Summary

At the request of the Director of the National Institute of Standards and Technology (NIST), in 2020 the National Academies of Sciences, Engineering, and Medicine formed the Panel on Assessment of Selected Divisions of the Physical Measurement Laboratory at the National Institute of Standards and Technology and established the following statement of task for the panel:

The Director of NIST requested that the panel consider during its assessment the following factors:

1. The technical merit of the current laboratory program relative to current state-of-the-art programs worldwide;
2. The portfolio of scientific expertise as it supports the ability of the organization to achieve its stated objectives;
3. The adequacy of the laboratory budget, facilities, equipment, and human resources, as they affect the quality of the laboratory’s technical programs; and
4. The effectiveness by which the laboratory disseminates its program outputs.

To accomplish the assessment, the National Academies assembled a panel of 24 volunteers whose expertise matched that of the work performed by the Physical Measurement Laboratory (PML) staff.¹ On May 17-20. 2021, the panel conducted a virtual review (via Internet media), a restriction imposed by the risks associated with the COVID-19 virus pandemic. During a plenary session, the panel received overview presentations by the acting NIST Director and the Director of the PML. Subsequently, the panel spent approximately 1.5 days receiving presentations from and engaging in discussions with the staff at the five divisions reviewed. On the third day, the panel met in a closed session to deliberate on its findings and to define the contents of this assessment report. The panel met with NIST management on the fourth day to clarify open questions. The choice of projects to be reviewed was made by the PML. The panel applied a largely qualitative approach to the assessment. Given the nonexhaustive nature of the

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¹ See the NIST Physical Measurement Laboratory at https://www.nist.gov/pmlfor information on PML organization and programs.

review, the omission in this report of any particular PML project should not be interpreted as a negative reflection on the omitted project.

TECHNICAL QUALITY OF THE WORK

The Quantum Measurement Division has six groups, each with significant accomplishments. These include single-photon sources (sources that produce streams of single photons) and detectors, quantum optics using laser cooling, the redefinition of the kilogram, and a graphene-based Quantum Hall Resistance Standard. Other notable achievements include the development of a Josephson-junction–based waveform synthesizer for power and energy applications, a unique magnetic suspension mass comparator, and the investigation of photon momentum for laser power and force measurements. Some of the best technical programs in the world are located in this division.

The Radiation Physics Division provides a unique resource to the United States, serving industrial, medical, and national security needs through its three groups. Its new gamma-radiation dosimetry calibration facility, detector calibration, and brachytherapy source traceability have produced improved calibration capability. The neutron physics program provides unique capability in the United States and is on par with the best neutron facilities worldwide. The neutron/X-ray tomography imaging facility offers the best simultaneous imaging available. The division has also developed a unique photon-assisted neutron detector for fast-neutron dosimetry. The division’s excellent technical capability provides outstanding service to the nation developing important new radiation detection and calibration methods.

The Microsystems and Nanotechnology Division is focused on advancing nanofabrication tools, technologies, and measurement systems. The three division groups work together to improve uncertainty in International System of Units (SI)-traceable calibration, fabricate devices such as accelerometers and atomic clocks, and develop nano-fluidics for biomedical applications. The study of the fundamental interactions of photons and phonons in nanostructures enables new tools while nonlinear optics enables new optical applications.

The Nanoscale Device Characterization Division is organized into five groups whose goals are to transform nano-scale and atom-scale technologies, engineered materials, and solid-state devices. The division’s strategic areas of research are as follows: theory and measurements for alternative computing; microscopies for quantifying emergent properties in quantum materials and devices; advanced microelectronics integration, characterization, and authentication; and atom-scale solid-state device theory, fabrication, and measurements. The quality of the division’s work is excellent as judged by the significant number of peer-reviewed publications and conference presentations.

The Sensor Science Division has responsibility for three of the seven base units of the International System of Units: the meter, the kelvin, and the candela. Its seven groups are aligned to support this significant assignment plus additional activities and programs. The technical quality of the division’s work is recognized worldwide through awards and commendations from multiple technical societies and organizations such as NASA and ASTM International (formerly the American Society for Testing and Materials). The division has an international reputation for technical excellence and is known and respected worldwide. It is highly involved in regional and international key comparisons that help to establish worldwide agreement on measurement standards.

TECHNICAL EXPERTISE OF THE STAFF

The technical expertise of the staff in the Quantum Measurement Division is outstanding and among the best in the world. Its research is at the forefront of the field in both theory and experiment.

The Radiation Physics Division has scientists and engineers with world-leading capability, high-impact publications, and strong international recognition, including American Physical Society (APS) fellows.

The Microsystems and Nanotechnology Division staff seem fully qualified to accomplish the various program goals.

The caliber and expertise of the senior researchers and associates in the Nanoscale Device Characterization Division is impressive. While the division staff are excellent device engineers and scientists, it would probably be helpful to add some systems design and engineering expertise to the team.

The highly respected technical expertise of the Sensor Science Division staff is the foundation for the division’s excellent international reputation. As an example, the International Organization for Standardization publishes the most important standard for calibration and test laboratories, the revision of this standard was co-convened by a division staff member.

ADEQUACY OF RESOURCES

The excellence of the staff and technical output at the PML has been maintained despite challenges that include, for some divisions, concerns about staffing shortages and the need for succession planning; and the need for facilities and equipment maintenance, upgrading, and replacement.

Two of the groups in the Quantum Measurement Division have been integrated with the Joint Quantum Institute (JQI) at the University of Maryland. This facilitates collaboration with other researchers and enables NIST researchers to have easier access to students. However, this has also led to the migration of much of the Quantum Optics and Laser Cooling and Trapping Groups from the NIST campus to the University of Maryland Campus, although efforts and collaborations remain on the NIST campus. This geographical separation is exacerbated by the loss of NSF funding for the Physics Frontier Center associated with the JQI, and by the deferred maintenance issues back at the NIST Gaithersburg site, both of which impact needed space expansion. HVAC and flooding issues at the aging Gaithersburg facilities have also impacted the division and its overall progress; this needs to be addressed.

The Radiation Physics Division has benefited from recent facility upgrades in their area, such as the Building 245 modernization project, the new high-dose-rate brachytherapy vault, and the future 10 MeV electron beam accelerator facility. There is concern, however, that maintaining this level of expertise may be difficult going forward, given the loss of senior staff and the competition for new hires. The recent loss of senior staff has led to more time spent on immediate needs than on long-term research for some senior staff, which may be counterproductive in the long term. It would be productive and cost effective to strengthen student and post-doctoral training to help mitigate this problem.

The Microsystems and Nanotechnology Division has extensive facilities, including two cleanrooms and a wide variety of fabrication and characterization tools. The PML maintains two fabrication facilities: one in Boulder and the other in Gaithersburg. The Microsystems and Nanotechnology Division has access to the Gaithersburg facility directly, and the Boulder one via collaboration. As with all such facilities, significant resources are required to keep the facility and tools at state-of-the-art levels.

The Nanoscale Device Characterization Division has excellent resources with outstanding equipment. The new photo emission microscope system and planned ultraviolet femtosecond light source will add to a well-equipped division.

Facilities available to support the Sensor Science Division are reported by staff to be inadequate to the task, and building renovations are planned to rectify this. However, the time scale for these fixes is such that aging infrastructure will severely limit for years the effectiveness of the division to achieve its goals and accomplish its mission of fostering the next generation of SI-traceable standards.

EFFECTIVENESS OF DISSEMINATION OF OUTPUTS

The Quantum Measurement Division has been highly effective in disseminating the results achieved in the division, notably including atomic spectroscopy data in the NIST Atomic Database,

publication in peer-reviewed journals and scientific conferences, and invited lectures explaining the new kilogram standards and the Quantum SI Revolution.

The Radiation Physics Division regularly publishes in top-tier peer-reviewed journals. The Neutron Physics Group sets an excellent example with strong collaborations, summer schools and workshops, and a high publication rate. Given the division’s technical accomplishments, more engagement with universities and professional societies may benefit the dissemination of the division’s output in some areas.

The Microsystems and Nanotechnology Division publishes extensively in both peer-reviewed journals and conference proceedings. In the previous 2 years, the division has published over 100 such articles. Collaborators include more than 40 top universities and research centers. The division staff are highly involved on conference committees, review panels, and standards bodies.

The Nanoscale Device Characterization Division is using not only traditional means of distribution for its outputs, it is also using new methods such as GitHub for making new software available to a wide audience. The division had over 100 publications and more than 130 conference presentations over the past 2 fiscal years, which indicates that other researchers are well aware of the progress being made in the division.

The Sensor Science Division is very effective at disseminating its results. The division staff publishes in high-impact journals and gives invited talks at key conferences around the world. Over the past 3 years, SSD staff published 240 archival journal papers, technical reports, conference proceedings, and book chapters. In addition, the division is proactive in organizing workshops and interlaboratory comparisons.

CROSSCUTTING CONCLUSIONS

The following conclusions apply to more than one group or program in the PML that was reviewed.

Technical Quality of the Work

The accomplishments of the PML’s staff are many and significant, spanning an extremely broad array of topics and including both research and support of the practical development of measurement standards. The staff innovatively develop and apply novel devices and techniques to solve important problems that affect industry, academic researchers, federal government agencies, and society in general. The work of the PML staff is effectively aligned with the NIST mission and is frequently performed in collaboration with researchers from those organizations.

The PML staff made commendable contributions during the COVID-19 pandemic. From March 2020, when staff were required to work remotely, PML staff ensured that essential services were performed for their customers, in support of national security, national well-being, and commerce. PML staff also answered the call to address measurement issues relating to combatting the virus, such as disinfecting agents and storage of vaccines.

Technical Expertise of the Staff

All the divisions of the PML have scientific and engineering staff with the appropriate level of expertise to deliver on their mission. In many cases, the staff are the best or among the best in their field of research. Staff have received numerous awards from professional organizations and from the Department of Commerce, which houses NIST.

The gender and minority employment gaps that are still strongly and broadly plaguing science, technology, engineering, and mathematics (STEM) fields remain an acknowledged, significant challenge

at NIST as well. The PML has implemented a plan to improve equity, diversity, and inclusion that involves the following features: monitoring promotion and salary data to ensure an equitable process; publishing promotion criteria so that staff know what is expected; mentoring by supervisors on how to advance; reviewing the pay level of all staff members with more than 8 years of service; participating in the APS’s Inclusion, Diversity, and Equity Alliance (APS-IDEA) in partnership with Howard University; sponsoring of and participating in conferences to increase women and minority participation in physics and other STEM fields; and supporting the PML Inclusivity Council, an internal grassroots organization working to identify barriers to inclusion and propose remedies. Addressing the challenge of staff attrition could provide opportunity to address diversity challenges as well. It is expected that in future years PML will demonstrate greater efforts and progress in diversity, equity, and inclusion.

Adequacy of Resources

Generally, but with significant exceptions, the PML staff are provided with adequate equipment and facilities to perform their tasks to a high degree of quality. Noteworthy exceptions include aging facilities in urgent need of upgrade, delayed maintenance on aging equipment, and an apparent lack of supercomputing support. All divisions reported concern about the adequacy of staffing levels, particularly given an aging workforce and severe competition for postdoctoral researchers and other new hires. Each division indicated initiation of strategic planning exercises with an eye toward addressing the current and predicted challenges associated with the limitations of equipment, facilities, and human resources.

Effectiveness of Dissemination of Outputs

PML staff are effectively disseminating the results of their work through appropriate means that include publication of research results; delivery of standard reference materials and standard reference data; performance of calibrations for industrial, academic, and government customers; participation on standards committees; sponsorship of workshops; and educational programs. Some customers, however, have complained about the amount of time it takes and the cost associated with purchased calibration services. They have also complained about the inadequate information provided by the web-based NIST Storefront interface for purchasing measurement services and about the lack of information about which services are currently available.