An Assessment of the National Institute of Standards and Technology Programs: Fiscal Year 1997 (1997)

John O. Dimmock, University of Alabama in Huntsville, Chair

Thomas M. Baer, Arcturus Engineering, Inc.

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

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

Kristl Hathaway, Office of Naval Research

Andrew Kaldor, Exxon Research & Development Laboratories

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, John O. Dimmock, this assessment of the fiscal year 1997 activities of the Physics Laboratory is based on site visits to the laboratory by the panel on February 4–5, 1997, and on the annual report of the laboratory.

The Physics Laboratory stated its mission as follows: The mission of the Physics Laboratory is to support U.S. industry by providing measurement services and research for electronic, optical, and radiation technology by pursuing directed research; developing new physical standards, measurement methods, and data; conducting an aggressive dissemination program; and collaborating with industry to apply NIST discoveries and commercialize NIST inventions.

The panel finds that this mission statement directly supports and is integrated into the NIST mission, because it focuses on providing basic measurements, metrology, and data for broad infrastructural support to industries in areas of basic physical science.

The Physics Laboratory conducts a broad, high-quality program of research and measurement services in support of U.S. industry and the scientific community. The laboratory is advancing metrological technology across the spectrum of its activities and improving delivery of this knowledge to the industrial and scientific communities. The breadth and power of the program is staggering, ranging from experiments dealing with fundamental issues in quantum physics to synchronization of traffic signals in Los Angeles. Projects reported in the press range from a demonstration and analysis of the fundamental physics of Bose-Einstein condensations and of the formation of optical lattices to the improvement of dose metrology in optical lithography, the development of a radiation standards facility for mammography calibration, and the demonstration of a high-accuracy cryogenic radiometer. Through the Fundamental Constants Data Center, a significant commitment has also been made to creating a centralized international source of information on the fundamental physical constants, closely related precision measurements, and the international system of units (SI). Furthermore, the Office of Electronic Commerce in Scientific and Engineering Data coordinates and facilitates dissemination of scientific and engineering data through electronic networks.

The work of the Physics Laboratory remains extremely effective and widely disseminated. The Physics Laboratory Technical Activities report lists more than 800 publications and 570 invited talks by the laboratory staff in 1995–96 and more than 370 examples of technical and professional committee participation and leadership.¹ The laboratory also sponsored 36 workshops, conferences, and symposia, and staff members edit 31 journals. With a total staff of about 206, this shows significant involvement and leadership in the scientific and technical community.

In addition, the Physics Laboratory has established, maintained, and issued 47 different Standard Reference Materials (SRMs) for calibration purposes and has supported or performed more than 1,600 calibration services during 1995–96. There is no question that the laboratory has a broad and important impact. It is also involved in and receives support for a significant amount of research and consulting for other agencies—further evidence of its effectiveness.

The Physics Laboratory has 37 Cooperative Research and Development Agreements (CRADAs) with industry and is participating in 27 additional industrial collaborative projects. These include CRADAs with such companies as IBM, General Electric, DuPont, W.R. Grace, Westinghouse, and Hewlett-Packard and reflect a significant increase in CRADAs since the panel's last report. It is clear that the laboratory has made strong industrial collaboration and interaction a priority and has been effective and successful in its efforts, which involve all six laboratory divisions. Each agreement or collaboration represents effective support for U.S. industry, because companies do not enter into these arrangements if they do not see significant return on their investment of time and resources.

Although there is no doubt that the laboratory has significant industrial impact, quantifying it is difficult. The laboratory has focused its efforts on establishing and carrying out collaborations rather than assessing their effects. (Two economic impact studies—on spectral irradiance and on optical detector calibrations—have been carried out, and there is an ongoing economic evaluation of the laboratory 's activities in ionizing radiation.) The effectiveness of the laboratory 's impact on industry is reflected in the repeat business it conducts with its industrial customers and in industry's commitment to continue to establish agreements and collaborations with the laboratory. Details of some specific industrial effects of the laboratory's work are found in the divisional reviews that follow.

Funding sources for the Physics Laboratory (in millions of dollars):

The staff of the laboratory includes 206 full-time permanent (FTP) positions, of which 159 are held by technical professionals, 148 of whom hold doctorates.

Funding for the laboratory has been level in constant dollars over the last 3 years, while the total professional scientific staff has been reduced by about 3 percent per year. The age distribution of the staff is reasonable and has remained roughly constant over the last 5 years. In general, the laboratory program is well balanced and highly productive. It continues to be at the forefront of science and metrology, adapting to and in many cases leading significant advances in this technology. Many of the ongoing programs in the Physics Laboratory deal with leading-edge technologies strategic to the U.S. position in the global marketplace. For example, the laboratory is active in microlithography essential to dense computer chip manufacture, in optics related to flat panel displays, in the use of ionizing radiation for cancer treatment and diagnosis, and in time synchronization essential to telecommunications. The laboratory often develops the science that is the basis of technologies. For example, its work on optical lattices and the properties of Bose-Einstein condensates are sure to find applications in future technology. The panel believes that the mission of the Physics Laboratory is growing in its importance to the scientific and industrial base of the United States. Strong support of this program to maintain or increase grow the current staff level is in the best interests of the country.

The Physics Laboratory has paid careful attention to the balance between OA and Scientific and Technical Research and Services (STRS) support. Although OA support is important, it is equally important that the laboratory have strong STRS funding to maintain its flexibility and mission focus. In recent years a conscious effort to increase the ratio of STRS to OA funding has had considerable success. The current ratio of STRS to OA funding appears appropriate, and the OA funding received is relevant to the laboratory's mission.

Though the overall laboratory equipment and facilities are good by most standards, facility limitations (and in some cases deterioration) are often hampering work and placing an undue burden on the research staff. In many areas only the inventiveness and dedication of the staff allow the laboratory to meet mission objectives in the absence of optimum or even adequate facilities. These are concerns about the age and technological obsolescence of buildings, safety, and growing maintenance costs. Major deficiencies include inadequate fume hoods, chemical storage, and exhaust systems; poor energy efficiency; frequent power outages and interruptions; insufficient chilled water capacity; lack of temperature, and humidity control; and substandard air cleanliness and vibration isolation. As the physical plant deteriorates, the technical requirements for higher accuracy and precision continue to increase, particularly in research and metrology for microstructures and atomic-scale structures, lasers and optical systems, complex electronic instrumentation, and computer networking. The quality of the laboratories and facilities required to carry out mission-relevant work has escalated rapidly as technology advances. Examples of the research and services most affected by facility inadequacies are given in the divisional reviews that follow.

The ongoing programs in the Physics Laboratory are generally well chosen and appropriate, indicating that there is good planning in the laboratory. However, the panel saw no evidence of a formal planning process, making the assessment of planning difficult.

The planning process of the Physics Laboratory appears to consist of two activities: development of specific initiatives for additional budget support and priority-setting. The former consists of Congressional Budget Initiatives submitted to Congress by the Institute, Competence Proposals submitted to the NIST Director by the laboratory director, and Director's Reserve Proposals submitted to the Physics Laboratory Director by division chiefs. Although this initiative process is common in government laboratories and the initiatives themselves all appear worthwhile, it is difficult to determine how effective it is for long-term program development. Much of this process does not appear to be driven as much by what interests customers as it is by how likely it is to obtain funding, at least with initiatives submitted to the level of NIST Director and above.

The laboratory's priority-setting process appears to be separate from the initiative process and not as well defined, or at least not as visible. The laboratory is currently updating its strategic plan, and an outline of that draft plan was provided to the panel by the laboratory. According to documents prepared for the panel, the strategic plan for the laboratory is a consensus document, formed from discussions between laboratory management and division chiefs. Its division components arise from similar discussions to reach consensus between staff and group leaders and between group leaders and division chiefs. The prioritization processes used by the different divisions within the Physics Laboratory are significantly different from each other. The divisions have quite varied programs and areas of responsibility and rather different missions and customers. It is therefore not unreasonable for them to use different priority-setting processes, but this makes assessing the overall laboratory prioritization processes difficult. Two established external technical advisory councils, the Council for Optical Radiation Measurements and Standards and the Council on Ionizing Radiation Measurements, make well-defined recommendations on program priorities for the laboratory divisions. In addition, the divisions receive feedback on their priorities from customer surveys and interactions, technology roadmaps, the NIST Visiting Committee on Advanced Technology, and through participation in technical and professional committees, workshops, industrial visits and program reviews, and scientific interactions and collaborations. Judging by the quality and technical content of the programs, this system must work. However, a better-defined process would make assessing the adequacy of plans more practicable for both this panel and NIST managers.

The Electron and Optical Physics Division stated its mission as follows: The mission of the Electron and Optical Physics Division is to develop measurement capabilities needed by emerging electronic and optical technologies, particularly those required for submicron fabrication and analysis.

The panel finds this mission to be in keeping with both the Physics Laboratory and NIST missions.

The technical merit of the division's work is of the highest level, in many instances constituting the premier effort in the world.

During 1996 the division's Photon Physics Group continued its activities in extreme ultraviolet (XUV) optics, optical standards for the XUV region of the spectrum, and XUV device development. This program builds on the group's extensive experience in vacuum ultraviolet (VUV) and XUV spectroscopy over the past decade. This group is also continuing its historical mission in VUV spectroscopy by attempting to measure the 1S-2S transition in helium using a Doppler-free two-photon technique. This experiment should give the highest precision measurement of the energy of this transition, which would allow for direct comparison with atomic theoretical calculations and challenge current approaches for predicting these transition energies.

The Synchrotron Ultraviolet Radiation Facility (SURF), overseen by the Far Ultraviolet Physics Group, remains the nation's primary standard radiometry source and serves a large and growing clientele in science and industry. This service will be expanded through an upgrade of SURF-II to SURF-III, which is currently under way. This upgrade will extend SURF's spectral range well into the XUV region, with the ultimate goal of making SURF-III the primary standard radiometry source from nanometer to millimeter wavelengths. Additional iron in the SURF-III magnet configuration and new copper coils will increase the electron energy from 284 MeV in SURF-II to about 400 MeV in SURF-III. This will effectively extend the usable photon energy into the soft x-ray range, enabling research in x-ray microscopy. Access to the “water window” photon energy range in SURF-III, between the carbon K-edge at 290 eV and the oxygen K-edge at 560 eV, will facilitate biological microscopy at the subcellular level and provide a tool for the study of carbon-based polymers superior to current methods. In the IR and far infrared (FIR) region of the spectrum, the superior brightness of the upgraded SURF storage ring will be used in a new IR/FIR spectromicroscopy facility.

The Electron Physics Group made a significant breakthrough in characterizing the interface alloy formed during growth at a hetero-epitaxial interface. For the first time, combining atomic-scale structural information from scanning tunneling microscopy with tunneling spectroscopy to identify the individual atoms through their electronic states gives a complete picture of the Fe/Cr interface, which is important in the production of magnetic structures exhibiting giant magnetoresistance (GMR). In a related theoretical project, first principles calculations of the spin-dependence of interface transmission and reflection coefficients of these and similar structures have shown that these effects are large enough to explain the observed GMR. The group's pioneering work on microfabrication by laser focusing has been replicated in materials other than chromium and has been extended from one-dimensional stripes to a two-dimensional matrix of dots 80 nm wide and 13 nm high.

The division meets the needs of its customers in the electronics and space industries through a mix of timely services and forward-looking development of advanced measurement and characterization techniques needed by industry.

Radiometric standards in the 4- to 250-nm spectral region are maintained. This region's importance is growing as the semiconductor industry moves toward higher packing densities, which demand lithographic technology employing sources in this spectral region. Upgrading the SURF will provide a well-characterized radiation source with calculable intensities over this spectral region and extending well into the FIR. This capability should prove invaluable for calibrating instruments for astronomical research and in commercial and military space applications.

Advanced micromagnetic characterizations that require the division 's unique Scanning Electron Microscopy with Polarization Analysis (SEMPA) facility are performed in house on magnetic storage industry samples to resolve important deficiencies and improve design in these devices.

The division has developed new x-ray optics coating technology that potentially allows measurement and correction of surface profile errors down to the level of a few nanometers. This technology is critical for U.S. competitiveness in the areas of photolithography and semiconductor manufacturing. The division plans to integrate component and coating technology into new x-ray microscope instruments. A version of this instrument will be suitable for imaging magnetic domains with a resolution of about 10 nm in magnetic recording materials. This capability is highly relevant to the magnetic recording and data storage industry. X-ray microscope technology may also be used to detect trace levels of biological molecules, which may find applications in forensics.

Each of the groups in the division maintains extensive contacts with industry. New capabilities developed in thin-film growth, characterization, and nanolithography will find quick application in the electronics industry.

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

Division personnel includes 27 FTP positions, including 20 technical professionals and 4 technicians.

New experimental capabilities (e.g., the Low Temperature Scanning Tunneling Microscope and SURF-III) proceeding on schedule will maintain the division's position at the forefront of experimental research.

This division has used substantial amounts of its funds to augment chilled water capacity, purchase uninterrupible power supplies, and improve humidity and vibration control where needed.

The division's research programs are appropriately chosen to have significant scientific opportunity, to optimize the use of division resources, and to provide the greatest impact for the division's customers.

The Atomic Physics Division stated its mission as follows: 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.

In the Atomic Spectroscopy Group, the installation and testing of a new Fourier transform spectrometer, with the best combination of wavelength range and resolution in the world (0.0025 cm⁻¹ over the range from 200 to 5500 nm), is nearly complete. A new data acquisition system is being developed and has been tested using various monochromatic sources. A molecular spectrum of water vapor has been obtained with a signal-to-noise ratio almost an order of magnitude better than the old system.

Close cooperation between experimentalists and theorists has led to significant achievements in understanding collisions in very cold gases of alkali atoms. The Quantum Processes Group includes theoreticians who are world leaders in researching cold atomic collisions and in developing sophisticated software for calculations in this field. The group has used the recently published ultracold photoassociation spectra of laser-excited sodium atoms obtained by the Laser Cooling and Trapping Group to extract basic data on long-range molecular potentials. This led to an indirect but extremely precise (within 0.1 percent) determination of the lifetime of the Na 3²P resonance level, correcting a significant systematic error in the best previous measurement. Theoretical calculations of the scattering length of one hyperfine structure state for cold ground-state Na atoms were compared with recent measurements of this parameter at the Massachusetts Institute of Technology and the University of Eindhoven, in the Netherlands. This information is important in understanding the role of collisions in Bose-Einstein condensates. A by-product of the analysis was the striking confirmation of retardation effects (due to the finite speed of light) on the structure of long-range molecular states. Additional theoretical analysis of collisions with Bose-Einstein condensates elucidated the potential role of collisional trap loss mechanisms in understanding the dynamics of such

condensates. The Bose-Einstein condensates are one possible means to overcome limitations that collisions would otherwise impose on the precision and accuracy of atomic fountain frequency standards, which are of great interest to the Time and Frequency Division of the Physics Laboratory.

The Laser Cooling and Trapping Group was also one of two groups in the world to experimentally demonstrate the Bragg scattering of light from an optically formed lattice of cold atoms levitated and bound together by standing-wave laser beams, rather than the interatomic forces that normally hold solids together.

An additional project of the Quantum Processes Group involves studies of the exciton states in quantum-wire lasers and of theoretical models of near-field scanning optical microscopy (NSOM). Related applied work in conjunction with the Optical Technology Division exploits analogous techniques for solving Schrödinger's equation in confined nanostructures and Maxwell's equations for near-field optics.

The Quantum Metrology Group (formerly the Quantum Metrology Division) has recently been incorporated into the Atomic Physics Division while retaining its name, personnel, and resources. The panel notes that this reorganization has been completed effectively. Although its resources (particularly in personnel) are limited, the group is a valuable and unique national resource, sought out by collaborators throughout the world because of the widely recognized outstanding technical merit of its work.

In October 1996, the group initiated a 5-year competence project with the Manufacturing Engineering Laboratory on Sub-Atomic Scale Displacement Metrology. This project is designed to develop competence at NIST to be able to directly validate the performance of ultrahigh accuracy interferometers for U.S. manufacturers. To continually improve the accuracy of length metrology at NIST, there is a long-term need for efforts such as this. Careful planning, including the appointment and training of scientific personnel, is required to address this need. A planning process for this area is now being discussed within the context of the new organizational structure of the Physics Laboratory.

The Quantum Processes Group performs state-of-the-art relativistic atomic structure calculations and develops computational techniques for calculating electron-impact photoionization cross-sections in molecules of technological importance for semiconductor plasma processing. The division has a CRADA with IBM in this field and has many other external customers for these calculations, both in industry and other government agencies.

This division is also responsible for three Atomic Data Centers: the Atomic Energy Levels Data Center, the Data Center on X-ray Transition Energies and Wavelengths, and the Data Center on Atomic Transition Probabilities and Line Shapes. These centers critically review, compile, and disseminate data on energy levels, wavelengths and line classifications, transition probabilities and oscillator strengths, and line shapes and radiative lifetimes for the spectra of atoms and atomic ions in all stages of ionization. This work is directly related to NIST 's basic mission. In addition to general purpose use in research, these data are used by the semiconductor industry, in industrial metrology, and in medical applications. The recent dissemination of these data in searchable form over the Internet greatly enhances their usefulness

to the community. In addition to these efforts, the division is sponsoring the First International Conference on Atomic and Molecular Data and Applications in the fall of 1997. A national search for a new hire to evaluate and compile atomic data is also under way.

The activities of the Quantum Metrology Group in x-ray sources and applications are highly appropriate to the mission of NIST, particularly regarding current and future uses for x-ray technology in science and industry. The industrial impact of this group is exemplified by the successful commercialization of its process for calibrating high-voltage x-ray mammography machines.

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

The division's personnel includes 31 FTP staff, including 20 technical professionals and 2 technicians.

Although the division's facilities (including physical plant) are generally adequate, certain groups face specific shortcomings in facilities and equipment that hamper their programs. Specific problems were found in the following areas: (1) Infrastructure: Power outages and voltage transients have caused equipment failures and loss of data. Poor drainage leads to occasional flooding and frequent high humidity. Quality and differential pressure capacity of cooling water result in marginal equipment operation and lost data. High particulate levels in the air damage optics, and the particulates are corrosive under humid conditions. Increases in noise and building vibration levels due to the development of and increased traffic in the community around NIST have made it more difficult to obtain precision measurements and reduced the quality of experimental data compared with that of a preoccupancy survey. The Laser Cooling and Trapping Group in particular has suffered from most of these infrastructure problems. The most disruptive are damage or dirt on optics due to poor air quality and condensation on water-cooled apparatus. To be able to conduct experiments, the group sometimes must hermetically seal equipment. These experiments are also particularly sensitive to laboratory temperature drifts, which cause misalignments and necessitate frequent readjustments. This group's laboratory and office space is also overcrowded. (2) Electron Beam Ion Trap (EBIT) and RF cell facility: Lack of adequate air conditioning and the laboratory's location adjacent to the loading dock cause dust problems with optics and excess vibration for the vacuum atomic force microscope associated with the EBIT. Power interruptions have caused damage to vacuum pumps and contamination of experiments with pump fluids, loss of vacuum, and quenching of the superconducting magnet during EBIT operation.

The panel did not discern adequate planning for anticipated retirement of critical scientific personnel, particularly in atomic spectroscopy, atomic data (including transition probabilities), and quantum metrology. As a result, there is concern about the future health of the Atomic Data program. Current trends in large-scale computer modeling suggest that the need for such data in industrial and scientific applications will increase greatly over the next few years. This is demonstrated by the number of inquiries the databases receive on the Internet: more than 20,000 inquiries per month. Some of the key people at NIST who do the critical data analyses are nearing retirement and are among the most respected members of this field internationally. A training program for the next generation would assure continuation of this valuable service. NIST is generally recognized as the world leader in this field. Continuity in highly complex databases and broad literature surveys is important, and it is highly unlikely that this work could be done by industry or academia. This area is not trendy enough to interest academic scientists and requires a long-term effort that cannot be easily delegated to their graduate students. Likewise, these efforts are for the long term, and their results are too broadly useful for any one industrial firm to benefit enough to undertake them.

The Optical Technology Division stated its mission as follows: The mission of the Optical Technology Division is, by advancing knowledge and expertise in targeted areas of optical technology, to provide the highest quality services, technical leadership, and measurement infrastructure to promote the U.S. economy and support the public welfare and the national defense.

The mission of the Optical Technology Division, while 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 temperature above the silver point). It develops radiometric, photometric, spectroscopic, and spectrophotometric calibration devices spanning a significant portion of the electromagnetic spectrum, from the microwave to the ultraviolet regions. The division provides standards and measurement quality assurance services to a wide customer base, including the lighting, photographic, automotive, and xerographic industries, as well as national needs in solar and environmental monitoring, health and safety, and defense. It increasingly performs state-of-the-art spectroscopic research and development that will provide new and improved standards, calibration services, and an ever-increasing database of optical and photochemical properties of materials. The mission of the Optical Technology Division, while broad, is central to the missions of both the Physics Laboratory and NIST.

The current division was formed in 1996 by the merger of most of the Molecular Physics and Radiometric Physics Divisions. (Some of the activities of these two former divisions were absorbed into others.) Despite the reorganization, the panel found the division's activities to be

well focused on its mission. The division is conducting significant research in optical sensor development, optical temperature and source calibration, molecular spectroscopy, laser applications, and measurement of optical properties of materials. Individual research groups are organized vertically, with the goals of advancing fundamental research in optical technology and developing new devices for the detection, measurement, and calibration of radiation across extensive wavelength ranges. There is significant tension between these two goals, which could lead the division to minimize basic research. Given the current research environment in U.S. industry, this is an important concern. However, the division can focus this tension creatively, using its leadership in technical fields to catalyze growth in industry while supporting its basic science components to enable future development of new technologies.

The responsibilities of the Optical Technology Division are exceedingly broad and diverse—ranging from basic research on applications of correlated quantum photon physics as absolute IR standards, to repeated and ongoing interactions with industrial-sector scientists and engineers to establish criteria for the color and appearance of common manufactured products. This diversity poses a challenge for the division as well as for the panel. This review will focus on selected technical sectors of the division's programs. In subsequent reviews, the panel will explore other aspects of their work and report on progress in other areas.

Although the three groups within the division with the word “optics” in their titles have specific and distinct responsibilities, the physics of light is common to them all. The Optical Temperature and Source Group is responsible for maintaining the national scales of radiation temperature, spectral radiance, and irradiance. The Optical Sensor Group focuses on the national measurement scale for the candela and research on detectors for radiometry, photometry, colorimetry, and spectrophotometry. The Optical Properties and Infrared Technology Group is concerned with standards of the measurement scales for the optical properties of real materials over the wavelength range from the deep UV (200 nm) to the far IR (30 µm). All of these groups conduct basic research related to their responsibilities and also provide measurement and calibration services and standard reference materials. It is clear that these groups interact successfully and often mount programs and outreach activities in concert with one another.

Work related to the national standards for radiometry and photometry is multifaceted yet shows a sensible balance between standard maintenance and basic research. The panel applauds development of detector-based standards, with the potential of higher accuracy and significantly reduced cost to both NIST and its customers. The success of these initiatives rests with the division's High Accuracy Cryogenic Radiometer. Research on the use of correlated photon physics as the foundation of another method of IR radiometry holds great promise for a future absolute standard. Ongoing efforts to support standards development at SURF III are essential to satisfy new and emerging industrial needs. One of many examples is the need for improved standards for UV radiation to meet the lithographic requirements for the next generations of semiconductor chips. The division has been called on to assist in the long-range and continuing support of the nation's earth-viewing satellite observations. This effort has successfully affected government programs in the National Aeronautics and Space Administration, the National

Oceanic and Atmospheric Administration (NOAA), the Naval Research Laboratory, the Environmental Protection Agency, the National Science Foundation, and the U.S. Department of Agriculture, and academic programs in oceanography at the Woods Hole Oceanographic Institute and the University of California, among others. The results of these environmental and remote-sensing programs critically depend on the radiometric and photometric calibrations and related technology provided by the division. Recent advances are communicated to such customers through technical notes and scientific publications and most recently through the Internet. Division staff have also hosted technical workshops and participated in the activities of technical and industry-based councils.

Division plans call for activities based on new scientific developments in metrology. Currently a program on near-field scanning optical microscopy (NSOM) is under development. In principle, materials and structures can be imaged to a resolution in the range of 20 to 100 nm using optical photons. The state of the art is young in this area, and the panel will track these activities with great expectations. The division has also been designing and developing new instrumentation for other government agencies. The extent of these activities speaks well for the quality of available instrumentation at NIST and the excellence of NIST personnel.

The Laser Applications Group develops and applies state-of-the-art, laser-based measurement techniques to characterize industrially and environmentally relevant processes. Staff emphasize strategic and interdisciplinary research in selected areas of photophysics, photochemistry, and optics. Their efforts include optical stimulation and characterization of transient processes in gases, liquids, and solids and at interfaces; linear and nonlinear light-scattering interactions as probes of surface and interfacial structure and dynamics; and measurements of nanometer-scale structures using optical techniques. Staff have numerous collaborations within NIST and extensive ties to researchers at universities, in industry, and at other government laboratories. The specific strengths of the group are discussed below.

Work in light scattering has made substantial progress in the analysis of the angular dependence and polarization properties of monochromatic light scattered from small particles and surfaces. Bidirectional Reflectance Distribution Functions derived from this work will substantially affect the development of production line diagnostics (SRMs, etc.) for surface roughness of silicon wafers and other applications. There are also interesting connections between this work and the technology of flat panel displays.

The group's new work in NSOM is exciting, both from the perspective of fundamental science and of emerging technologies. This cutting-edge area is likely to develop rapidly in the next few months. Imaging at a resolution of 1 nm should be possible in the near future. Additional resources will be needed to develop this area further, especially for bioscience and materials science applications.

Excellent progress is being made in the development of fast imaging technologies in the IR range. Chemical imaging is an important growth area, and this group is one of the leaders in the field. The work on interfaces in particular should be pursued. In addition, commercialization of the dual beam subpicosecond IR spectrometer should be investigated.

Equally exciting is work on fast laser probes of structure and dynamics at surfaces and in elementary chemical reactions. This work also has both fundamental and applied dimensions; the study of second-order nonlinear mixing in GaAs(001) reveals new features of the second harmonic generation process not recognized by others. The prospect of new technologies emerging from this work is high. Fast laser studies of the conformational dynamics of large

molecules (e.g., proteins) using the new THz light source are also an important opportunity for future growth.

The Spectroscopic Applications Group uses advanced spectroscopic measurement methods in the time and frequency domain as well as modern computational techniques to address fundamental and applied problems in molecular physics, chemistry, and related interdisciplinary areas. The group is making significant progress in the development of a Fourier transform microwave spectrometer for analytical applications. These applications are almost limitless. This method provides 100 percent species identification and has real-time monitoring capabilities and parts-per-billion detection limits. If the device is applied and commercially developed, the potential impact of this project is huge.

A compendium, “Molecular Microwave Transitions,” has been published and is available for use on the World Wide Web. Continued updating of these data and other related databases is necessary to retain their usefulness to industry, academia, and other national laboratories. Databases derived from the group's expertise in Fourier transform infrared (FTIR) spectroscopy would also attract a significant user group. New opportunities for metrology in THz technology also exist through collaboration with the Laser Applications Group.

The development of new theoretical models for the interpretation of the high-resolution MW and IR spectra of “floppy” molecules remains a healthy, active program. New spectroscopic databases and interactive computer programs for spectral analysis should emerge from this work.

Despite several recent staff retirements and relocations, the molecular spectroscopy laboratory is still a world-class facility whose advice and counsel is internationally sought and recognized. The panel applauds the hiring of two new staff members with PhDs to fill some of these vacated slots. These new hires will add vitality and energy to this group.

NIST could play a leading role in high-resolution optical (visible/UV) spectroscopy through creation of new databases, development of new interactive computer programs for the interpretation of spectra, and characterization of new materials in both the gas and the condensed phases. Other areas of emerging technologies include optical metrologies in biology (NSOM, etc.), nanoscale materials science, biomedicine, and magnetic resonance.

The panel commends the Optical Technology Division's continued efforts to improve the technology of detector-based radiometry. In combination with the upgrade of the SURF III facility, these efforts will provide a highly accurate system of measurement sources invaluable to American industry. The panel also commends the division for completing and implementing the Spectral Tri-function Automated Reference Reflectometer. This multiangle reference reflectometer system is unique among the national laboratories and essential to the development of color and appearance applications and SRMs.

The considerable industrial impact of this division will be further enhanced by its future plans:

• The continued development of a goniophotometry facility to allow measurement of radiant sources at multiple angles.

• The continued rewriting of the NIST 250 series of documents, which are invaluable to American industrial calibration laboratories. The impact of these documents would be increased if they were accessible on line.

• Further improvements in the speed of calibration services. Though the division reported a great improvement since the panel's previous assessment in 1995, the efficiency of turning over customer samples still lags behind similar services provided by other national laboratories.

• Working with constituent groups to assure SRMs are provided that suit the needs of American industry, and working with the NIST SRM office to assure that these materials are always available.

• Marketing the division, its services, and its products to more of the optical technology community throughout the world.

• Providing educational materials and services of its staff scientists to the optical technology community in the United States.

• Continuing to enhance the global harmonization of standards by increasing intercomparison studies with other national and industrial organizations.

ISO (International Organization for Standardization) Guide 25 outlines general requirements for the competence of calibration and testing laboratories. The guide mandates documentation of procedures for measurements and calibration techniques. The panel commends the division for being the first at NIST to embrace the ISO-25 guidelines. The division has completed the quality documents required under the guidelines and is revising the quality manuals to reflect changes in divisional structure. The initial ISO-25 division assessment has been completed by staff specially trained to be certified ISO assessors, and a second assessment is scheduled for the end of fiscal year 1997. ISO-9000, which covers management procedures and structures, has been deemed inapplicable to the division at this time.

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

Division personnel include 44 FTP staff, including 38 technical professionals and 1 technician.

The budget for the Optical Technology Division has remained relatively flat over several years. About 40 percent of the budget is OA support. This is appropriate given the large customer base (and diverse technology) served by this division. However, the current budget does not allow for the increasing need for the division's services. The division occupies space in four different buildings; this physical separation of staff diminishes the program's cohesiveness.

Considerable effort has been devoted to developing a strategic plan for the Optical Technology Division. This document appropriately summarizes the missions, goals, and objectives of each research group in a coherent and succinct way. The panel commends the division for this effort.

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

The Ionizing Radiation Division is recognized around the world as a leader in its field and addresses issues germane to the technology and industries within the scope of its charter.

In dosimetry, responding to concern expressed by the Council on Ionizing Radiation Measurements and Standards (CIRMS), the division collaborated with the Food and Drug Administration's Center for Devices and Radiological Health and the University of Wisconsin to develop a national reference air-kerma standard for mammography testing. This addressed a national need in an area of public concern and was duly noted in the laboratory director's testimony before Congress, with several congressional delegations visiting NIST to inspect the mammography standard facility. The division also developed dosimetry for the use of radioactive seeds to prevent restenosis and repair catheterized arteries after balloon angioplasty, an innovative use of radiolytic procedures in health care. The potentially widespread use of this technique makes this a topic of increasing importance. Although initial work concentrated on radioactive seeds, other active devices are being developed and will require similar consideration. Working relationships with industrial and academic research centers could help ensure NIST's leadership role in dosimetry for the innovative use of radiolytic procedures in health care.

In neutron research, the division demonstrated that sufficiently stable nuclear spin-polarized ³He could be produced for use in the magnetic resonance imaging of lungs. This

activity is an offshoot of basic neutron research in material science and physics, but the NIST effort could establish new and economical techniques for ³He production. The division also produced the first ever high-resolution use of neutron radiography with an interferometer to show the formation of hydrogen in a fuel cell, which is of critical interest to major corporations such as Exxon and Chrysler.

In radioactivity, the division developed radioactivity standards for ^117mSn, a promising bone palliation agent. It also completed construction of the Resonance Ionization Mass Spectrometer, which complements the division's analytical capabilities in low-level radioactivity measurements. The division is working with the American Association of Physicists in Medicine and CIRMS to move from an air-kerma calibration for radiation therapy energies to a water-based and possibly calorimetric calibration of absorbed dose. This is a major change in the physical basis of ionizing radiation standards and will have a substantial effect on radiation therapy dosimetry, especially if implemented through the accredited secondary standards laboratories. Examples of NIST contributions might include a set of standard measurement techniques for water media calibration using ionization chambers and dissemination of a detailed design for a suitable calorimeter, including performance standards for such a device.

Some divisional shortfalls stem from issues outside the division's control. For example, the division's Neutron Interactions and Dosimetry Group lost approximately $400,000 in transfer support from the Department of Energy, which curtailed some work in this area. Currently the group's short- and long-term goals (and the allocation of resources to pursue them) are not defined carefully enough. This is especially critical because the neutron dosimetry research, which is mostly associated with dosimetry needed for the fuel cycle, is staffed by retired staff or those nearing retirement. In another instance, failing to maintain or replace corroded hoods has slowed critical work on some environmental projects in the Radioactivity Group.

The effectiveness of the division's work is exemplary in the diverse constituencies it serves. These include the medical community, industrial radiation processing, the nuclear industry, and the growing use of radioactive tracers for environmental diagnostics as well as in issues related to health and safety of personnel. However, the division could more effectively disseminate its work.

Though the U.S. nuclear power industry is stagnant, nuclear power may become increasingly important over the next 10 years. NIST should ensure that it will be able to provide support to the fuel-cycle industry during such a transition.

With a staff of approximately 30 professionals, the division published 71 articles in scientific journals, issued 10 reports, and contributed to 27 conference proceedings in 1995–96. This indicates an average publication rate of about three papers per staff member during this period. Given the level of funding, this may seem somewhat sparse for certain research areas, especially the Neutron Interactions and Dosimetry Group. However, publication is slower during initial project phases, and a good deal of ongoing activity should result in a steady stream of publications in the years ahead.

The division also uses workshops and conference participation as a means to disseminate its work. By conducting workshops, the division brings together constituencies to focus on scientific and technical areas. These have proven beneficial to the participants, but their full impact has not yet been felt through the publication of the results of such meetings in scientific and technical journals. To ensure future support, the division needs to devote more attention to

seeking proper recognition for such activity among the broader scientific and technical communities.

Through its calibration services and provision of SRMs, the division supports of the historic NIST role in the standards arena. These areas are complemented by attention to ISO 9000 and Guide 25 implications for such standards issues, although the division laboratories are not seeking ISO certification. The division chief is taking a more active role in the international standards community, having been nominated for president of the International Committee for Radionuclide Metrology and becoming more active in the Consultative Committees of the International Bureau of Weights and Measures (BIPM). Through participation in the American Society for Testing and Materials (ASTM) Committee E-10 on dosimetry measurements, division members have helped in reconcile ASTM methods with American National Standards Institute (ANSI) and other U.S.-based organizations. But there are challenges still to be faced in dealing with the non-U.S.-based ISO and European Commission (EC) entities.

The division's attention to industrial impact is exemplified by its participation in the CIRMS and ASTM. Industry gives feedback through these organizations and through the division's involvement in CRADAs. CRADAs and other similar arrangements have existed in the division since the early 1970s in radioactivity standards, where several research associates are currently supported through such means. A CRADA is being negotiated with a trade organization for calibrations needed by the medical device sterilization industry. Another CRADA to implement development of film dosimeters based on alanine is stalled because of downsizing at the corporate partner. Given this technology's potential, the division should be able to quickly establish a new partnership as a viable commercial source for these materials.

In dosimetry, the division is widely recognized within industry for its expertise. The Physics Laboratory is sponsoring a study to be conducted by the University of North Carolina, Greensboro, to better define the economic impact of division activities. The division' s estimates of the dollar value of the businesses it serves are significantly below what other industry experts would have projected.

Although the division wants to interact with other laboratories at NIST, some opportunities are missed because interlaboratory programs are not more common. For example, NIST's expertise in manufacturing disciplines has not integrated the use of ionizing radiation, with its environmental and economic benefits, into development of innovative processes based on known radiation responses.

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

The division has 37 FTP staff, of whom 28 are technical professionals and 3 are technicians.

The age profile within the division has been adjusted in the last several years as younger personnel have been brought into replace retiring senior staff. The staff member most expert in theory has assumed managerial responsibilities. A strong theoretical and computational capability is important; given the breadth of the division's activities from basic to applied efforts, such expertise affects all projects. The absence of this expertise is a significant shortcoming. Previous panel reports suggested that this be addressed by recruiting from the pool of young scientists at NIST or at collaborating institutions. This will work only if implemented in the next few years, as the transfer of information and techniques and the requisite one-on-one training can only occur while soon-to-be-retired senior personnel are still available. A midcareer individual in theoretical radiological physics, with special expertise in radiation transport, could provide immediate support in this area. This division also lacks sufficient expertise in computational methods.

The division has done an astute job of managing its resources in times of fiscal restraint. However, it needs to have stronger external support and to participate in the deliberations of other federal departments and agencies as they allocate resources including personnel, programs, equipment, and funding related to ionizing radiation. Some of the division's goals and objectives (and those of the ionizing radiation community in general) could benefit from more coordination in this area among all parties. This is a field in which the division could provide national leadership.

The Ionizing Radiation Division has unique capital requirements. Unlike most laboratories within NIST, individual capital demands in the field of ionizing radiation often require expenditures of at least several hundred thousand dollars. Though the division has addressed a number of concerns regarding its MIRF facility (Medical-Industrial Radiation Facility), the lack of a 6- to 8-MeV accelerator precludes direct comparison with accelerators currently used in the medical community. Likewise, the industrial use of scanned, high-current electron beams will require modification of current equipment or acquisition of new equipment to adequately serve the industrial electron-beam processing community. There is enough space and shielding thickness within the vaults of the Radiation Physics Building to accommodate additional equipment. Some facilities problems, such as inadequate cooling water to operate the MIRF, can be overcome with a modest purchase of ancillary cooling systems. As with all of the

other buildings in the NIST complex, the Radiation Physics Building suffers from antiquated air systems that spreads particles throughout the building. Particulates in air can affect the precision of some dosimetry measurements. The existing facilities are essentially quite usable if a few minor problems causing specific difficulties are corrected, but the problems noted directly affect the division's ability to accomplish its mission.

A clear, succinct statement of the mission of the Ionizing Radiation Division was provided that also enumerated the division's vision, values, objectives, and strategic goals and cited the principal technical directions for each of the division's three groups—the Radiation Interactions and Dosimetry Group, the Radioactivity Group, and the Neutron Interactions and Dosimetry Group. A list of tactical goals or objectives was provided along with one highlighting future/potential technical opportunities. Appended to this was a summary table categorizing each group's strategic goal and tactical goals or major objectives for fiscal year 1997 as they relate to industry needs.

Division management strives to keep each group focused on at most four major technical issues and is attentive to budgetary and personnel constraints. Within this diverse array of programs, there are responses to crucial industry issues as well as surprisingly innovative initiatives, not programmed into the division's objectives for fiscal year 1997, such as the use of fullerenes to transport radioactive isotopes for diagnostic purposes.

The division has done an excellent job in responding to the items cited in the CIRMS document, Report on National Needs in Ionizing Radiation Measurements.² By being an active participant in CIRMS, the division is kept apprised of the evolution of this document and can plan for future activities projected by CIRMS in a forthcoming revision (due out in January 1998) of its needs report. The division also receives input from other bodies such as ASTM and its committees, the Nuclear Regulatory Commission, and the National Council on Radiation Protection, which help formulate future efforts. Its continued participation in the International Meetings on Radiation Processing will help the division expand and sustain its contact base.

Division planning is adequately integrated into planning for the Physics Laboratory as a whole.

The Time and Frequency Division stated its mission as follows: The mission of the Time and Frequency Division is to support U.S. industry and science by providing measurement services and research in time and frequency, and related technology.

The division's mission is well integrated into both the Physics Laboratory and NIST missions, and it currently works well with industry. The division makes an effort to understand what is and will be important to industry. It has strong interactions with industry through direct contacts as well as through participation in conferences and symposia. The division and its scientists are recognized nationally and internationally as leaders in frequency and time technology, related measurement technology, basic frequency standards, time scales, and dissemination of frequency and time measures. The division staff also participates actively in international standards organizations.

The division is probably the best in the world in the area of frequency and time. Not only does it currently have excellent working frequency standards with supporting technologies and dissemination methods, but it also has outstanding developments under way for next-generation needs. This work is increasingly important for industry because of the need for time synchronization in telecommunications, international frequency and time comparisons, and inputs to the International Atomic Time (TAI) scale. Commercial atomic frequency standard designs benefit from NIST work, are widely used in the national laboratories, and contribute to the TAI scale.

The performance of the optically pumped NIST7 cesium beam standard is outstanding. The accuracy evaluation is new at 5 × 10⁻¹⁵, with further improvement expected. This currently gives NIST the world's leading cesium beam standard and makes NIST one of the main contributors to the rate of TAI scale. This excellent performance is due not only to the optically pumped beam tube but also to the high-quality electronics design and execution. The division recently received $750,000 to make a copy of NIST7 for the Communications Research Laboratory in Japan.

The division is making progress on a cesium atomic fountain. This involves collaboration with the Atomic Physics Division on transverse cooling. Collaboration is also under way with the Politecnico De Torino, Italy, on design of a microwave cavity with low distributed phase shift. The LPTF/BNM Observatoire de Paris in France already has a fountain in operation, which places the division somewhat but not very far behind in this field. Future application of transverse cooling at the NIST fountain should provide a better signal-to-noise ratio than the French effort has achieved, an important advantage assuming the fountain's flywheel oscillator has low enough noise.

Work in trapped ion frequency standards using a linear string of cooled ¹⁹⁹Hg ions is without peer in both the microwave and optical regions. The potential accuracy is about 10⁻¹⁸; once again, an extremely good flywheel oscillator is crucial. Development of high-stability sapphire resonators and oscillators for use as flywheel oscillators in the advanced frequency standards could be enhanced through collaboration with groups active in the field at the Jet Propulsion Laboratory or the University of Western Australia. This type of oscillator could potentially solve part of the problem of realizing the frequency stability capability of the advanced standards.

In investigating the properties of correlated states in the ion string for noise reduction, it became possible to use the ion system for demonstration of a quantum logic gate, the basic

element of a quantum computer. The group demonstrated this successfully for the first time. Further work is proceeding. It is partially financed by the National Security Agency because of the potential advantages of quantum computation in solving special types of problems such as factorization of large integers.

The group is now leading the world in phase and amplitude noise studies and electronics for frequency standards and clocks. Excellent progress has been made in understanding flicker-of-phase noise and its reduction in amplifiers, essential for developing low noise oscillators. In addition, steady progress has been made in developing low noise synthesizer chains for frequency standards, with particular emphasis on frequency pulling effects. The group also performs many calibrations for industry.

The stability of the NIST Coordinated Universal Time (UTC) scale with respect to the UTC disseminated by BIPM has improved greatly over the last several years. Excursions of more than 100 nsec have been reduced since early 1996 to less than 20 nsec. Part of the improvement comes from learning how to use hydrogen masers better. Allowance for maser drift will be incorporated into the time scale.

The division's telephone service, which provides time synchronization to several milliseconds by modem, receives about 10,000 calls per day. Similar service on the Internet is logs 2 million hits per day.

The division was fortunate to receive three surplus transmitters from the Navy, which will be used to upgrade WWVB (the NIST low-frequency radio transmitter that broadcasts time signals from a Colorado location) to over 50,000 W. Some antenna modifications will also be made. These changes will improve WWVB's coverage of the United States and allow for automatic resetting of appropriately designed consumer appliances, including special watches and clocks, some of which are already on the market.

Special lasers are being developed within the division for its own use as well as for use elsewhere within NIST. Many of these lasers are narrow band, stabilized diode lasers used for optical pumping of several types of frequency standards. In collaboration with NOAA, some are used spectroscopically for atmospheric chemistry. They are also being used to develop swept frequency precision-length measurements.

The division has also started work on a Division Quality Manual to gain some consistency with ISO developments.

In view of the division's missions and those of NIST, the programs are appropriate and are being carried out quite effectively. The results appear in archival publications and other journals and are presented at conferences. Frequency and time are well disseminated through broadcasts, the Internet, and by telephone. The division is a major contributor to the international time scale and the determination of the SI unit of time.

Contributions to the international time scale, the definition of the second, techniques for time transfer and synchronization, and the dissemination of time and frequency are of immediate and growing importance in telecommunications. Calibrations are performed for industry by the division and are given priority according to the demand. The importance of continuing improvement in frequency standards is difficult to assess; but historically, the needs for

improved accuracy and stability have followed their development fairly closely. This work is clearly important from a scientific standpoint. Improvements in amplifier phase noise and circuit design have direct impact on the precision oscillator industry. The division's contributions to length metrology through swept laser frequency technology have a potentially significant impact.

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

The division has 42 FTP staff, including 33 technical professionals and 4 technicians.

Much of the work on basic standards is supported by other agencies, particularly the Department of Defense. The division receives funding from the Air Force and the Advanced Research Projects Agency for support of the Global Positioning System and related technology. Funding per project is decreasing in some areas, resulting in more total projects and less available staff time per project.

The technical capability of the staff is excellent. Several staff members have been offered extremely good positions elsewhere but have opted to remain at NIST. They appear pleased with the technical challenge offered by their work and satisfied with the available resources.

The division's physical plant is comparable to that of other laboratories doing similar work. It is for the most part adequate, but some vibration problems are associated with the local heating and air conditioning. These vibrations limit the performance of several systems that rely on extreme laser frequency stability.

The division has carried out long-range planning for many years. Recently the format of this planning exercise became more like that of a strategic plan. The planning process is significantly facilitated by the interdependence of the programs, which leads to much informal discussion among the staff and with the division chief. When the discussions result in a written plan, it is circulated and refined until there is virtual consensus. This process is effective. The staff appear satisfied with the direction the division is taking; the division is performing its tasks well; and it has the respect of industry, academia, and other laboratories.

• The Physics Laboratory is engaged in a broad array of high-quality programs, with applications from quantum physics to synchronization of urban traffic signals. Its Data Centers are directly related to the basic NIST mission to support science and industry users.

• The laboratory disseminates the results of its programs widely through publications, workshops, conferences, standards committees, and the Internet.

• The laboratory suffers from major facility deficiencies including inadequate fume hoods, chemical storage, and exhaust systems; poor energy efficiency; frequent power outages and interruptions; insufficient chilled water capacity; lack of temperature, air conditioning, and humidity controls; and substandard air cleanliness and vibration isolation. As the physical plant continues to deteriorate, the technical requirements for higher accuracy and precision are increasing, particularly in research and metrology for microstructures and atomic scale structures, lasers and optical systems, complex electronic instrumentation, and computer networking.

• The panel was presented with no plans to assure that existing facilities are optimally used across all NIST laboratories in the event construction of new facilities is delayed or canceled. Research projects with the most stringent facility requirements should be assured of being housed in the facilities that meet those requirements.

• Though the Physics Laboratory has an operative planning process, its diverse nature makes assessing its efficacy difficult. Clearly the laboratory is making considered decisions regarding what direction it should take. However, the laboratory would be better able to support its planning decisions and present them to others if the planning and decision-making processes were better defined.

• A training program for the next generation of researchers is lacking for the Atomic Database program. NIST is generally recognized as the world leader in this field. It is highly unlikely that this work could be done by industry or academia because of the continuity called for in complex databases and broad literature surveys.