full-time permanent staff is as of January of that fiscal year.

excellent technical support, inspired management, a stable and very effective staff, and the physical proximity of its researchers. It is clear to the subpanel that JILA’s leadership has focused considerable effort on the management of these elements of success, in recognition that decline in any of them could seriously weaken the institute. Although largely fruitful, these efforts have met with significant challenges in the past several years, and especially so since the last subpanel review in 2000. These are discussed in the remainder of the report. Left unsolved, these challenges could seriously impair JILA’s ability to do leading-edge science and to recruit and retain talented researchers and will significantly impact the return on NIST’s investments in JILA.

Personnel

Fellows. Six new fellows have been hired over the past 3 years, and JILA’s ability to attract, hire, and mentor outstanding young scientists is a testament to the exciting and supportive atmosphere that pervades the JILA culture. The subpanel was greatly impressed by the superb scientific programs that each of these fellows is developing and commends the management for continuing to provide a unique and nurturing environment in which these young scientists can excel.

However, the success of JILA and its high visibility in the scientific community has a downside: the risk that key individuals may be the targets of recruitment by other institutions. The fellows clearly believe that JILA is a wonderful environment in which to work, but resource and infrastructure limitations certainly do exist; as in all government laboratories, salaries and funding can be an issue. While JILA appears to be able to provide competitive salaries at the early stages of careers, it is possible that the more prominent senior fellows from NIST could receive higher compensation in academia, and other institutions may be willing to offer superior salaries, start-up packages, and infrastructure. On the other hand, NIST’s flexibility in its ability to allocate internal resources to particular areas can work to its advantage, as supplemental research funds can be an important component of a retention package. In addition, the spirit of collaboration and synergistic activity that pervades JILA and the excellence of its

Suggested Citation:"5 Physics Laboratory." National Research Council. 2002. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories: Fiscal Year 2002. Washington, DC: The National Academies Press. doi: 10.17226/10510.
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shops and support people make the institute a very attractive work situation and in general have enabled the retention of sought-after fellows.

For the first time in many years, a NIST-employed JILA fellow is leaving JILA for another institution. Some turnover at JILA is not by definition a negative event. While the departure of this fellow and his large group working in the area of physical chemistry will definitely be a loss, it is also an opportunity for technical evolution of the JILA programs and a chance to consider new directions. As noted above, JILA has clearly demonstrated the ability to hire and nurture outstanding young scientists, and the subpanel is confident that JILA will continue to be able to attract exciting new researchers to the institution. However, transitions are always difficult, and the period following the departure of this fellow in the summer of 2002 will be a very complicated time owing to a number of factors, related in part to the relationship between JILA and the CU Chemistry Department.

The most important decision facing JILA will be what scientific fields to recruit in during the next few years. This issue is not a new one and has been raised in past subpanel assessment reports. The subpanel continues to note that a clear vision for the future of JILA would help guide these decisions. Such choices also must be made in the context of the expertise and programs of the current fellows, and that context will change significantly with the departure of the large group that represents roughly half of the current physical chemistry efforts at JILA. Where JILA will go from here is not clear, and the subpanel feels most strongly that strategic decisions must be made on the basis of how best to maintain JILA’s extraordinary ability to produce cutting-edge work in science and technology and support the NIST mission. At this juncture, it is important and healthy for JILA to consider the centrality of the physical chemistry effort to the institute’s mission. Should the released resources—especially space— be used to develop other research areas such as biophysics or instrumental astrophysics? What would be the long-range consequences of a reduced level of physical chemistry activities in JILA? Several current technical programs, such as the Bose-Einstein condensate work, incorporate physical chemistry expertise and techniques into their projects; would the loss of this discipline within the institute compromise JILA’s ability to move into new frontier areas in the future?

Determining the answers to questions such as these is a complicated process. The subpanel was deeply concerned to learn that this process may be subverted by factors that are inappropriately limiting JILA’s ability to consider recruiting in all appropriate technical areas. While each fellow at JILA is officially associated with either CU or NIST, all have an appointment in a CU academic department. The NIST fellows are usually adjunct professors, but they teach and train CU students at JILA just as the CU fellows do. Therefore, JILA hiring decisions are not made entirely on the basis of JILA’s needs, but in the context of the needs of various departments. This system can be very productive, as seen in the recent hiring of a biophysicist at JILA who will bring to campus new expertise of interest to the Physics Department; the Molecular, Cellular, and Development Biology Department; and possibly the Applied Mathematics Department. However, the system depends heavily on collegial relationships between JILA and the non-JILA faculty in the departments. In the physical chemistry area of the Chemistry Department, the relationships are not cordial, and there is concern at JILA and on the subpanel that this tension may make it impossible to find a mutually acceptable physical chemist to hire.14

JILA will not be without physical chemistry immediately upon the departure of the fellow in 2002, but the anticipated retirement of another physical chemist in the next year or two will reduce JILA to one

14  

Hiring a JILA fellow who is not associated with a CU department is not an option, as the new fellow would be severely hindered in her or his efforts to build a research group involving graduate students as well as postdoctoral scholars.

Suggested Citation:"5 Physics Laboratory." National Research Council. 2002. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories: Fiscal Year 2002. Washington, DC: The National Academies Press. doi: 10.17226/10510.
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experimental physical chemist. One is not a community, and there is a real risk that physical chemistry at JILA may disappear altogether. This would be acceptable only if JILA had decided that such a shift in its focus was appropriate and necessary and had planned a smooth transition and alternative approaches to providing JILA fellows with access to needed physical chemistry expertise. If, however, the relationship with the Chemistry Department forces JILA into a decision that is not based on a careful assessment of the centrality of physical chemistry to JILA’s mission, that will be a very unacceptable outcome.

JILA management, the JILA fellows, NIST, and CU are facing a very challenging set of circumstances, and the subpanel urges all concerned to work toward resolution of the situation. In the past, the subpanel has suggested that JILA consider establishing a committee to liaise with university departments, but it is clear that a more formal and extensive effort will be needed. Both NIST and CU benefit greatly from the success of JILA, and JILA’s health as an institution depends heavily on the identification of common interests with CU’s academic departments. Therefore, the subpanel recommends that NIST and CU work together to ensure coordination and healthy collaborations with relevant CU departments, including Chemistry; Physics; Astrophysical and Planetary Sciences; and possibly the Molecular, Cellular, and Development Biology Department and the Applied Mathematics Department. One possible approach would be for NIST and CU to jointly establish a committee charged with examining the current status of the working relations between JILA and the relevant CU departments. The committee would report findings and recommendations to both NIST and CU.

Even if the situation with the Chemistry Department is resolved, the transitions of the next few years still have the potential to make this time an unsettled period at JILA. The loss of a prominent colleague after a serious retention effort is demoralizing. The vacancies associated with the retirement of a number of senior fellows over the next 5 or so years also have the potential to create tension at an institution run to a remarkable degree by consensus processes. Special care must be taken to assure that a departure does not stimulate additional departures that could lead to the collapse of the extraordinary and productive environment now at JILA.

Management. JILA’s management structure and governance structure with a rotating chair of JILA and a permanent chief of the NIST Quantum Physics Division appears to work well. The absence of a formal mechanism for long-range planning seems unusual, but it appears to be mitigated by a shared sense of vision among some of the senior fellows. While the institute makes sensible and even inspired decisions about its future within its present structure, a more formalized planning mechanism could improve JILA’s ability to respond to difficult situations (such as the hiring decisions to be made in the wake of this year’s departure of a fellow and issues related to facilities problems and improvements). The management of the NIST Quantum Physics Division, which is a subset of JILA, has additional responsibilities to ensure support of the NIST mission. The subpanel finds that although a great deal of attention is paid to hiring and resource matters, long-range planning and management of industrial interactions and intellectual property are not addressed at the same level.

Staff, Students, and Postdoctoral Researchers. The subpanel was impressed by the positive morale among staff, students, and postdoctoral researchers at JILA. They all appeared to feel privileged to be associated with the institute and seem to receive significant satisfaction from participating in important and interesting work. The comments below reflect topics that were discussed when the subpanel met separately with each of these groups.

The support staff is highly capable and the electronics and machine shops at JILA are of very high

Suggested Citation:"5 Physics Laboratory." National Research Council. 2002. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories: Fiscal Year 2002. Washington, DC: The National Academies Press. doi: 10.17226/10510.
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caliber; access to these JILA shops, technicians, and support people is a key contributor to JILA’s success. There is a strong esprit de corps among JILA employees, who feel appreciated by the scientific staff. A new program is a series of Tuesday meetings, in which the fellows describe specifically for the staff the technical work they are supporting. These meetings are very valuable and are appreciated by the staff. Continued enhancement of modes of communication will reinforce the atmosphere of mutual respect that pervades the laboratory.

Graduate students also appeared to be very happy at JILA. The only potential concern expressed was the variation in the level of support provided, as stipends and benefits depend on the students’ home department and on whether they are affiliated with OSEP. Finally, the postdoctoral scholars expressed similar levels of pride at being associated with JILA. They were particularly impressed with its infrastructure. The major inconvenience for them related to the policy of making postdoctoral scholar appointments for 1 year at a time, even though these appointments are typically renewed for a total appointment of 2 or 3 years. While the rationale for this approach is certainly sensible, it poses a real burden for foreign scholars, who must return to their home countries to reapply for a visa after the first year. This absence is disruptive to research and expensive for the researcher. The fellows may wish to examine the tenures of their past postdoctoral scholars and consider whether an initial 2-year appointment would be in the best interests of the research groups and of JILA.

Facilities

The previous subpanel review called attention to several challenges posed by JILA’s aging and inadequate physical plant. The shortcomings fall into two categories. First, there is a serious, long-term, crowding problem; the amount of space is insufficient to accommodate the activities of all of the JILA fellows and their groups. Next year, JILA will have a temporary reprieve on this front when a significant part of the physical chemistry activity leaves and a good deal of laboratory space will be freed up. While this newly available space will relieve the crowding in the short term, a long-term solution is still needed. There is funding in the 2005 NIST budget projection for vertical expansion of the present building, and corresponding funding exists in the CU plan. The subpanel did not see detailed plans for this expansion, but the funding levels discussed (a total of about $6 million) do not seem to be consistent with the magnitude of the desired expansion (adding about 50 percent more space). Additionally, the contemplated plan for expansion involves the addition of stories above and below the present building, which will be rather disruptive to the ongoing research activities of the laboratory. If JILA obtains the funding and goes forward with this approach, a plan to mitigate the disturbance associated with the construction will be needed before work starts.

The second class of facilities issues relates to problems associated with the physical condition of the current facility. The building is showing its age, and the environmental control in many of the laboratories is inadequate. While the skills and creativity of JILA scientists and staff are compensating for the dust, inadequate ventilation, and poor thermal control in the JILA laboratories, the subpanel believes that this is a temporary and inefficient solution to the problems. Efforts are being made to find funding for improvements (CU recently agreed to provide $500,000 specifically targeted at improving temperature control), and technological solutions are currently being found at the level of individual rooms. This approach, while better than working in inadequate space, is still not cost-effective. For example, temperature control was improved in one laboratory recently so that single-molecule manipulation could be performed, but the extension of similar capabilities to the other laboratories on a room-by-room basis will require much more than the $500,000 currently available.

Suggested Citation:"5 Physics Laboratory." National Research Council. 2002. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories: Fiscal Year 2002. Washington, DC: The National Academies Press. doi: 10.17226/10510.
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JILA’s Responsiveness

The subpanel found that, on the whole, JILA had been somewhat responsive to the recommendations made in the previous (2000) assessment report. The subpanel was pleased by JILA’s actions in the area of hiring interdisciplinary researchers and on facilities issues but concerned about JILA’s lack of action in developing a vision for the institute, putting together a committee to nurture relationships with CU academic departments, and focusing and tracking its industrial interactions.

With respect to the positive actions—in 2000, the subpanel recommended that, as new fellows with research activities in interdisciplinary areas were hired, JILA should develop new partnerships with relevant CU departments. In 2001, a new fellow with biophysics expertise joined JILA, and through him, ties are being formed to molecular biology and applied mathematics faculty on the CU campus. This is a positive step for both JILA and CU, and in future years the subpanel will assess the evolution of these relationships. In 2000, the subpanel also recommended that NIST and CU find ways to improve the quality and quantity of laboratory space. This is a difficult task because of the large amount of money and time required to make a significant difference in facilities, but the subpanel was pleased to see that JILA, NIST, and CU management are making active and creative efforts to address the problem. Some progress has been made, and the subpanel will continue to monitor the situation. The subpanel was disappointed to learn that there were three recommendations from the 2000 report on which JILA took no action:

  1. To develop a strategic vision for the JILA of the future to guide hiring and resource allocation decisions;

  2. To appoint a committee to strengthen ties to all the CU departments with which JILA is allied; and

  3. To determine what industrial activity at JILA should be, review JILA’s track record with meaningful metrics, and put in place a plan for industrial activities that is appropriate to the JILA-NIST mission.

While the subpanel recognizes that the recommended actions can be difficult tasks, it was concerned that no attempts at these actions appear to have been made and that no reason for JILA’s lack of action in these areas was provided to the subpanel.

The subpanel was particularly uncomfortable with JILA’s lack of action in the first area. The subpanel recognizes that despite the absence of a formal long-range plan, JILA has been able to optimize its course. Nevertheless, strategic thinking has been called for by previous panels and formal strategic planning is currently a focus area within NIST. The 2002 panel was able to obtain a vision statement from JILA management during the assessment, but this is only a beginning: the statement was not reviewed by the JILA fellows, and the strategic ramifications of the statement have not been developed. The lack of progress in the other two areas is also unsettling. Evidence for difficult relations with some CU departments was obvious in 2000, and this has since become a major issue. The casual attitude about coordination of industrial activities is difficult to understand, considering that the NIST mission includes supporting the U.S. economy. Lack of progress in these three areas is unacceptable and should be actively monitored in the reviews by future subpanels.

Major Observations of the Subpanel

The subpanel presents the following major findings and recommendations.

Suggested Citation:"5 Physics Laboratory." National Research Council. 2002. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories: Fiscal Year 2002. Washington, DC: The National Academies Press. doi: 10.17226/10510.
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Findings
  • The JILA programs, supported by CU and by NIST as well as by government contracts, thrive in an environment of interactive research in which synergies between the fellows are exploited across multiple disciplines. JILA’s record of successful identification, appointment, and career development of fellows is a key factor in producing the high-quality research that occurs at JILA.

  • JILA is an extraordinary, vibrant institution, thanks to a confluence of several key elements of success, including the partnership between CU and NIST, the synergy between and physical proximity of the researchers, excellent technical support, and adequate and flexible funding. However, some issues, such as resource and infrastructure limitations that may affect retention, pose a challenge to the preservation of all of the elements that contribute to JILA’s success. A formal vision for JILA, which could guide critical decisions, has not yet been developed.

  • Through creative and exciting research, JILA serves its academic customers with distinction. However, JILA’s service to industry continues to be less organized and less effective than is desirable, and JILA has in fact lost ground in developing its industrial connections since the last assessment in 2000. The transfer of discoveries and inventions to the commercial stream for public benefit is one aspect of the mission and responsibility of JILA, but the lack of guidelines on effective technology transfer places fellows at risk when they are faced with the complexities of conflict-of-interest issues in technology transfer and industrial interactions.

  • The departure of a senior NIST JILA fellow is an opportunity for growth and evolution, and recruitment of new staff will be facilitated by JILA’s current high visibility in the scientific community. However, the strained relationship between JILA and the CU Chemistry Department is constraining JILA’s ability to hire new physical chemists, making it very difficult for JILA to make rational decisions about the future direction of physical chemistry at JILA.

  • The quality of the physical plant at JILA is not commensurate with the quality of the science, and, though some progress has been made, adequate funds are not currently available to fully remedy this situation. The existence of superb shops and staff have enabled the fellows to do world-class work, but spending time and money on “work-arounds” is not cost-effective.

Recommendations
  • NIST and CU should jointly establish a committee to examine the current status of the working relations of JILA with relevant CU departments, including Chemistry; Physics; Astrophysical and Planetary Sciences; and possibly Molecular, Cellular, and Development Biology and Applied Mathematics. The committee should be charged by and report back to both NIST and CU with its findings and recommendations.

  • JILA should establish a formal program to support and encourage industrial interactions and should track these interactions. JILA, working jointly with NIST and CU, also needs to establish and formalize policies for technology transfer and best practices in interactions with companies.

  • The JILA laboratory needs a comprehensive space and renovation plan. NIST and CU should provide the funding needed to implement such a plan.

  • JILA should debate and build on its newly proposed vision in order to develop an overall vision for the future of JILA; this vision should provide a context for critical decisions about hiring and infrastructure improvements that need to be made in the next few years.

Suggested Citation:"5 Physics Laboratory." National Research Council. 2002. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories: Fiscal Year 2002. Washington, DC: The National Academies Press. doi: 10.17226/10510.
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This assessment of the technical quality and relevance of the programs of the Measurement and Standards Laboratories of the National Institute of Standards and Technology is the work of the 165 members of the National Research Council's (NRC's) Board on Assessment of NIST Programs and its panels. These individuals were chosen by the NRC for their technical expertise, their practical experience in running research programs, and their knowledge of industry's needs in basic measurements and standards.

This assessment addresses the following:

  • The technical merit of the laboratory programs relative to the state of the art worldwide;
  • The effectiveness with which the laboratory programs are carried out and the results disseminated to their customers;
  • The relevance of the laboratory programs to the needs of their customers; and
  • The ability of the laboratories' facilities, equipment, and human resources to enable the laboratories to fulfill their mission and meet their customers' needs.
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