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Suggested Citation:"5 Physics Laboratory." National Research Council. 1998. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories, Fiscal Year 1998. Washington, DC: The National Academies Press. doi: 10.17226/9515.
×

Chapter 5

Physics Laboratory

Suggested Citation:"5 Physics Laboratory." National Research Council. 1998. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories, Fiscal Year 1998. Washington, DC: The National Academies Press. doi: 10.17226/9515.
×

PANEL MEMBERS

David H. Auston, Rice University, Chair

Thomas M. Baer, Arcturus Engineering, Inc.

Anthony J. Berejka, Consultant, Huntington, N.Y.

Shirley Chiang, University of California, Davis

Gregory R. Choppin, Florida State University

Stuart B. Crampton, Williams College

Leonard S. Cutler, Hewlett-Packard Company

Paul M. DeLuca, Jr., University of Wisconsin–Madison

Harold Metcalf, State University of New York, Stony Brook

David W. Pratt, University of Pittsburgh

David A. Shirley, Lawrence Berkeley National Laboratory (retired)

Winthrop W. Smith, University of Connecticut

Arthur W. Springsteen, Labsphere, Inc.

Robert G. Wheeler, Yale University

Stephen M. Younger, Los Alamos National Laboratory

Submitted for the panel by its Chair, David H. Auston, this assessment of the fiscal year 1998 activities of the Physics Laboratory is based on site visits to the laboratory by the panel on March 5–6, 1998, and the annual report of the laboratory.

Suggested Citation:"5 Physics Laboratory." National Research Council. 1998. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories, Fiscal Year 1998. Washington, DC: The National Academies Press. doi: 10.17226/9515.
×

LABORATORY-LEVEL REVIEW

Laboratory Mission

The mission of the NIST Physics Laboratory, as stated in its annual report, 1 is to support U.S. industry by providing measurement services and research for electronic, optical, and radiation technologies.

The laboratory's mission, though broad, is consistent with the overall mission of NIST. The laboratory develops, maintains, and disseminates the national standards for optical and ionizing radiation, time and frequency, and radiation temperature. The programs carried out in pursuit of this mission are generally quite appropriate and well targeted.

Technical Merit and Appropriateness of Work

The technical merit of the ongoing programs in the Physics Laboratory is very high, and many of the laboratory's efforts are at or define the state of the art in their field. For example, the upgrade of the laboratory's Synchrotron Ultraviolet Radiation Facility (SURF) will give NIST the premier absolute broadband radiometric source covering the far infrared through the extreme ultraviolet (EUV) regions of the electromagnetic spectrum. The laboratory continues to push the state of the art in mid- and far-infrared molecular spectroscopy for chemical and biological applications. The Time and Frequency Program at NIST is one of the best, if not the best, in the world. And NIST researcher Dr. William Phillips shared the 1997 Nobel Prize in Physics with two other scientists for his work in developing laser cooling and trapping of atoms. Further examples of the laboratory 's work are found in the divisional reviews below.

The laboratory's work in databases merits special mention here. The Physics Laboratory maintains large databases of fundamental atomic and molecular properties, including atomic energy levels, transition probabilities, and emission and absorption wavelengths. These databases are essential to developing and modeling industrial processes and to understanding the earth 's environment and in many other applications. These data compilations are among the publications most often referenced in the technical literature. They are important national resources that have required decades of focused effort to develop.

The panel was very impressed with the laboratory's new Web page of the Fundamental Constants Data Center. This page provides in-depth information on the fundamental physical constants, the International System of Units, and the expression of uncertainty in measurement. The searchable, user-friendly nature of the information related to the constants is especially noteworthy and should make this one of NIST's most visited sites. Because the fundamental constants are at the foundation of all of science and technology, periodically providing the scientific and technical communities with the best values available is of great importance and a critical responsibility of the Physics Laboratory. The panel was thus pleased to see that the laboratory will be completing the new Committee on Data for Science and Technology (CODATA) adjustment of the values of the constants by the end of 1998. This new, up-to-date

1  

U.S. Department of Commerce, Technology Administration, National Institute of Standards and Technology, Physics Laboratory: Annual Report 1997, National Institute of Standards and Technology, Gaithersburg, Md., 1998.

Suggested Citation:"5 Physics Laboratory." National Research Council. 1998. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories, Fiscal Year 1998. Washington, DC: The National Academies Press. doi: 10.17226/9515.
×

set of values is sorely needed because there have been many improvements in experiment and theory in the last decade or so and the 1986 CODATA set, the most recent available, is badly out-of-date. A great deal of computer automation has been incorporated into the new adjustment, allowing CODATA to provide a new set of values at least every 4 years, or as often as every 2 years if new data warrant it. In the panel 's view, the initial overhead costs in time and effort of developing the extensive computer programs that will allow this significantly increased frequency is well worth it; 12 years between adjustments is unacceptable at a time when users rightfully expect new information to be immediately available. The panel was glad to see that such a long interval between updates is not likely to occur again.

This worthy goal of updating the database of fundamental constants every several years will require a continuous effort—it cannot be done unless staff are allowed the time to keep fully up-to-date with the relevant experimental measurements and theoretical calculations reported between adjustments. Even after the 1998 adjustment is completed, resources must be provided so staff members can devote time to keeping current on all relevant new developments, maintain the bibliographic database on the constants, and contribute to the advancement of the field, for example, by developing and maintaining an online database on precise hydrogenic energy levels relevant to determinations of the Rydberg constant.

As mentioned previously, the programs that the laboratory is engaged in are generally quite appropriate. It was not clear to the panel whether program priorities had been chosen based first on industry needs, rather than on laboratory capabilities. When asked, the laboratory produced a list of programs that had responded rapidly to specific industry requests, indicating that the laboratory can and does redirect its efforts toward specific industrial needs when they arise.

Impact of Programs

Although not every program is equally successful, overall the laboratory has an impressive record of impact on specific industrial needs. Details on impact are given in each divisional report below, but a few items are highlighted here as examples.

Downloads from the laboratory's database Web site have been growing exponentially, and the number of pages delivered to customers from the Web site increased from 32,000 to 64,000 per month over the last year. This site includes physical constants, atomic and molecular spectroscopic data, ionization data, x-ray and gamma-ray data, nuclear and condensed matter physics data, and other NIST data. Users of these data span the spectrum from university students to industrial researchers, and the data 's availability provides a major infrastructural support to science and technology in related areas. For example, wavelength measurements of rare-earth metal spectra are used by the lighting industry in designing more energy efficient products with better color balance.

The laboratory provides standards and measurement quality assurances to the lighting, photographic, automotive, xerographic, and electronics industries, among others. State-of-the-art spectroscopic research will provide new and improved standards and calibration services for industry. Through its Council on Ionizing Radiation Measurements and Standards (CIRMS), and Council for Optical Radiation Measurements, the laboratory receives industry input on measurement and standards needs in those areas.

Suggested Citation:"5 Physics Laboratory." National Research Council. 1998. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories, Fiscal Year 1998. Washington, DC: The National Academies Press. doi: 10.17226/9515.
×
Laboratory Resources

Funding sources2 for the Physics Laboratory (in millions of dollars) are as follows:

 

Fiscal Year 1997

Fiscal Year 1998 (estimated)

NIST-STRS, excluding Competence

29.8

31.4

Competence

2.9

1.9

ATP

0.8

1.6

MEP

0.0

0.0

Measurement Services (SRM production)

0.3

0.3

OA/NFG/CRADA

9.6

9.7

Other Reimbursable

3.4

3.4

Total

46.8

48.3

Staffing for the Physics Laboratory currently includes 207 full-time permanent positions, of which 174 are for technical professionals. There are also 56 nonpermanent and supplemental personnel, such as postdoctoral fellows and part-time workers.

The laboratory's programs still suffer from the deterioration in physical plant described in the panel's previous report. For example, rainstorms create leaks in offices and laboratories, and there is seepage in the below-grade vaults used to house accelerators in the Radiation Physics Building. Scientists are forced to spend time and effort on expensive work-arounds to obtain the temperature control, humidity control, vibration control, and cleanliness that are necessary for their high-precision measurements. This diversion of time and resources should not be necessary at a world-class institution like NIST. NIST has developed a Facilities Improvement Plan that, if funded and implemented, would greatly relieve the conditions described.

The panel was pleased to learn that the laboratory has a succession plan in place to ensure its continued international leadership in fundamental constants. Updated values of these present constants are free to users, and this is indeed a most valuable aspect of this service. It enables multiple-student access, encourages browsing, and otherwise provides a valuable asset to the scientific and technical community in government, industry, hospitals, universities, and other

2  

The NIST Measurement and Standards Laboratories funding 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 it is allotted 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. Manufacturing Extension Partnership (MEP) funding reflects support from NIST's MEP for work done at the NIST laboratories in collaboration with or support of MEP activities. Funding to support production of Standard Reference Materials 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.

Suggested Citation:"5 Physics Laboratory." National Research Council. 1998. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories, Fiscal Year 1998. Washington, DC: The National Academies Press. doi: 10.17226/9515.
×

technologically oriented enterprises. Although the imposition of user fees to recover some of the costs of this service might permit some expansion and strengthening of the service, they would have a negative impact on its current broad dissemination, especially to students and young scientists.

DIVISIONAL REVIEWS

Electron and Optical Physics Division
Mission

The Electron and Optical Physics Division's mission is to develop measurement capabilities needed by emerging electronic and optical technologies, particularly those required for submicron fabrication and analysis.

In pursuit of its mission, the division maintains an array of research, measurements, and calibration activities. It provides the central national basis for absolute radiometry in the far ultraviolet and EUV regions of the electromagnetic spectrum, maintains specialized facilities for scanning electron microscopy with polarization analysis and scanning tunneling microscopy (STM), maintains an EUV optics characterization facility, and performs theoretical and experimental research in atomic and condensed matter physics in support of its basic mission objectives.

The division has specific programs to develop techniques for the following purposes: determining magnetic microstructures; establishing the physical and chemical basis of device fabrication on the atomic scale; producing and characterizing artifacts with atomic-scale quality control; maintaining expertise in physical and applied optics in the 10 to 100 nm wavelength range; maintaining the national radiometric standard in the 2 to 250 nm wavelength range; and delivering quality measurement, calibration, and secondary standards services in the 2 to 50 nm wavelength range. These programs clearly conform to the division mission stated above. The division programs also support the Physics Laboratory mission and NIST mission. The division has specific examples of supporting U.S. industry directly, in addition to performing extremely high-quality research that anticipates industrial measurement standards and needs.

The division's mission statement fails to include the division's efforts to provide measurement support for existing technologies. The division could consider correcting this oversight.

Technical Merit and Appropriateness of Work

The division's Photon Physics Group has continued its leadership role in the development of new technology in the EUV and x-ray regions of the electromagnetic spectrum and in the application of this technology to basic and applied research. The group's primary focus has been developing instrumentation to complement the unique capabilities of the SURF II synchrotron light source, which allows application of this source to a variety of problems in metrology. In particular, the group has made substantial progress in developing thin film coating techniques for

Suggested Citation:"5 Physics Laboratory." National Research Council. 1998. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories, Fiscal Year 1998. Washington, DC: The National Academies Press. doi: 10.17226/9515.
×

the EUV and x-ray regions of the spectrum. Their approach utilizes nontraditional thin film materials, for example, molybdenum/silicon, that are necessary to withstand the large photon energies at these short wavelengths. The group has developed a unique thin film coater, combining electron beam deposition of films with ion milling, to achieve ultraprecise levels of surface flatness and surface roughness on optical surfaces. The group has already achieved x-ray reflectivities on its optics that exceed 50 percent at normal incidence. This achievement will allow the construction of a number of important x-ray microscope devices with applications in microelectronics and biotechnology. As a spin-off of this program, the group has measured and published the indices of refraction for the coating materials used in this spectral region (B4C, C, Mo, Si, and W), which is a critical part of developing x-ray optical coating technology.

The group has used their expertise in x-ray optics to help develop tomographic techniques that allow three-dimensional measurements of submicron features in integrated circuits. They have demonstrated spatial resolution down to 100 nm. This research has direct applications in the metrology of submicron structures that are a critical part of next-generation integrated circuits.

The Photon Physics Group has continued its efforts in far UV metrology by successfully concluding a several-year effort to measure the 1S to 2S transition in atomic He using high-precision, Doppler-free, two-photon laser spectroscopy. This result provides a benchmark challenging the accuracy level of current theoretical calculations of quantum electrodynamic effects such as the Lamb shift and the electron-electron correlation correction to the atomic levels in neutral He.

The Far Ultraviolet Physics Group's upgrade of the SURF from SURF II to SURF III is proceeding smoothly. SURF II was closed and dismantled in late 1997. With continued progress on the current schedule, SURF III should be operational in the fall of 1998. The new SURF III facility will provide a world-class, absolute radiometric capability. The magnet pole faces and other critical surfaces are planar to ±0.001 in., permitting very high magnetic field uniformity. The other parameters for assuring accurate absolute radiometric standards measurements are also in place. In addition, the projected higher electron energy will increase the accessible photon energy, allowing the study of organic and biological materials. SURF III will be the world's premier absolute broadband radiometric source in the far infrared through the EUV regions of the electromagnetic spectrum. This is of great value for both science and industry.

The Electron Physics Group is a world leader in high-resolution imaging of magnetic materials, both by STM and scanning electron microscopy with polarization analysis (SEMPA). Staff have developed spectroscopic techniques for elemental identification of iron and chromium metal atoms with atomic resolution in magnetic surface structures. The group has also developed novel fabrication methods for nanowires and nanotrenches by reactive-ion etching of laser-focused chromium. Such chromium lines have also been used as a self-shadowing mask for deposition of nanoscale magnetic wires of iron. In addition, the group has excellent theorists who work with the experimentalists on understanding of giant magnetoresistance (GMR) effects in thin magnetic films. Another recent accomplishment relates the measurement of the magnetic exchange coupling in Fe/Au/Fe(100) sandwich structures using a unique confocal magneto-optical microscope to the atomic scale roughness of the films measured with reflection high-energy electron diffraction.

The new Nanoscale Physics Facility will be state of the art when it is completed at the end of 1998. The facility will be used to elucidate the physics of electron confinement and transport in nanoscale structures and devices, such as two-dimensional electron gases, quantum wires and

Suggested Citation:"5 Physics Laboratory." National Research Council. 1998. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories, Fiscal Year 1998. Washington, DC: The National Academies Press. doi: 10.17226/9515.
×

dots, and magneto-transport devices. This facility is centered on the measurement capability of a cryogenic, ultrahigh vacuum STM that will operate at temperatures as low as 2 K with the ability to apply magnetic fields of varying orientation up to 1.5 T, or a fixed orientation field up to 10 T. The system is also equipped with molecular beam epitaxy fabrication of metal and semiconductor devices, with in-vacuum transfer of fabricated samples among the chambers. Measurements will be performed with both atomic-scale positional resolution and high-resolution of electronic state spectroscopic features.

The group has also been collaborating with the NIST Electronics and Electrical Engineering Laboratory (EEEL) on quantitative comparisons between various magnetic imaging techniques. The EEEL has fabricated a magnetic imaging test sample from thin film high-density magnetic recording media with a test pattern and lithographically patterned navigation marks to allow repeated measurements of the same area of the sample. Quantitative magnetization information from the Electron Physics Group's SEMPA technique will be compared with information about the magnetic contrast observed in magnetic force microscopy images measured by many other groups.

The group's significant efforts in characterization of magnetic thin films and in fabrication of nanowire structures are both extremely important to U.S. industry in magnetic storage technology and next-generation integrated circuit manufacturing. Future research directions on magnetic exchange coupling strengths of antiferromagnets, metastable atom lithography, and the use of laser-focused chromium lines as a nanoscale length standard build on successful work of the group and are completely in accordance with the division, laboratory, and NIST missions.

Impact of Programs

The operation of SURF II has supported the measurement and calibration services and research efforts of the division, as well as other NIST units and external customers. A dedicated reflectometer system on Beam Line-7 at SURF II has been used to determine reflectivities of multilayer optics in the EUV, as well as grating efficiencies and film dosimetry. Over 60 samples from industry, other government laboratories, and universities were analyzed in 1997 (this number is lower than in previous years because of the SURF II shutdown). The spectrometer calibration service on BL-2 supports NASA programs in solar physics and EUV astronomy. BL-9 and a new dual grating monochromator on BL-2 are used for UV and EUV detector transfer standards.

The Electron Physics Group has a notable history of working directly with many different companies on magnetic characterization of samples by SEMPA. The problems analyzed for various companies included the following: noise behavior in hard disk recording media for Seagate Magnetics; domain motion and structure of magnetic recording heads for Digital Equipment Corporation; magnetic configuration of magnetic random access memory cell for Nonvolatile Electronics, which led to the solution of a 2-year-old dynamic switching problem; measuring pinning sites leading to energy losses in amorphous magnet transformer material for AlliedSignal; and planning collaborations on magnetic microstructure problems for the National Storage Industry Consortium.

Suggested Citation:"5 Physics Laboratory." National Research Council. 1998. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories, Fiscal Year 1998. Washington, DC: The National Academies Press. doi: 10.17226/9515.
×
Resources

Funding sources for the Electron and Optical Physics Division (in millions of dollars) are presented below:

 

Fiscal Year 1997

Fiscal Year 1998 (estimated)

NIST-STRS, excluding Competence

4.7

5.0

ATP

0.1

0.2

OA/NFG/CRADA

0.8

0.5

Other Reimbursable

0.1

0.1

Total

5.7

5.8

Staffing for the Electron and Optical Physics Division currently includes 27 full-time permanent positions, of which 24 are for technical professionals. There are also eight nonpermanent and supplemental personnel, such as postdoctoral fellows and part-time workers.

Atomic Physics Division
Mission

The mission of the Atomic Physics Division is to carry out a broad range of experimental and theoretical research in atomic physics in support of emerging technologies, industrial needs, and national science programs.

The division's mission statement fails to include its work in standards and databases for atomic quantities. This is an omission that might merit consideration.

Technical Merit and Appropriateness of Work

The Atomic Physics Division continues to be an international center of excellence in atomic and plasma physics. The core of this division 's work is new measurement methods, spectroscopic standards, and reference data. Its several groups have earned the respect of the entire community, and one of its researchers was awarded the 1997 Nobel Prize in Physics.

The very detailed theoretical work on quantum dots and other microscopic structures in the Quantum Processes Group is promising for both physics and applications. Their theoretical work on ultracold collisions is closely related to the laser cooling and trapping experimental work for which the Nobel Prize was awarded. It is appropriate that a new staff member has just been added to this group.

The Atomic Spectroscopy Group does research in obtaining atomic spectral data in the optical region for neutral and ionized atoms and provides published data compilations of critically evaluated atomic energy level and wavelength data. Two different approaches are used in data

Suggested Citation:"5 Physics Laboratory." National Research Council. 1998. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories, Fiscal Year 1998. Washington, DC: The National Academies Press. doi: 10.17226/9515.
×

compilation: First, measurements or calculations of fundamental atomic data made by researchers worldwide are collected and critically evaluated for accuracy and reliability. Second, the Atomic Spectroscopy Group maintains unique experimental facilities to directly measure fundamental properties. One highlight of the laboratory research of this group is the new Fourier transform (FT) spectrometer that is now operational and that has produced new wavelength measurements of the rare-earth spectra of dysprosium I and dysprosium II. This research is supported by the Electric Power Research Institute, a research consortium serving the lighting industry. Rare earth additives to be used, for example, in stadium lamps, are being investigated for greater efficiency and better color balance. This is significant, since commercial lighting represents about 20 percent of all U.S. electric power consumption. The laboratory is also providing atomic data needed to develop new, mercury-free, fluorescent lighting systems that will be more efficient and reduce mercury pollution from discarded lamps. With the kind of data provided by the Atomic Spectroscopy Group at NIST, modeling can replace increasingly expensive and time-consuming empirical testing. Current efforts are aimed at providing data to help manufacturers model ways to improve lighting efficiency by as much as a factor of two.

The use of these data should increase in the future as large-scale numerical simulation is taken up by more and more industrial and scientific users. At present there are about 10 personal requests for these data per week. In the fall of 1997, the division sponsored a major international conference on atomic and molecular data and their applications with the division chief as the principal organizer.

The Gaseous Electronics Conference plasma reference cell developed by the Plasma Radiation Group uses optical, radio-frequency, and electrical probes to determine and standardize measurement of plasma properties, particularly for industrial uses such as plasma etching of semiconductor wafers. The group recently developed a plasma oscillation probe for measuring electron densities. This new method compares favorably with the more standard Langmuir probe measurements.

The electron beam ion trap now in operation in this group for the study of spectra and interactions of highly ionized species is used in both pure science (e.g., atomic lifetimes) and applications (e.g., surface modifications using highly charged ions). This new facility has been further upgraded with the addition of an ultrahigh vacuum in situ scanning tunneling/atomic force microscope for studying the effect of the interaction of ions of charge q>>30+ with silicon wafers and other surfaces. This will permit direct observation of nanoscale surface modifications by the ions without removing the sample from the vacuum, greatly extending the value of the existing diagnostics using x-ray and electron spectrometers.

Last year's report described the Laser Cooling and Trapping Group as one of the world's leaders in this very new and rapidly developing field of atomic physics, and this year the accolade was corroborated by the award of the Nobel Prize to the group's leader. This is the highest award a scientist can achieve, and the honoree, William D. Phillips, is not only the first NIST employee to be so honored, but also the first U.S. government employee to receive the physics prize.

The subject of laser cooling and trapping of atoms is broader than the name suggests and, in fact, could be called “optical manipulation ” of neutral atoms, which includes laser cooling and many other subjects. The group had several times set the record for the lowest temperature ever achieved and had set its sights on more general topics. In many cases, these studies lead further in

Suggested Citation:"5 Physics Laboratory." National Research Council. 1998. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories, Fiscal Year 1998. Washington, DC: The National Academies Press. doi: 10.17226/9515.
×

the direction of improved high-resolution spectroscopy, better atomic clocks, more atomic collision information, and further application toward atom optics.

Another area of considerable achievement comes from the ultracold collisions. The precision spectroscopy of the vibrational levels has led to a vastly improved value of the dipole moment and hence of the lifetime of the 32p state of Na. This is probably one of the most accurate measurements of the lifetime of an atomic excited state. This new form of high-resolution spectroscopy is so sensitive that the experimenters can measure the effects of retardation on the resonant dipole-dipole interaction.

The recent merger of the Quantum Metrology Group into the Atomic Physics Division appears to be successful. The new Displacement Measurement Competence project in this group utilizes a triad of interferometric methods—Fabry-Perot, Michelson, and x-ray interferometry—to establish a new standard of accuracy in distance measurements over a sizable fraction of a meter. Among the possible applications would be the location (relative to a reference point) of another point on a very large silicon wafer. A dynamic new team for subnanometer-scale motion measurement has been assembled in the last year, including collaborators from the NIST Manufacturing Engineering Laboratory. This Competence project has materially strengthened the Quantum Metrology Program. This is an extremely ambitious program and has the potential for very high payoff.

Precision gamma-ray measurements on the joint NIST-Institute Laue Langevin Guide to Available Mathematical Software (GAMS-4) spectrometer, in combination with accurate nuclear mass differences, have provided new determinations of the neutron mass and the molar Planck constant.

In a low-cost electron-spin resonance study of hydrogen impurities in one silicon sample, a discrepancy of 3 ppm in the density has been resolved. This explains the “molar volume anomaly” that has been a problem since 1994 in the group's attempt to establish a new atomic-based standard of mass, the “silicon kilogram,” to replace the artifact platinum-iridium standard kilogram housed in Paris, which is the basis for worldwide realization of the mass standard. Replacement of this artifact by an atomic-based standard should substantially reduce the drift in mass experienced by national standards worldwide.

Impact

The division continues to be responsible for three Atomic Data Centers: the Atomic Energy Levels Data Center, the Data Center on Atomic Transition Probabilities and Line Shapes, and the Data Center on X-ray Transition Energies and Wavelengths. Much of this information is being furnished and coordinated in a user-friendly way on the Internet through cooperative efforts with the laboratory's Electronic Commerce in Scientific and Engineering Data Office. To improve dissemination of the NIST databases, the Physics Laboratory has developed (in the past 3 years) a freely accessible Internet Web site with a growing number of data compilations. More than 100,000 database hits are made each month, with the number of downloads growing exponentially. The number of hits on the databases increased by a factor of 3 in 1 year, from 35,000 to 100,000 per month.

It is noteworthy that SEMATECH/Lincoln Laboratory came to the Plasma Radiation Group in this division for help with precision measurements of deep UV optical constants of

Suggested Citation:"5 Physics Laboratory." National Research Council. 1998. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories, Fiscal Year 1998. Washington, DC: The National Academies Press. doi: 10.17226/9515.
×

materials for use in the manufacture of integrated circuits and microprocessors. This is a real quality measure—NIST was not “selling” what it can do, but rather, industry came for help, recognizing superior capability.

Another example is the request by the lighting industry for data on rare earth spectra. Not only does this contribute to U.S. competitiveness in the marketplace, but it also contributes to the national goal of energy efficiency.

The thin film uniformity measurements being done in loose connection with Intel are an example of a good connection between NIST science and a critical U.S. industry. Precision measurements of the index of refraction of optical materials, including temperature dependence of this index, to part-per-million accuracy are needed for the design of fused silica and calcium fluoride lenses needed for 193 nm UV lithography of integrated circuits.

Resources

Funding sources for the Atomic Physics Division (in millions of dollars) are as follows:

 

Fiscal Year 1997

Fiscal Year 1998 (estimated)

NIST-STRS, excluding Competence

4.7

5.8

Competence

1.1

0.7

ATP

0.2

0.3

OA/NFG/CRADA

1.2

1.1

Other Reimbursable

0.2

0.2

Total

7.4

8.1

Staffing for the Atomic Physics Division currently includes 30 full-time permanent positions, of which 26 are for technical professionals. There are also 12 nonpermanent and supplemental personnel, such as postdoctoral fellows and part-time workers.

Last year's panel report noted that a training program was lacking for the next generation of researchers in the Atomic Database Program. Any new efforts to develop new talent in this area are not evident.

The panel was encouraged that the division is making an active nationwide as well as internal search for the right individual to lead the critically evaluated spectroscopic and data compilation effort and emphasizes that this unique national resource was made possible because NIST had an appropriate person who established a tradition of excellence.

Suggested Citation:"5 Physics Laboratory." National Research Council. 1998. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories, Fiscal Year 1998. Washington, DC: The National Academies Press. doi: 10.17226/9515.
×
Optical Technology Division
Mission

The Optical Technology Division stated its mission in a briefing to the panel as follows: The Optical Technology Division, by advancing knowledge and expertise in targeted areas of optical technology, will provide the highest quality services, technical leadership, and measurement infrastructure to promote the U.S. economy and support the public welfare and national defense. In the Technical Activities 3 Summary, it gives its mission as providing national measurement standards and support services to advance the use and application of optical technologies spanning the ultraviolet through microwave regions for use in diverse industries and governmental and scientific enterprises.

The mission of the Optical Technology Division, although similar in nature to those of other divisions in the Physics Laboratory, is significantly broader in scope owing to the diversity of its tasks. It provides national measurement standards for two fundamental SI units, the candela (the unit of luminous intensity) and the kelvin (the division has responsibility for the temperature scale above the melting point of silver). It develops radiometric, photometric, spectroscopic and spectrophotometric calibration services spanning a significant portion of the electromagnetic spectrum. The division provides standards and measurement quality assurance services to an ever-widening customer base, including the lighting, photographic, automotive, xerographic, and electronics industries as well as national needs in solar and environmental monitoring, health and safety, and defense. It performs state-of-the-art spectroscopic research and development that will provide new and improved standards, calibration services, and an expanding database of optical and photochemical properties of materials.

Technical Merit and Appropriateness of Work

The diversity of activities within the division ranges from basic research on the applications of light scattering as a metrological tool for the characterization of solid surfaces, to repeated and ongoing interactions with industrial-sector engineers to establish methodologies and standards for industries that are using high-intensity ultraviolet light as a processing agent. The division comprises five groups. Although organized for administrative manageability and operational accountability, the science and technology are focused on the measurement of electromagnetic energy and its interaction with matter. The division has the superb expertise needed to generate, calibrate, detect, and create standards for electromagnetic wave energy ranging from 1 to 106 wavenumbers (microwave to ultraviolet waves).

Microwave spectroscopy is being used in conjunction with laser vaporization to study the structures of metal carbides, metal silicides, and other refractory species that are important intermediates in the plasma processing industry and, additionally, are used as hardening agents in the machine tool industry. Other projects include the development of analytical tools for the monitoring of chemical agents in a variety of environments, the study of species that are important

3  

U.S. Department of Commerce, Technology Administration, National Institute of Standards and Technology, Physics Laboratory Technical Activities 1997, NISTIR 6104, National Institute of Standards and Technology, Gaithersburg, Md., 1998.

Suggested Citation:"5 Physics Laboratory." National Research Council. 1998. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories, Fiscal Year 1998. Washington, DC: The National Academies Press. doi: 10.17226/9515.
×

in atmospheric chemistry (e.g., N205), and ongoing efforts to miniaturize a FT microwave spectrometer for eventual commercialization. FT spectrometers are also replacing prism and grating instruments for use in the infrared part of the spectrum in many laboratories around the world. The availability of inexpensive computers has made it possible to realize the inherent speed advantage of interferometric spectroscopy in relatively straightforward ways. At the same time, needs for new standards are developing at a rapid pace. Research within the division is testing the radiometric accuracy of the simplest of spectroscopic measures, that of absolute transmittance. This work teaches the users of FT infrared spectroscopy a new understanding of their instruments and possible methods of error reduction. As a result, this spectroscopy is well on its way to becoming a metrological tool for a variety of applications in the near and far infrared.

The Spectroscopic Applications Group has been active in the development of infrared spectroscopic instrumentation and measurements in support of NASA's Upper Atmosphere Research Program, in the development of mid-infrared CRDS as an analytical tool, and in the construction of a fast diode system for wind tunnel and plasma diagnostics. An infrared radiometer for monitoring fire extinguishing agents with 10 ms time resolution is being developed in collaboration with the NIST Building and Fire Research Laboratory with Department of Defense funding. Theoretical efforts of the group are progressing in three separate areas, with the major part of the work focused on a Department of Energy-driven project on torsionally mediated intramolecular vibrational energy transfer. A unified vibrational quantum number for use above and below torsional barriers is being developed, using contact transformations. A second focus area is the methanol dimer, including its spectroscopy and multidimensional tunneling pathways. The third focus area deals with the development of a proper Hamiltonian to describe the energy level structure of oxygen-containing van der Waals complexes.

The Laser Applications Group continues to improve the state of the art in molecular spectroscopy for both chemical and biological applications in the mid- and far-IR spectral regions. IR absorption and nonlinear optical techniques such as sum frequency generation are being used to probe surface and interface electronic and vibrational states at metal, semiconductor, and dielectric solid and liquid interfaces. A new focus is the extension of such techniques to biological systems, in collaboration with the Biotechnology Division of the NIST Chemical Science and Technology Laboratory, with funding from the Advanced Technology Program.

During the past year, basic research on correlated photon metrology for the near infrared has been tested in terms of absolute infrared spectral radiance. The objective is to measure this radiance in an intrinsically absolute manner. Here, the infrared photon is frequency shifted into the visible where better radiometric tools are available. The results demonstrate an accuracy consistent with the estimated uncertainty of current comparison methods. When the synchrotron light source at SURF III becomes available, its enhanced stability as a light source will reduce the uncertainty in the comparison techniques. The panel urges that this research be pursued with considerable vigor.

The layering of materials is an ancient technology, and today, it is an essential process in nearly all of our manufacturing industries. Two examples illustrate the work of the division in the use of optical diagnostics for the characterization of some of the physical and chemical properties of interfaces and surfaces. The first is a study of ferroelectric and magnetic materials exhibiting GMR by Raman spectroscopy. Modern Raman spectral apparatus is well suited to the investigation of these phenomena, since the spectra change dramatically as the materials become

Suggested Citation:"5 Physics Laboratory." National Research Council. 1998. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories, Fiscal Year 1998. Washington, DC: The National Academies Press. doi: 10.17226/9515.
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electrically or magnetically active. By layering these materials with inactive components, one has a powerful investigative tool. This work is a good example of an imaginative exploratory effort.

The optical reflection of a surface at visible wavelengths depends on the incident and scattering angles as well as on the polarization of the light. The discovery of polarization signatures for microroughness, subsurface defects, and particle contaminants at NIST enabled the development of a microroughness-blind hemispherical optical scattering instrument, for which a provisional patent application has been filed. This instrument is being used for measuring nanoscale particles on silicon wafers. The results obtained to date agree well with theoretical models of the scattering, indicating that the polarization of the scattered light can be used to distinguish between microroughness and subsurface defects. This technique should improve the standardization of production line diagnostics for surface roughness of silicon wafers, which is of great importance in the electronics industry. In general, the Bi-directional Reflectance Distribution Function (bidirectional ellipsometry) deduced from these measurements provides the ability to probe many properties of surfaces, the results of which are applicable to the semiconductor, optical, photographic, and paint industries. The development of new instruments, an essential component of this research, is encouraged. The showpiece of the division's spectrophotometry, color, and appearance effort is an instrument that will combine many functions to evaluate surface color, texture, fluorescence, and other optical parameters. This work to model painted and coated surfaces is being done in collaboration with the NIST Building and Fire Research Laboratory and with the automotive and interior design industries. Additionally, an upgrade of the present spectral trifunction automated reference reflectometer instrument, currently used for reflectance and goniospectrophotometry measurements, is in the planning stages. What is not clear to the panel, however, are the intended uses of this new instrumentation: whether it is to be used primarily for measurement services, production of SRMs, or research. Priorities for this program need to be more clearly established.

Understanding the most elementary optical properties from first principles depends on the ability of theoretical physicists and computer scientists to find numerical methods for solving huge computational problems. Recently a small group in the division has calculated the index of refraction of silicon as a function of photon energy within this rubric. The agreement with experiment is very good. As the computational power of hardware improves and scientists formulate the problems with greater insight, it should be possible to theoretically engineer new optical materials and understand their function.

A new high-resolution UV laser/continuous wave (CW) molecular beam spectrometer is under construction. When completed, this instrument will be used to obtain the rotationally resolved electronic spectra of large isolated molecules and their weakly bound complexes, thereby providing extensive new data upon which the development of new standards and reference materials can be based. The appropriate personnel are in place and resources have been provided for this challenging project. The panel applauds this effort.

Worldwide there is well over $2 billion worth of high-intensity (120 W/cm to 240 W/cm) industrial UV processing units installed in photochemical and printing operations, with 40 percent of this fast-growing market in the United States and Canada. High-intensity UV light is used to change nonvolatile liquid inks and coatings to cured or dried surfaces in a myriad of applications, such as the glossy covers of magazines, coatings on fiber optics, wood finishes, and the like, imparting considerable value-added benefits to such products. In her testimony before the Senate Committee on Environment and Public Works on February 12, 1997, EPA Administrator Carol

Suggested Citation:"5 Physics Laboratory." National Research Council. 1998. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories, Fiscal Year 1998. Washington, DC: The National Academies Press. doi: 10.17226/9515.
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Browner noted that UV-cured coatings “not only reduce emissions to the EPA-required levels, but essentially eliminated emissions altogether.” The metrology in this area, however, has not kept up with the industrial acceptance of this environmentally friendly process technology. Working with industry leaders, the division has begun to address some important aspects of high-intensity UV metrology. For example, existing photometers used by industry give variable results and tend to burn out when repeatedly exposed to such high-intensity sources. The division has found two new bases for UV-sensing devices based on nitrided silicon and on platinum-silicon that endure such high-intensity exposure over extended periods of time. The objective of the division is to develop durable, accurate, low-profile sensors for this market area. The panel was pleased to note the rapid acceptance by the division of this technological challenge. The strategic plan was reviewed and upgraded by the division in January 1998. The determination of the balance between basic and directed research and service activities often is contentious. The division is commended for its continuing self-assessment as represented by the planning document.

Impact of Programs

The division's response to the need for the development of rapid thermal controls associated with high-temperature processing for silicon chips by the semiconductor industry is commendable. This process is an essential enabling technology in the Semiconductor Industry Association Roadmap, 4 which discusses technology necessary to produce computer chips with minimum feature sizes of 180 nm. In the design of lithographic instruments for printing of these feature sizes, Lincoln Laboratories proposed to specify quartz and calcium fluoride optics. Chip designers found that the critical data for these two materials, the indices of refraction at the ultraviolet wavelength of 180 nm, were not available. With its reservoir of technical expertise, the division quickly assembled a team to measure these material constants and their temperature dependence to the required accuracy of better than 1 part in 105, permitting lens designers to proceed.

As another example of impact, the division highlighted the following for the panel. Recent regulatory concerns about the quality of roadside signage as a critical safety element led the Federal Highway Administration and manufacturers such as 3M to request NIST support for the development of standards in retroreflectance, a measure of how effectively a surface reflects light. The development of such standards would also facilitate export and acceptance of these products overseas. NIST 's previous capability in retroreflectance had disappeared over time due to equipment obsolescence and retirement of staff. As a result of the expressed need, the division is rebuilding capability in this area, hiring a new staff member to develop the facility needed to respond. The panel noted that this example highlights the need to maintain support in critical areas, so that the capability is available for NIST to respond quickly to such requests.

This group is commended for the increase in the number and availability of SRMs offered in the past year. Still, the current backlog of orders indicates there is much greater demand for some standards than can be met with the current production schedule, and there is still a need for

4  

Semiconductor Industry Association, The National Technology Roadmap for Semiconductors: Technology Needs, Semiconductor Industry Association, San Jose, Calif., 1997.

Suggested Citation:"5 Physics Laboratory." National Research Council. 1998. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories, Fiscal Year 1998. Washington, DC: The National Academies Press. doi: 10.17226/9515.
×

better planning and coordination between the producers of such SRMs and the Technology Services unit that sells and markets them.

Resources

Funding sources for the Optical Technology Division (in millions of dollars) are as follows:

 

Fiscal Year 1997

Fiscal Year 1998 (estimated)

NIST-STRS, excluding Competence

5.4

5.0

Competence

0.6

0.6

ATP

0.3

0.6

Measurement Services (SRM production)

0.1

0.2

OA/NFG/CRADA

4.0

4.2

Other Reimbursable

0.5

0.5

Total

10.9

11.1

Staffing for the Optical Technology Division currently includes 46 full-time permanent positions, of which 41 are for technical professionals. There are also 13 nonpermanent and supplemental personnel, such as postdoctoral fellows and part-time workers.

The division is successfully responding to the needs and requests of industry and is sustaining a superb research program; however, to meet the growing array of activities, additions to the technical staff ought to be made in selected areas. In addition, to maintain the quality of the research in optical properties of materials and to respond to the pressing need for expanded calibration services and the development of new SRMs, enhanced resources might be made available to bring more instrumentation to this important technology.

Ionizing Radiation Division
Mission

The Ionizing Radiation Division states its mission as follows: The division has the responsibility within NIST for providing national leadership in promoting accurate, meaningful, and compatible measurements of ionizing radiation (x rays, gamma rays, electrons, neutrons, energetic charged particles, and radioactivity).

The mission statement as provided by the division adequately embraces the overall goals and objectives of the division. The Ionizing Radiation Division epitomizes the anticipated strong relationship between NIST and the scientific/industrial community. The three groups in this division—the Radiation Interactions and Dosimetry Group, the Neutron Interactions and

Suggested Citation:"5 Physics Laboratory." National Research Council. 1998. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories, Fiscal Year 1998. Washington, DC: The National Academies Press. doi: 10.17226/9515.
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Dosimetry Group, and the Radioactivity Group—enjoy deep and long-standing interactions with their constituent communities. Although the division is performing admirably with respect to its stated mission, greater emphasis needs to be placed on meeting NIST's overall objectives of becoming the world-class calibration and technical resource laboratory in the field of ionizing radiation.

Technical Merit and Appropriateness of Work

The Radiation Interactions and Dosimetry Group continues to pursue a broadly diversified program spanning metrology of ionizing radiation to development of new dosimetry tools and techniques. The recent increased activity in establishing a water-based, high-energy photon calibration technique is advancing rapidly. NIST is working closely with national professional organizations such as the American Association of Physicists in Medicine and collaborating with international organizations such as the Bureau International de Poids et Measures to ensure a stable and fully useful metrology program. To bring this work to closure, NIST could actively integrate the network of secondary calibration providers into this program. This would serve to stabilize and integrate the new metrology effort. Such a leadership role by NIST is essential.

The acceptance and industrial use of enhanced dosimetry methods involving alanine can be facilitated by putting forth industry-usable documentation, listing in simple terms the costs of equipment and sources for alanine-containing dosimetry films and pellets. To date, meritorious technical work in this field, although generally recognized for its significance and value, will not have impact unless such resource needs are clearly spelled out and widely disseminated in the industrial-user community. Quality assurance issues involving the more historic radiochromic films disturb industrial users and continue to be addressed; a resolution of such issues would be beneficial. These efforts meld into the need to strengthen the technical infrastructure in support of secondary calibration laboratories.

The inclusion of a new scientist in the theoretical dosimetry effort appears to have strengthened the program. Nationally, researchers look to NIST to provide seminal evaluations of basic data and dosimetry techniques for the full range of photon and lepton energies. Although this is a mature scientific field, new applications in industry and medicine generate a continuing need for such efforts. Movement to disseminate this on the World Wide Web is productive. An important corollary would be to evaluate what data are needed and in what form they should be published. Such activities are a national resource widely used by the scientific community, hence the importance of a coordinated and effective dissemination.

During the last year, major advances in the experimental program of the Neutron Interactions and Dosimetry Group occurred. This is especially true for the interferometry and optics efforts as well as the large collaboration investigating the neutron lifetime. Facilities are fully functional and unique in the United States. Research collaborations with universities and other national laboratories are very extensive and serve to demonstrate the quality of the program. Interestingly, the research, despite its very fundamental nature, enjoys immediate application, an example being the ability to microscopically image hydrogen density for industrial products, such as fuel cells. Another example concerns the group's efforts in producing a reliable hyperpolarized source of helium-3. The applications in biomedical imaging are substantial, as its use permits the imaging of cavities such as the lungs or sinuses to much higher quality than previously possible.

Suggested Citation:"5 Physics Laboratory." National Research Council. 1998. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories, Fiscal Year 1998. Washington, DC: The National Academies Press. doi: 10.17226/9515.
×

This group and its facilities are a national resource and are providing and will continue to provide international leadership in this area of materials science.

Neutron dosimetry work is undergoing a gradual change in paradigm. The major capability revolves around reactor-based fluences and spontaneous fission sources. Several well-defined neutron fields are available and used by a spectrum of customers from industry and government agencies. A burgeoning program in reactor materials dosimetry is proving to be increasingly valuable to the reactor industry. NIST could take a technical leadership role in this area by building strong collaborations with industrial partners.

In contrast to this strong record of accomplishment, neutron calibration work above 1 MeV for nonfission neutron fields suffers from a lack of capability nationally and certainly at NIST. Although such neutron fields are uncommon, there is concern about their effects on electronic systems in the space environment. NIST should consider defining the need in this area, perhaps addressing a multifacility program available nationally and guided by NIST.

The final area of effort is the classical competence in cross-section evaluation and determination. The knowledge base below 20 MeV is for the most part well defined and undergoing modest incremental changes, but above 20 MeV there is a paucity of information. Economy of scale dictates an international multi-institutional program. NIST 's presence in this process is important. Understanding that the emphasis and bulk of contributions will not be from NIST, the role of NIST must be well defined and targeted.

The Radioactivity Group continues to enjoy dynamic and productive activity covering a broad spectrum of science and industrial expertise. The group has a very strong and multidisciplinary effort in brachytherapy and intravascular applications. NIST is rapidly establishing a national leadership role in metrology and dosimetry for medical applications. NIST efforts to sponsor and organize topical symposia articulating the essential needs in the area and defining the interface between science and medicine could have notable societal impact. Radioactivity metrology on other fronts continues apace. As the resonance ionization mass spectrometer comes on line, activity determinations in new regions of sensitivity are possible. This advance complements the SRM efforts and will advance the national effort in radioactive waste management by allowing better in situ measurements of radioactivity. The group 's efforts to develop radionuclide standards for positron emission tomography (PET) are timely, given the recent approval by the Food and Drug Administration (FDA) of PET radionuclides for diagnostic procedures. The short physical half-life and spectrum of biochemical agents make this effort important and challenging.

Communications and relationships with the industrial community in this effort are excellent. For example, the joint effort with the Nuclear Energy Institute has proved very beneficial to NIST and the industrial community. Similar collaborations exist for the SRM Program.

A specific program plan is needed in the Radiation Interactions and Dosimetry Group to define the issues in technology transfer to industry of alanine dosimetry work. Similarly, a specific plan is needed in the Radioactivity Group to delineate the extent and diversity to which SRMs will be needed for isotopes admixed in diverse media, e.g., soils, tissue, and so on.

Finally, there are increasing opportunities for technology development that combine the use of ionizing radiation with biomedical applications. An obvious example is the use of biomaterials that are enhanced for magnetic resonance (MR) response to assist the uses of radioactive stent placement under MR-guided imaging. These and applications in other NIST

Suggested Citation:"5 Physics Laboratory." National Research Council. 1998. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories, Fiscal Year 1998. Washington, DC: The National Academies Press. doi: 10.17226/9515.
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divisions suggest that an experienced biomedical engineer could facilitate interdivisional activities in this area and greatly advance technology transfer into the commercial sector.

Impact of Programs

As noted above, the scientific and technical work done by each of the three groups in the Ionizing Radiation Division is highly regarded nationally and, on an increasing level, internationally as well within the scientific and technical community. However, to date there have been limited attempts to quantify the industrial impact and economic value of these programs. The division did contract for an economic evaluation of radiopharmaceutical research at NIST during 1997. A cost-benefit ratio of 1:97 was estimated. Other activities of the division, such as the cooperative development (with the University of Wisconsin and the FDA) of reference beams and calibration procedures for mammography testing, have been noted before Congress. In spite of being involved in many strategic areas with significant societal impact, the division suffers from having a quiet reliability without adequate public recognition of its important role in science and technology. For example, the SRM program would benefit from a macroeconomic study of its long-range impact.

The division has been responsive to national needs as defined by the Council on Ionizing Radiation Measurements and Standards, a coordinating council involving industry, government, and academic constituencies. Moreover, NIST routinely takes a leadership role in establishing appropriate metrology standards and identifying and discovering measurement procedures to ensure the highest level of metrology. These contributions are nicely complemented by fundamental research activities, especially those employing the Cold Neutron Facility at the NIST Center for Neutron Research.

The intended shift in operating paradigm to rely on greater use of telecommunication/ electronic data transfer, e.g., via the Internet, should be paced and thoughtfully reviewed with respect to whether such documents as certificates of calibration using remote data interpretation will indeed be legally valid and can in fact be performed using such telecommunication/electronic methods. A plan for the overall use of telecommunications/electronic data transfer would help establish the credibility of this format in the ionizing radiation community and may uncover issues not yet addressed.

Resources

Funding sources for the Ionizing Radiation Division (in millions of dollars) are presented below:

Suggested Citation:"5 Physics Laboratory." National Research Council. 1998. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories, Fiscal Year 1998. Washington, DC: The National Academies Press. doi: 10.17226/9515.
×
 

Fiscal Year 1997

Fiscal Year 1998 (estimated)

NIST-STRS, excluding Competence

4.1

4.2

Competence

0.3

0.0

ATP

0.1

0.3

Measurement Services (SRM production)

1.1

1.4

OA/NFG/CRADA

1.1

1.4

Other Reimbursable

0.8

0.8

Total

6.6

6.8

Staffing for the Ionizing Radiation Division currently includes 35 full-time permanent positions, of which 31 are for technical professionals. There are also four nonpermanent and supplemental personnel, such as postdoctoral fellows and part-time workers.

The entire Radiation Physics Building needs to be reglazed and waterproofed below grade. Driving rainstorms create leaks in offices and laboratories, and there is seepage in the below-grade vaults used to house accelerators.

Although the existing Medical Industrial Radiation Facility (MIRF) has been useful, it has several inadequacies. Specifically, for medical metrology, the beam delivery system differs radically from the modern range of linacs. This greatly complicates the transfer of measurements to the medical community, both in the electron and photon modes. Modification of the MIRF to more closely approximate a modern linac would be technologically challenging; hence, a modern, state-of-the-art, multienergy, multimode medical linac (at least the treatment head) should be acquired. Such an accelerator might also address some of the industrial needs for a high-energy electron source for the study of industrially relevant x-ray target materials.

Industry needs for a high-current national reference beam could be met by replacing outdated equipment with a new 500 to 800 keV high-current accelerator. This accelerator would provide high-intensity electron beams comparable to those used in industry. Industry is well aware of dose-rate effects on materials and processes and the need for a high-current reference source.

Although existing x-ray sources are generally of sufficient capability to serve the metrology needs, an upgrade to a fully computer-driven data acquisition and control system would be very important. The present facilities are a result of a 30- to 40-year evolutionary process resulting in a cumbersome and difficult control metrology facility.

The division's cobalt-60 source has a known asymmetry that poses serious problems for water-based calorimetry. This needs to be changed and corrected.

All three sections of the division are fundamental to the U.S. program in the metrology of ionizing radiation. However, capital resources used in the photon/electron interaction areas are not state of the art and thus constrain the division's striving for preeminence. To this end, the division needs a specific capital plan that outlines and quantifies one-time expenditures needed to bring state-of-the-art equipment into the division and to retire equipment that is substandard in today's scientific and technical community. Without such upgrades, NIST's facilities will be less than state of the art or at lower than industry-acceptable levels and not suitable for leading-edge

Suggested Citation:"5 Physics Laboratory." National Research Council. 1998. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories, Fiscal Year 1998. Washington, DC: The National Academies Press. doi: 10.17226/9515.
×

technical work that will carry NIST into the 21st century. A delay of even a few years will threaten this program.

Besides replacement of personnel who were lost due to attrition and retirement, the Ionizing Radiation Division could benefit from a full-time staff member devoted to the theoretical aspects of radiation interactions and an experienced biomedical engineer familiar with materials and the biological aspects of radiation effects. The laudatory involvement of the Ionizing Radiation Division in a variety of international standards issues will stretch and extend existing personnel resources throughout the division. Staff will be needed in order to sustain programs while more senior members participate in such international activities.

Time and Frequency Division
Mission

The Time and Frequency Division stated its mission as supporting U.S. industry and science through provision of measurement services and research in time and frequency technology. The mission conforms well to both those of the Physics Laboratory and NIST, and the division 's programs conform very well to the mission statement.

Technical Merit and Appropriateness of Work

The Time and Frequency Division's program probably ranks overall as the best in the world. The division currently maintains an excellent operating primary frequency standard, means of frequency and time dissemination, and research and development leading to new, much higher performance standards in both the optical and microwave ranges. Some of this work is important to the development of commercial frequency standards, which are widely used in time-scale generation in national standards laboratories. A number of commercial cesium standards as well as hydrogen masers are used to generate a carefully optimized time scale that is disseminated via a number of means. There is very good work on time dissemination via networks and on time and frequency comparison via the Global Positioning System (GPS) and two-way satellite time transfer. This is important to industry because of the increasing accuracy requirements for time synchronization in digital communications systems. There is also excellent effort in the area of lasers, particularly stabilized diode lasers for excitation and cooling of atoms or ions in advanced frequency standards. Finally, low-flicker noise amplifiers and oscillators and spectrally pure frequency sources under development are important for the high-performance frequency standards and have commercial importance.

The accuracy of the optically pumped NIST7 cesium beam frequency standard is currently still evaluated at ±5 × 10−15, with further improvement promised soon. The copy of NIST7 that the division constructed for the Communications Research Laboratory in Japan is partially operational, and some of the improvements in it and its electronics will be retrofitted to NIST7. These improvements, along with new software to make the evaluations much less labor intensive and more reproducible, should improve the accuracy considerably. It will also increase the weighting given NIST7 in the determination of the international atomic time scale.

Suggested Citation:"5 Physics Laboratory." National Research Council. 1998. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories, Fiscal Year 1998. Washington, DC: The National Academies Press. doi: 10.17226/9515.
×

Although behind the French, the division continues its progress in building a cesium atomic fountain standard. The Atomic Physics Division is addressing transverse cooling for the fountain standard, an important contribution that should provide a better signal-to-noise ratio and smaller systematic errors, giving NIST a performance advantage. Collaboration continues with Politecnico De Torino on design of a suitable microwave cavity with low-distributed phase shift.

Funding has been received for a collaborative effort to develop a cooled cesium primary frequency standard for the International Space Station with an accuracy of about ±1 × 10−16. The panel was pleased to note that work is progressing, both in house and in collaboration with Stanford University, on low-noise flywheel oscillators, including a laser-pumped rubidium gas cell standard. These devices are essential to realizing the stability performance promised by the fountain and other high-performance frequency standards.

Work on a simplified, robust, RF-to-optical frequency chain is also very encouraging. An important element of this is a novel periodically poled lithium niobate crystal that can be used as a mixer as well as a harmonic generator.

The trapped ion frequency standard using a linear string of seven cooled 199Hg ions has demonstrated a stability of about 1 × 10−14 for an interrogation time of 100 s at an averaging time of 1000 s. Increasing the number of ions should lead to record stability. Estimates now are that an accuracy of about ±1 × 10−16 can be achieved. The present limitation in accuracy is due to magnetic fields at the trap drive frequency, caused by unbalanced capacitive currents to the quadrupole electrodes due to asymmetries. Even better stability may result from extending the same low-temperature linear trap techniques to the 282 nm electric quadrupole 199Hg transition.

The division continues to investigate correlated states in ion strings. Two ions have now been suitably trapped, leading to demonstrations of two quantum bits. This work has application not only to quantum computation but also to improving frequency stability in trapped ion standards. Development is also proceeding on miniature, high-dimensional accuracy traps to confine the ions strongly with resulting improved performance in both frequency standards and trapped ion quantum computing.

Work in the area of phase and amplitude noise and electronics for frequency standards and clocks continues to lead the world. Recent progress has been made in understanding flicker-of-phase noise and its reduction in amplifiers, leading to improvements in noise of better than 20 dB. This is important for amplifiers as well as low-noise oscillators. In addition, good progress has been made in developing low-noise synthesizer chains and regenerative frequency dividers working in the microwave range. Many of the results from this group have direct and important applications in industry. The group also performs many calibrations for industry.

The stability of the NIST time scale, AT1, has continued to improve over the last year. Several hydrogen masers that are well characterized for drift have recently been integrated into the scale with consequent stability improvement. The stability at 1-day averaging is about four times better than that of a year ago.

Time comparison via the conventional GPS common-view technique is now at the level of a few nanoseconds. Work is progressing on common-view carrier phase measurements that will allow frequency comparisons to a one part in 1015 in 1 day and, if cycle ambiguity can be resolved, time comparisons to better than 1 nanosecond. The group doing this work is also involved in evaluation of a new version of a commercial GPS receiver and time comparisons over the Internet. The Internet service receives about 3 million hits per day and provides time within about

Suggested Citation:"5 Physics Laboratory." National Research Council. 1998. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories, Fiscal Year 1998. Washington, DC: The National Academies Press. doi: 10.17226/9515.
×

2 ms over long paths. Work is also starting on a technique of providing an authenticated time-stamp service over the Internet, which could be very important to industry and commerce.

In response to industry needs for improved synchronization of high-speed information transfer, the division has led an effort to integrate industry techniques with those developed by the metrology community through a series of workshops that have attracted more than 60 participants per year. A related project has developed a two-way time transfer system using Synchronous Optical NETwork optical fiber techniques for time transfer on the Internet.

The upgrade of the equipment and power level of the transmission stations WWV and WWVB in Fort Collins and WWVH in Hawaii nicely coincides with the production and sales by numerous manufacturers of clocks and watches synchronized to these broadcasts using very small receivers. The provision of a 500-kW emergency power generator at Fort Collins is an important potential support of the reliability of those broadcasts.

The division has also achieved a written agreement with the U.S. Naval Observatory that delineates responsibilities of each institution in timekeeping, avoids overlaps in programs, and achieves a number of other worthwhile goals. This is an excellent achievement after many years of independent efforts that sometimes resulted in friction between the two authorities.

The technical work of the division is excellent and is mostly at or leading the state of the art. The planning of the programs appears to be very good in view of the results.

Impact of Programs

The division has published more than 70 papers and given more than 80 invited talks in the last year. Their content represents the division work very well. One area that is being worked on quite hard is that of publishing the evaluation and error budget details of NIST7. It is the panel's understanding that a long, detailed paper on this will be published reasonably soon.

The division's impact on industry continues to be strong. Companies regularly use the technical content in the division's publications and talks. This is particularly true in the areas of commercial quartz oscillators and atomic frequency standards. There is some collaborative work with industry in the areas of gas cell frequency standards and tunable external cavity diode lasers. Calibrations are also important.

In addition, the division is coupled to industry in a number of areas including providing various types of time and frequency dissemination; calibration services; consultation on low-noise amplifiers and oscillators; development of a high-power, narrow-bandwidth, frequency-tunable diode laser; collaboration on design, development, and testing of a miniature cesium gas-cell clock; and collaboration in investigating different types of optical and nonoptical pumping techniques for alkali vapor clocks. The division works to understand industry's present and future needs and satisfy them. It and its scientists are highly respected and well recognized as leaders in most aspects of the time and frequency field. They have very high visibility in the national and international community and contribute strongly to a number of standards committees.

Reosurces

Funding sources for the Time and Frequency Division (in millions of dollars) are presented below:

Suggested Citation:"5 Physics Laboratory." National Research Council. 1998. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories, Fiscal Year 1998. Washington, DC: The National Academies Press. doi: 10.17226/9515.
×
 

Fiscal Year 1997

Fiscal Year 1998 (estimated)

NIST-STRS, excluding Competence

5.2

5.6

Competence

0.6

0.3

ATP

0.1

0.0

OA/NFG/CRADA

1.9

1.8

Other Reimbursable

0.7

0.7

Total

8.5

8.4

Staffing for the Time and Frequency Division currently includes 38 full-time permanent positions, of which 33 are for technical professionals. There are also 11 nonpermanent and supplemental personnel, such as postdoctoral fellows and part-time workers.

Resources seem to be adequate at this time. Additional space in the main NIST building at Boulder will become available when the National Oceanic and Atmospheric Administration moves and NIST takes over their old building. The division expects to get about 10,000 sq ft of laboratory space in the main building. In addition, the division may be able to consolidate its operations into one wing.

MAJOR OBSERVATIONS

The panel offers the following major observations.

  • The technical merit of the programs ongoing in the Physics Laboratory is very high, and many of the laboratory's efforts are at or define the state of the art in their field, as exemplified by NIST researcher Dr. William Phillips sharing the 1997 Nobel Prize in Physics for his work in developing laser cooling and trapping of atoms.

  • The laboratory's work in databases is essential to developing and modeling industrial processes and understanding the earth's environment and in many other applications. Keeping these databases current will require a continuous effort—it cannot be done unless staff are allowed the time and resources to keep fully up-to-date with the relevant experimental measurements and theoretical calculations.

  • The laboratory's programs are generally quite appropriate and can respond rapidly to specific industry requests when they arise. However, it was not clear to the panel whether program priorities had been chosen based first on industry needs, rather than on laboratory capabilities.

  • The laboratory's programs still suffer from the deterioration in physical plant described in the panel's previous report. Scientists are forced to spend time and effort on expensive work-arounds to obtain the temperature control, humidity control, vibration control, and cleanliness that are necessary for their high-precision measurements.

Suggested Citation:"5 Physics Laboratory." National Research Council. 1998. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories, Fiscal Year 1998. Washington, DC: The National Academies Press. doi: 10.17226/9515.
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REVIEW OF JILA

This biennial assessment of the activities of JILA, an institute administered jointly by the National Institute of Standards and Technology and the University of Colorado, is based on a meeting of the Subpanel for JILA in Boulder, Colorado, on January 29–30, 1998, and on documents provided by the institute. Note that 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.

Members of the subpanel included F. Fleming Crim, University of Wisconsin –Madison, Chair; A. Paul Alivasatos, University of California, Berkeley; Robert W. Field, Massachusetts Institute of Technology; George W. Flynn, Columbia University; E. Norval Fortson, University of Washington; Frances A. Houle, IBM Corporation; H. Jeffrey Kimble, California Institute of Technology; Margaret M. Murnane, University of Michigan; Steven S. Vogt, University of California Observatories/Lick Observatory; and Carl A. Zanoni, Zygo Corporation.

Mission

According to JILA personnel, the mission of the NIST Quantum Physics Division is to support the U.S. economy by working with industry and academe to advance the frontiers of measurement science and commercialize the results of its endeavors. In pursuit of this mission, the division performs the following tasks:

  • Develops the laser as a precise measurement tool,

  • Determines fundamental constants and tests the fundamental postulates of physics,

  • Exploits Bose-Einstein condensation (BEC) for metrology and low-temperature physics,

  • Devises new ways to direct and control atoms and molecules, and

  • Characterizes chemical processes and their interactions with nanostructures.

The division's efforts in precision measurement, laser stabilization, BEC, control of atoms and molecules, and the characterization of chemical processes are all closely aligned with the needs of NIST and the execution of the NIST mission. The measurements and standards program promotes the U.S. economy and public welfare by providing technical leadership for the national measurement and standards infrastructure and by assuring the availability of essential reference data and measurement capabilities. The Quantum Physics Division has a proper understanding of its role within NIST and performs its functions well.

The mission statement does not include astrophysics research among its goals because the NIST Quantum Physics Division no longer supports the Astrophysics Fellows and activities in JILA. During the site visit, the panel learned that the institute has begun planning for the possible departure of the Astrophysics Fellows from JILA to other homes within the University of Colorado. The Resources section discusses important issues related to this transformation.

Suggested Citation:"5 Physics Laboratory." National Research Council. 1998. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories, Fiscal Year 1998. Washington, DC: The National Academies Press. doi: 10.17226/9515.
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Technical Merit and Appropriateness of Work

The technical merit of the work at JILA is superb and is on par with the best in the world. In the subpanel's view, the accomplishments and plans of JILA represent the result of the formation of a “cluster of excellence.” The connection among most of the programs is real and strong, and such associations enhance each project and produce collaborations that make JILA unique.

Precision measurement and metrology has unified and enlivened a wide range of work at JILA throughout its history. This research continues to span a broad spectrum, from measurements of parity nonconservation in atomic physics to progress in laser stabilization and optical frequency standards to the absolute determination of the Newtonian constant of gravitation. A principal unifying theme remains the development of new measurement techniques based on the considerable expertise in optical physics at JILA. One example out of many is the invention at JILA of the Pound-Drever-Hall technique for laser stabilization, which has become an essential tool throughout laser-based science. A recent achievement that also resulted from the unique expertise available at JILA is the remarkably precise measurement of parity nonconservation in the cesium atom, completed just this past year. In this work, a small-scale experiment probes fundamental electroweak physics well beyond the energies available at the largest high-energy accelerators.

To describe and assess the merit and accomplishments of the programs at JILA, the subpanel has provided some introductory comments and two illustrative examples followed by more systematic descriptions of the five areas of activity at JILA. The intention is to illustrate the excellence of the organization, briefly document some accomplishments, assess the appropriateness of the programs, and anticipate future opportunities and challenges.

A Cluster of Excellence From the perspective of the external scientific community as embodied by the subpanel, JILA is more than a collection of outstanding scientists. It is a national resource that has time and again created enabling capabilities for the benefit of the scientific enterprise. By way of diverse associations among the Fellows, JILA has influenced the advance of science and technology profoundly, especially with respect to the development of technical tools and their generous dissemination. In fact, enlightened self-interest may account for the broad base of support that JILA enjoys in the scientific community, even in the face of generally diminishing funding for basic research. The subpanel sees the long-standing programs in precision measurement and metrology as essential forces in creating the high standing and impact of JILA. Long-term, stable support and JILA's unique infrastructure not only have produced spectacular scientific advances but also have driven the development of technical tools that help fulfill the mission of NIST and enable research across the nation and the world. The broad-based practical consequences and high-quality science growing out of the cluster of excellence at JILA are a theme of this report.

Illustrative Examples. There are many examples of the integration of expertise from different areas leading to dramatic and important scientific and technical advances at JILA. The 1996 report, for example, emphasized the first laboratory observation of BEC. In this year's assessment, the subpanel has chosen to describe briefly two examples that illustrate connections among precision measurement, optics, and chemical physics expertise that have created

Suggested Citation:"5 Physics Laboratory." National Research Council. 1998. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories, Fiscal Year 1998. Washington, DC: The National Academies Press. doi: 10.17226/9515.
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approaches and devices that enable advances in fundamental science and technology. These two advances, a new spectroscopic technique and a new radical source, happened largely because of the proximity of scientists with complementary expertise working within the cooperative environment of JILA.

The Noise-Immune Cavity-Enhanced Optical Heterodyne Molecular Spectroscopy (NICE-OHMS) technique is a product of 30 years of tool making by a JILA Fellow. NICE-OHMS has achieved a world-record fractional absorption of 1 part in 1013 (at sub-Doppler resolution). NICE-OHMS will have many applications in spectroscopy, studies of intramolecular dynamics, and detection of trace species. It combines a stabilized cavity, an ultrastable scanned laser, and frequency modulation (FM), all techniques pioneered at JILA. In 1969, a saturation dip in methane (CH4) was used to create an ultrastable laser at 3.39 µm. The year 1979 brought the invention of the FM technique, wherein a radio-frequency-driven electro-optic modulator creates a matched pair of oppositely phased sidebands on the laser frequency. These sidebands provide a basis for many optical tricks, from locking the longitudinal mode of a cavity to a laser frequency, to shot-noise-limited detection of differential absorption between the two sidebands. By introducing the frequency-modulated beam into a cavity, where the cavity length is locked to the laser center frequency and the radio-frequency offset of the sidebands is locked to the free spectral range of the cavity, one obtains the most sensitive absorption spectrometer in existence. Because molecules are subjected to two counterpropagating beams of radiation, a sub-Doppler saturation dip lineshape results, much like that employed in the CH4 stabilized 3.39-µm laser from 30 years earlier. NICE-OHMS, by advancing the limits of resolution at ultrahigh sensitivity by several orders of magnitude, will have an enormous impact on chemical physics (and forensics), although it is currently impossible to predict the specific directions and discoveries that will result from this advancement.

The pulsed slit jet radical source is a new development that provides a way of forming an intense, translationally cold beam of radicals. The relatively long slit (5 cm) provides a good absorption path and reduces transverse Doppler broadening, making the technique ideal for both ultrahigh-resolution absorption spectroscopy and for generation of femtosecond pulses of x rays by harmonic generation. When the work that would lead to this breakthrough began in 1984, the primary goal was to build the best possible source for high-resolution absorption spectroscopy of van der Waals cluster molecules. With the substantial involvement of the JILA machine shop in design and fabrication, the first pulsed slit jet absorption spectrum was published within a year. Many laboratories all over the world are now using pulsed slit jets, built from the latest machine drawings out of JILA in order to do absorption spectroscopic studies of a wide variety of systems. Most recently, by striking a discharge inside the slit jet, JILA scientists have built the best and most versatile source of ions, radicals, and cluster ions. In typical JILA fashion, another group at the institute has adapted a 1 kHz pulsed slit jet to obtain a gas-phase harmonic generation scheme that will soon provide a tabletop source of femtosecond x-ray pulses. The unique JILA combination of chemical physics and nonlinear optics expertise continues to provide major technological advances in totally unpredictable areas.

Assessment of Research Areas. The cases described above are only two examples of the high-quality work performed at JILA. In the following sections, the subpanel discusses five broad areas of research: fundamental and precision measurements, optical and nonlinear optical physics,

Suggested Citation:"5 Physics Laboratory." National Research Council. 1998. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories, Fiscal Year 1998. Washington, DC: The National Academies Press. doi: 10.17226/9515.
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materials interactions and characterization, atomic and molecular interactions and chemical physics, and astrophysics.

Fundamental and Precision Measurements. The first BEC in a gas was observed at JILA in the spring of 1995 using trapped rubidium (Rb) atoms. This accomplishment became the centerpiece of the 1996 subpanel assessment. Two years later, the extent of new research launched by this discovery is evident. Eight groups worldwide have observed BEC in atom traps, many more groups are actively trying to see BEC, and journals are filled with reports from theoretical groups now working in the field. Potential applications of BEC, such as atom lasers, are widely discussed and are under active study at JILA and elsewhere. In recent JILA research, the BEC group elucidated the fundamental thermodynamics and coherence properties of the condensates and observed a type of quantum beat note in the first mixed species condensates (using different spin states of 87Rb) that is reminiscent of the Josephson junction in superconductivity.

Just 1 year after the BEC discovery, a different JILA experiment made big news, again reaching far beyond the realm of atomic physics. After 10 years of effort, JILA scientists completed a measurement of atomic parity nonconservation in the cesium atom, accurate to 0.35 percent. This is a truly remarkable achievement in high-precision atomic physics. This table-top experiment probes the nuclear and elementary particle physics frontier and tests the existence of particles that are too heavy to be created in the highest energy accelerators now available. In the domain of atomic physics itself, the cesium parity nonconservation results are likely to stimulate advances in atomic theory and spectroscopic studies to improve on the current cesium calculations. This experiment exemplifies the standards of precision and technological innovation that are hallmarks of JILA.

The unification of science and technology at JILA can also produce commercial benefits. An example is the development of ultralow-loss mirrors, which produce over 50,000 reflections. These mirrors were perfected by JILA scientists in collaboration with Research Electro-Optics, Inc., and have become the industry and commercial standard. Basic metrology remains a strong program at JILA, and research in laser stabilization and optical standards continues to advance. An infrared laser based on Nd:YAG was locked to a narrow molecular line of iodine and attained unprecedented laser stability of 5 × 1015, by far the best achieved worldwide. In the subpanel's view, the coupling between such precision work and the other areas of research at JILA sets this institute apart. The strength in fundamental metrology, especially in optics and lasers, is the bedrock of JILA, and no other U.S. program could produce the sort of innovations that come out of JILA.

Optical and Nonlinear Optical Physics. The optical science and technology effort at JILA is excellent. The work fits well in the mission of NIST, in that it has strong potential impact on industry and will also lead to the development of new measurement techniques and standards. In addition to performing fundamental and applied research in optics, the institute scientists provide essential enabling technology for precision measurement work at JILA and beyond. For example, the development of the atom hose, in which light beams guide atoms through fibers, promises to be the basis of atom interferometers. A major success story in the area of nonlinear optics is the development and characterization of fiber sensors and photorefractive materials and devices. These very robust sensors tolerate hostile environments and, thus, have wide application in industry. JILA is now testing such sensors for robotics and automobile engine diagnostic

Suggested Citation:"5 Physics Laboratory." National Research Council. 1998. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories, Fiscal Year 1998. Washington, DC: The National Academies Press. doi: 10.17226/9515.
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applications. Only by understanding the precise, fundamental interaction of light and matter, and the behavior of novel materials under external stresses, could scientists develop these new generation probes. The creation of these fiber sensors and photorefractive materials is an example of the ability of JILA to take ideas from the research laboratory into real-world industrial applications.

JILA has recently added two new staff members in ultrafast optics and applications of ultrafast pulses to materials science. Ultrafast optics is a rapidly growing field with a host of scientific opportunities and challenges, and JILA is positioning itself to be a leader and national resource in this area. Ultrafast optics is a very appropriate area of investigation for JILA because precise knowledge of nonlinear optical constants of materials, of how to characterize ultrashort pulses accurately, and of the interaction of short pulses with materials has consequences in areas as diverse as micromachining, laser surgery, nonlinear microscopies, optical communications, and future laser-based high-energy electron and photon sources. Precise measurements of nonlinear pulse propagation in materials are already under way, adding much-needed understanding to ultrafast nonlinear dynamics. Finally, workers at JILA are using new nonlinear optical techniques to generate coherent light throughout the visible and x-ray regions, and such sources will have a great impact on the materials science and chemical physics efforts at JILA. There is a strong potential for these efforts in nonlinear optical techniques to duplicate the great synergistic relationships between optics and precision measurements. Such associations have led to BEC and many other achievements.

Materials Interactions and Characterization. Materials-related research, a relatively new part of JILA's spectrum of activities, has developed several strong themes in conformance with the expertise of the Fellows and of the newly hired Fellow-track NIST employees in optics and precision measurements. The primary focus is on development of measurement techniques rather than on synthesis of new materials or technology development. The themes fall into two groups: ultrahigh-resolution optical measurements in space and time and diagnostics for characterization of semiconductor processing reactions. In the first area, two separate experiments are developing near-field scanning optical microscopy. One uses femtosecond pulses to follow the time evolution of localized light emission from solids, and the other uses field enhancements from an atomic force microscopy tip to perform spectroscopy on single molecules. Complementary experiments being set up by the new NIST staff member use ultrafast techniques to allow the study of structure and excitation dynamics in solids and at interfaces. (This work is also mentioned in the section on Optical Science and Technology.) The primary goal of these new experimental programs is to develop methods to probe the very limits of atomic and molecular extent and temporal behavior. The diagnostics work mainly emphasizes development of high-precision spectroscopic probes to characterize the course of reaction in etching and film growth and to evaluate thin film structures. Such knowledge is vital to the successful application and optimization of industrial processes, particularly as critical dimensions shrink and demands for device performance and reliability become more stringent.

The subpanel believes that the materials research program uses JILA 's strengths to build what will become a center of excellence in optical characterization of solids. The knowledge and experience gained are important resources for discovery of new physical phenomena in the condensed phase and for techniques of direct technological interest to industry. The success of the effort depends on close partnerships between groups with optics expertise and groups that can

Suggested Citation:"5 Physics Laboratory." National Research Council. 1998. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories, Fiscal Year 1998. Washington, DC: The National Academies Press. doi: 10.17226/9515.
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produce and characterize the necessary samples. The JILA Fellows have worked to develop these partnerships, and the subpanel encourages them to continue to do so within NIST and the University of Colorado as well as with scientists at other institutions. Connections to complementary expertise are important in ensuring rapid progress in the experimental work and timely transfer of new insights into device design and process engineering.

Atomic and Molecular Interactions and Chemical Physics. The group working in atomic and molecular interactions and in chemical physics uses lasers to examine the structure and dynamics of atoms, molecules, ions, radicals, and clusters in carefully designed and unique, well-specified situations. The goals of these experiments are invariably to answer basic questions or to demonstrate the ability to exert microscopic control over intramolecular dynamics of a type qualitatively different from what has been feasible, understood, or even imaginable before. Several examples illustrate the breadth of the effort. First, new control schemes, based on crafting the amplitudes and phases of the spectral content of a femtosecond pulse, are being tested on the Li2 molecule for eventual use on more complex systems. Second, femtosecond pump-probe studies examine the detailed mechanism of solvation and caging, particularly the role of charge localization and delocalization in directing the dynamics of the solvent cage, in clusters of I2(CO2)n and I2(OCS)n. Third, a new pulsed discharge slit jet provides the best and most versatile known source for spectroscopic study of radicals, ions, and clusters. Some characteristics that make this jet so impressive are its high density, minimal collisions between reactive target species, low temperature, and long path length. Finally, pioneering work continues to explore “spectroscopy along the reaction coordinate, ” which is perhaps the most exciting incarnation of photodetachment spectroscopy, a technique whose birth coincided with that of JILA. Throughout the work in this field, each project combines, at the state of the art, at least two of the five goals stated in the Quantum Physics Division mission by developing the laser as a precise measurement tool and devising new ways to direct and control atoms and molecules.

Astrophysics. There are currently eight Astrophysics Fellows at JILA, and a few adjunct Fellows are still active in this field. In recent years, the JILA goals have largely turned away from the historical mission to perform laboratory astrophysics, although the JILA Astrophysics Fellows still retain strong intellectual ties to JILA Fellows in the NIST Quantum Physics Division and in the University of Colorado physics and chemistry departments. Many scientists in JILA view this interaction as stimulating and valuable. NIST no longer supports the Astrophysics Fellows, and thus they are primarily affiliated with the University's Department of Astrophysical and Planetary Sciences. They do, however, share JILA office space and infrastructure. This arrangement, although perhaps not optimal in the long run, is currently working quite satisfactorily. The Astrophysics Group makes up a sizable fraction of JILA Fellows (8 out of 21) and brings substantial overhead through research grants.

JILA Fellows working in astrophysics are likely to be known within their community as individuals rather than as members of a larger JILA team. In fact, many scientists in the astrophysical community are not even aware that JILA also houses research chemists and physicists. Scientific research published by JILA Astrophysics Fellows is world class and highly regarded in the astrophysics community. The research appears in the most prestigious, peer-reviewed journals and spans a wide range of topics, from complex numerical simulations and theoretical modeling of magnetohydrodynamic processes in the Sun and in interstellar space to

Suggested Citation:"5 Physics Laboratory." National Research Council. 1998. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories, Fiscal Year 1998. Washington, DC: The National Academies Press. doi: 10.17226/9515.
×

detailed modeling of supernovae and energetic compact objects. For example, research by astrophysicists at JILA led to a detailed seismological probing of the interior structure of the Sun. JILA scientists are also engaged in pursuing basic questions in cosmology, through studies ranging from surveying distortions in large-scale red-shift surveys of galaxies to measuring actual fossil relics of the nucleosynthesis processes that occurred in the first few minutes of the life of the universe. Astrophysicists at JILA are aggressive and successful participants in instrumentation missions for NASA, including the Goddard high-resolution spectrometer (GHRS) and the space telescope imaging spectrograph for the Hubble Space Telescope (HST). They are also involved with instruments for other upcoming NASA missions such as the Far Ultraviolet Spectroscopic Explorer, the Advanced X-ray Astrophysics Facility, and the Cosmic Origins Spectrograph.

JILA astrophysicists are also involved in the design of both ground-based and space-based interferometers for the detection of gravity waves and other space-based interferometers for the detection of Earth-like planets around other stars. Such projects define some of the cutting edges of astrophysics research. Many of these pursuits push the limits of dimensional stability and time referencing and, not surprisingly, flourish in JILA's historical atmosphere of state-of-the-art measurement.

The JILA environment seems quite conducive to the types of astrophysics research described above. One of many examples of the impact of the astrophysics work at JILA is the contribution made to determining whether there is sufficient matter in the universe to halt its expansion. This issue is one of the fundamental questions of modern cosmology. Because there are reliable theoretical models of the first few moments of the creation of the universe and laboratory measurements of the important atomic interactions, the application of the standard model of Big Bang nucleosynthesis predicts a deuterium to hydrogen ratio (D/H) of about 1:20,000, a ratio that is a relic of the moment of creation. A simple measurement of the primordial D/H ratio (the relative areas under two lines in a spectrum) provides a direct answer to the question of whether there is enough matter to halt the cosmic expansion. A JILA Fellow and his coworkers recently obtained D/H measurements in the local interstellar medium using the GHRS that JILA staff helped build for the HST. Taken together with other observations, these measurements will accurately trace the origin and evolution of the deuterium in the universe and thus yield the present-day density of baryonic matter. The JILA group on this project, because of its many years of development of the instrumentation and techniques for making these difficult measurements, is a key contributor to this important work. It is excellent science, of which JILA should be duly proud.

Impact of Programs

The JILA programs are actively and effectively disseminated through technical publications, invited talks, and the guest researcher program. During 1996 and 1997, 392 technical papers were published, permanent and visiting JILA staff members gave 243 invited talks, and 43 guest researchers worked at JILA. An especially noteworthy example of the impact of the scientific work at JILA has been the creation of eight BEC laboratories around the world subsequent to the pioneering, successful BEC work done at JILA.

The work to foster industrial connections at JILA is energetic and successful. A member of the staff reserves one-half of his time for coordinating industrial activities, and JILA is

Suggested Citation:"5 Physics Laboratory." National Research Council. 1998. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories, Fiscal Year 1998. Washington, DC: The National Academies Press. doi: 10.17226/9515.
×

aggressively pursuing three initiatives to improve its involvement with industry: an industrial outreach program, the expansion of JILA 's CRADA activities, and active efforts to identify and protect JILA 's commercially valuable intellectual property and to facilitate licensing by industry. The outreach program has brought in 9 or 10 visitors from industry per year to give a talk related to industry and science and to interact with graduate students, postdoctoral researchers, and staff members. The students view this program very positively. In addition, the “Industry at JILA” program brings senior engineers and researchers from industry to JILA for 1- to 2-week visits. There are currently five CRADAs in place that provide tangible connections to industry. Over the last several years, three U.S. patents have been granted and seven more have been filed in order to protect JILA's commercializable intellectual property. A very professional site on the World Wide Web makes it easy for interested companies to learn about JILA and make inquiries. The site is an effective means of disseminating information about the intellectual property available at JILA. Since 1994, about 26 graduate or postdoctoral students from JILA have taken jobs in industry.

Resources

Funding sources for the NIST Quantum Physics Division (in millions of dollars) are as follows:

 

Fiscal Year 1997

Fiscal Year 1998 (estimated)

NIST-STRS, excluding Competence

3.7

3.6

Competence

0.3

0.3

ATP

0.0

0.2

OA/NFG/CRADA

0.5

0.6

Other Reimbursable

1.1

1.1

Total

5.6

5.8

The University of Colorado contributes roughly $4.6 million, the National Science Foundation (NSF) contributes approximately $3.7 million, and other grants and visitor contributions total $4.5 million. This brings the total funding for JILA to approximately $18.6 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 four nonpermanent and supplemental personnel, such as postdoctoral fellows and part-time workers. Among the University of Colorado staff, there are 14 technical professionals.

Subpanel members met with groups of graduate students, research associates (mostly postdoctoral fellows), and technical and administrative staff. All spoke freely. High morale and the belief that JILA is a very good place to work were apparent in all three groups. The students and postdoctoral researchers have great respect and appreciation for the technical support, especially the electronic and machine shops, and the staff take pride in supporting world-class

Suggested Citation:"5 Physics Laboratory." National Research Council. 1998. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories, Fiscal Year 1998. Washington, DC: The National Academies Press. doi: 10.17226/9515.
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research and in helping students as well as Fellows. Shop staff will work unbilled overtime to complete jobs, and they feel free to initiate design suggestions. Students experience a sense of camaraderie and cooperation. Students feel that working “surprisingly” hard is the standard, and they believe that the Fellows work equally hard. Both the students and postdoctoral researchers are aware that they face a job market that has been tough in recent years, but they believe that JILA' s program to bring in speakers from industry and promote industrial connections serves them well. JILA's reputation is important in attracting postdoctoral workers but did not seem to have an effect on the graduate students.

An issue raised by postdoctoral workers in astrophysics illustrates the divergence between the patterns in JILA and those that best serve training in astrophysics. The postdoctoral workers had three specific concerns: that the computing support is costly and not particularly helpful; that obtaining clearance for proposals for observation time takes 2 weeks at JILA whereas it takes less than 1 hour at the Center for Astrophysics and Space Astronomy, another University of Colorado astronomy organization; and that postdoctoral researchers are discouraged from teaching because the pay increment is low ($1,000) despite the fact that teaching experience is very important for astronomers. The realignment of the astrophysicists with the University of Colorado over the next several years may well address these issues.

The subpanel sees the allocation and use of resources as key issues affecting the health of JILA and the determination of the directions in which the institute will develop. JILA is at a crucial transition point with decisions imminent in several important areas: the renewal of the staff, the creation of new programs, and the realignment of existing efforts. The planning associated with each of these changes is essential, and the resources required include, but are not limited to, funding. Any assessment of the adequacy of resources by the subpanel is intimately tied to future plans, and any planning must include a realistic consideration of the resources. The subpanel cannot make detailed observations about resource levels but does wish to outline some essential planning issues that are coupled to the decisions about resource requests and allocations.

JILA stands today at the edge of an exciting new era. Its scientific achievements over the past few years are outstanding, and NIST management has recently indicated the prospects of good support for the institute. Nevertheless, over the next few years several JILA Fellows are likely to retire and the astrophysics subgroup may be separating from JILA. These two major changes would provide the institute with an unusual opportunity to shape the future course of its activities and, given its influence in the scientific community, to shape the future course of atomic and molecular physics. The decision by NIST some years ago to focus support on JILA activities outside of astrophysics plus the need for the University of Colorado astrophysics community to have its own central base appear to be the core forces driving the JILA Astrophysics Fellows to seek a separate identity. The good will and rationality that have characterized the process to this point are impressive. Planning for the future is critical and the subpanel hopes that it will proceed in the same spirit of good will and fellowship.

An important first step is for the University of Colorado and NIST to reach a firm agreement about the number of JILA Fellows to be associated with the institute in the postastrophysics era. Numbers suggested during the subpanel's visit were 11 Fellows supported from University of Colorado funds and 11 from NIST funds. These numbers seem appropriate, and the subpanel expects that agreements about this issue will be solidified. Although it is logical that all of the Fellows will be in areas other than astrophysics, appointments are among the most precious of resources in a university. Thus, being certain that the new appointments will actually

Suggested Citation:"5 Physics Laboratory." National Research Council. 1998. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories, Fiscal Year 1998. Washington, DC: The National Academies Press. doi: 10.17226/9515.
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be administratively within the new JILA and that the astrophysicists are comfortable with this arrangement is essential.

A number of resource issues remain to be resolved. JILA management indicated that these issues pose no serious problems, and the subpanel is hopeful that at the next assessment it will hear about formal resolutions of these issues. For example, no space currently exists in which to house the entire astrophysics community at the University of Colorado. Therefore, the present Astrophysics Fellows are likely to remain within the JILA building complex for perhaps as many as 10 years. Several questions arise in this situation. Will there be sufficient space in the complex for new Fellows and how will support for the building complex be divided during this period? How will resources such as computer facilities, electronics, and machine shops be supported and managed during the transition period? Among the few complaints heard by the subpanel during its visit was some criticism by postdoctoral fellows in astrophysics regarding computer facilities. How much weight should be given to such concerns given the possibility of separation? Is there sufficient grant and contract support to maintain the high quality of the shops if the astrophysicists are not part of JILA?

Decisions regarding new appointments are among the most important and difficult to be made in shaping the future activities of the institute. The subpanel was not clear about whether the astrophysics subgroup will still be involved in appointment decisions about new Fellows during the upcoming transitional period. Assuming the astrophysicists remain as JILA Fellows during most of the transition, their influence in determining the new directions of JILA might be considerable. Yet such a course seems illogical in light of their eventual separation from the institute. It would be more appropriate for the core remaining JILA Fellows to be charged with the responsibility and the opportunity to determine the direction of the institute.

Finally, given the large number of potential new appointments of JILA Fellows, occasioned by retirement and new NIST and university commitments potential, it is critical to have a carefully developed plan for hiring. The subpanel estimates that in 5 years as many as one-half of the JILA Fellows could be new additions, depending on the rate of retirements and the commitment of both the university and NIST to new appointments. If the new appointments are delayed too long, the present positive atmosphere that favors them is likely to disappear. If the appointments are rushed, considerable strain will be placed on JILA's resources. For example, the subpanel sees the precision measurement and metrology effort as essential to JILA 's work and vitally connected to the NIST mission. However, identifying and making the appropriate additions to sustain that area may be a long and difficult process. Without a clearly articulated hiring plan, which surely will require significant discussions among the Fellows regarding future scientific directions, pressures to act quickly can lead to weak appointments and pressures to delay can allow crucial opportunities to pass. Either negative result would be tragic for an institute that has reached such a high level of success.

In summary of the above discussion, the decision to separate the astrophysics work from the remainder of the activities at JILA is supported by the subpanel. This process will be long and complicated, and according to the subpanel, there are five issues that are critical for JILA to consider as a transition plan is formulated: a clear commitment regarding the number of JILA Fellows from the University of Colorado and from NIST in the postastrophysics era; a clear plan and time line for hiring, including who will make the hiring decisions; a clear plan and time line for space utilization and availability and a clear plan and time line for eventual moves; a financial impact statement regarding the changes that will occur when the astrophysics subgroup leaves and

Suggested Citation:"5 Physics Laboratory." National Research Council. 1998. An Assessment of the National Institute of Standards and Technology Measurement and Standards Laboratories, Fiscal Year 1998. Washington, DC: The National Academies Press. doi: 10.17226/9515.
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how the departure will affect the JILA operations; and a realistic estimate of retirements and plans for replacements.

Major Observations of the Subpanel

Major observations of the subpanel are presented below.

  • JILA is at a crucial moment of change. The confluence of retirements, new research directions, and the decision that the astrophysics component will leave JILA brings the institute to a transition point. Management of this transition will require careful planning, obtaining the proper support from NIST and the University of Colorado, and vigilant implementation of the plan.

  • Precision measurement and metrology are at the heart of JILA and its success. Renewing the institute in a way that allows it to maintain its preeminence in these areas is essential. The subpanel is convinced that efforts in these fields have enlivened the science at JILA and allowed the institute to obtain the respect and support that it enjoys in the scientific community.

  • JILA has added excellent junior (Fellow-track) staff in the last 2 years. In the next few years, further additions of young staff who complement existing expertise and can carry JILA in newly defined directions are crucial.

  • Now is the time to define the JILA of the future through careful discussion and planning. The institute has already taken an important step by deciding on a future in which the astrophysicists are no longer associated with JILA. Now the institute is faced with the challenge of obtaining the support necessary to implement this transition. Successful change is possible only if NIST and the University of Colorado are willing to provide the proper institutional backing. From the NIST viewpoint, the proposal to reshape JILA without an astrophysics component by adding two NIST Fellows and two University Fellows is sound. Retiring Fellows must also be replaced for JILA to maintain an appropriate size. Management of these hiring activities will require considerable work by the Fellows and others.

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