AN ASSESSMENT OF THE 

NATIONAL INSTITUTE OF STANDARDS 

AND TECHNOLOGY 

PHYSICAL MEASUREMENT LABORATORY

FISCAL YEAR 2015

Panel on Review of the Physical Measurement Laboratory at the

National Institute of Standards and Technology 

Committee on NIST Technical Programs

Laboratory Assessments Board

Division on Engineering and Physical Sciences
THE NATIONAL ACADEMIES PRESS 500 Fifth Street, NW Washington, DC 20001

This study was supported by Contract No. SB1341-12-CQ-0036/15-034 with the National Institute of 

Standards and Technology. Any opinions, findings, conclusions, or recommendations expressed in this 

publication do not necessarily reflect the views of any organization or agency that provided support for the 

project.

International Standard Book Number-13: 978-0-309-43936-7

International Standard Book Number-10: 0-309-43936-1

Digital Object Identifier: 10.17226/23448

Copies of this report are available from

Laboratory Assessments Board

Division on Engineering and Physical Sciences

National Research Council

500 Fifth Street, NW, Keck 928

Washington, DC 20001

Additional copies of this report are available from the National Academies Press, 500 Fifth Street, NW, Keck 

360, Washington, DC 20001; (800) 624-6242 or (202) 334-3313; http://www.nap.edu.

Copyright 2016 by the National Academies of Sciences, Engineering, and Medicine. All rights reserved.

Printed in the United States of America

Suggested citation: National Academies of Sciences, Engineering, and Medicine. 2016. An Assessment of 

the National Institute of Standards and Technology Physical Measurement Laboratory: Fiscal Year 2015. 

Washington, DC: The National Academies Press. doi:10.17226/23448.
The National Academy of Sciences was established in 1863 by an Act of Congress, signed by 

President Lincoln, as a private, nongovernmental institution to advise the nation on issues 

related to science and technology. Members are elected by their peers for outstanding 

contributions to research. Dr. Ralph J. Cicerone is president.

The National Academy of Engineering was established in 1964 under the charter of the 

National Academy of Sciences to bring the practices of engineering to advising the nation. 

Members are elected by their peers for extraordinary contributions to engineering. Dr. C. D. 

Mote, Jr., is president.

The National Academy of Medicine (formerly the Institute of Medicine) was established in 

1970 under the charter of the National Academy of Sciences to advise the nation on medical 

and health issues. Members are elected by their peers for distinguished contributions to 

medicine and health. Dr. Victor J. Dzau is president.

The three Academies work together as the National Academies of Sciences, Engineering, 

and Medicine to provide independent, objective analysis and advice to the nation and 

conduct other activities to solve complex problems and inform public policy decisions. The 

Academies also encourage education and research, recognize outstanding contributions to 

knowledge, and increase public understanding in matters of science, engineering, and 

medicine. 

Learn more about the National Academies of Sciences, Engineering, and Medicine at 

www.national-academies.org.

v

PANEL ON REVIEW OF THE PHYSICAL MEASUREMENT LABORATORY AT THE 

NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY

ROBERT H. AUSTIN, Princeton University, Chair

SHELLEY L. ANNA, Carnegie Mellon University

GORDON D. CATES, Jr., University of Virginia

DONALD M. ENGELMAN, Yale University

MICHAEL ETTENBERG, Dolce Technologies

STEPHEN R. FORREST, University of Michigan

ROBERT P. FRUEHOLZ, The Aerospace Corporation

JAMES S. HARRIS, Stanford University

ALAN JOHNSTON, Measurement Canada

MLADEN KEZUNOVIC, Texas A&M University

STEVEN M. LARSON, Memorial Sloan-Kettering Cancer Center

JAMES E. LAWLER, University of Wisconsin, Madison

ATHANASIOS P. (SAKIS) MELIOPOULOS, Georgia Institute of Technology

PIERRE MEYSTRE, University of Arizona

C. KUMAR N. PATEL, Pranalytica, Incorporated

MARK G. RAIZEN, The University of Texas, Austin

R.G. HAMISH ROBERTSON, University of Washington

MARLAN O. SCULLY, Texas A&M University

ROBERT M. SHELBY, IBM Almaden Research Center

RICHARD SHIPMAN, Rice Lake Weighing Systems, Incorporated

JOHN C. SOMMERER, Talitha Ventures

MICHAEL G. SPENCER, Cornell University

DAVID A. THOMPSON, IBM Almaden Research Center

ANDREW M. WEINER, Purdue University

DAVID A. WEITZ, Harvard University

H. KUMAR WICKRAMASINGHE, University of California, Irvine

X. GEORGE XU, Rensselaer Polytechnic Institute

Staff

LIZA HAMILTON, Associate Program Officer

EVA LABRE, Administrative Coordinator

JAMES P. MCGEE, Director 

ANDREA SHELTON, Administrative Assistant (until December 24, 2015)
vi

COMMITTEE ON NIST TECHNICAL PROGRAMS

ELSA REICHMANIS, Georgia Institute of Technology, Chair

LEWIS BRANSCOMB, Harvard University

WILLIAM C. GEAR, NEC Research Institute, Inc. (retired)

JENNIE S. HWANG, H-Technologies Group

KANTI JAIN, University of Illinois, Urbana-Champaign

C. KUMAR PATEL, Pranalytica, Incorporated

ALICE WHITE, Boston University

Staff

LIZA HAMILTON, Associate Program Officer

EVA LABRE, Administrative Coordinator

JAMES P. MCGEE, Director 

ANDREA SHELTON, Administrative Assistant (until December 24, 2015)
vii

LABORATORY ASSESSMENTS BOARD

JOHN W. LYONS, National Defense University, Chair

ROSS B. COROTIS, University of Colorado, Boulder

PAUL A. FLEURY, Yale University

C. WILLIAM GEAR, Princeton University

WESLEY L. HARRIS, Massachusetts Institute of Technology

JENNIE S. HWANG, H-Technologies Group

W. CARL LINE BERGER, University of Colorado, Boulder

C. KUMAR N. PATEL, Pranalytica, Incorporated

ELSA REICHMANIS, Georgia Institute of Technology

LYLE H. SCHWARTZ, U.S. Air Force Office of Scientific Research (retired)

Staff

LIZA HAMILTON, Associate Program Officer

EVA LABRE, Administrative Coordinator

JAMES P. McGEE, Director 

ARUL MOZHI, Senior Program Officer

ANDREA SHELTON, Administrative Assistant (until December 24, 2015)

ix

Acknowledgment of Reviewers

This report has been reviewed in draft form by individuals chosen for their diverse perspectives 

and technical expertise, in accordance with procedures approved by the Report Review Committee. The 

purpose of this independent review is to provide candid and critical comments that will assist the 

institution in making its published report as sound as possible and to ensure that the report meets 

institutional standards for objectivity, evidence, and responsiveness to the study charge. The review 

comments and draft manuscript remain confidential to protect the integrity of the deliberative process. We 

wish to thank the following individuals for their review of this report:

Steven M. Girvin, Yale University,

Arthur C. Gossard, University of California, Santa Barbara,

Jerome Hastings, Stanford University,

Max G. Lagally, University of Wisconsin, Madison,

Daniel M. Stamper-Kurn, University of California, Berkeley,

Thomas P. Russell, University of Massachusetts, Amherst, and

Stephen R. Leone, University of California, Berkeley.

Although the reviewers listed above have provided many constructive comments and suggestions, 

they were not asked to endorse the conclusions or recommendations, nor did they see the final draft of the 

report before its release. The review of this report was overseen by Elsa Reichmanis, Georgia Institute of 

Technology, who was responsible for making certain that an independent examination of this report was 

carried out in accordance with institutional procedures and that all review comments were carefully 

considered. Responsibility for the final content of this report rests entirely with the authoring board and 

the institution.

xi

Contents

SUMMARY 1

1 THE CHARGE TO THE PANEL AND THE ASSESSMENT PROCESS 7

2 APPLIED PHYSICS AND QUANTUM ELECTROMAGNETICS DIVISIONS 9

3 ENGINEERING PHYSICS DIVISION 18

4 OFFICE OF WEIGHTS AND MEASURES 23

5 QUANTUM MEASUREMENT DIVISION 26

6 QUANTUM PHYSICS DIVISION 31

7 RADIATION PHYSICS DIVISION 36

8 SENSOR SCIENCE DIVISION 42

9 TIME AND FREQUENCY DIVISION 48

10 KEY SUGGESTIONS FOR IMPROVEMENT 56

ACRONYMS 59

1

Summary

In 2015, at the request of the Director of the National Institute of Standards and Technology 

(NIST), the National Research Council (NRC)1 formed the Panel on Review of the Physical Measurement

Laboratory at the National Institute of Standards and Technology (referred to in this report as “the panel”) 

and established the following statement of task for the panel:

The National Research Council shall appoint a panel to assess the scientific and technical work 

performed by the National Institute of Standards and Technology (NIST) Physical Measurement 

Laboratory (PML). This panel will review technical reports and technical program descriptions 

prepared by NIST staff and will visit the facilities at the Physical Measurement Laboratory. Visits 

will include technical presentations by NIST staff, demonstrations of NIST projects, tours of NIST 

facilities, and discussions with NIST staff. The panel will prepare a report summarizing its 

assessment findings.

NIST specified that the nine divisions of the PML would be reviewed: the Applied Physics 

Division (APD), Engineering Physics Division (EPD), Office of Weights and Measures (OWM), 

Quantum Electromagnetics Division (QED), Quantum Measurement Division (QMD), Quantum Physics 

Division (QPD), Radiation Physics Division (RPD), Sensor Science Division (SSD), and Time and 

Frequency Division (TFD).

GENERAL OBSERVATIONS

The PML remains an outstanding institution of the highest standards and accomplishments.

Broadly speaking, the PML is dedicated to three fundamental and complementary tasks: (1) increase the 

accuracy of our knowledge of the physical parameters that are the foundation of our technology-driven 

society; (2) disseminate technologies by which these physical parameters can be accessed in a 

standardized way by the stakeholders; and (3) conduct research at both fundamental and applied levels to

provide knowledge that may eventually lead to advances in measurement approaches and standards.

The scientific staff is of uniformly high quality, but preserving the quality of the staff will be a 

challenge because of the large number of anticipated retirements of such excellent staff. The physical 

infrastructure of the PML is heterogeneous and complex but still fundamentally adequate to the tasks at 

hand. It is generally of a world-class quality, although there remain some weak infrastructure areas in the 

Radiation Physics Division that need to be addressed immediately.

The PML is a large organization, dispersed on two main campuses, one at Gaithersburg, 

Maryland, the other at Boulder, Colorado.

It is vital that the excellence of the PML be maintained as the United States faces increasing 

competition for resources and technology from rapidly advancing countries.

 1 Effective July 1, 2015, the institution is called the National Academies of Sciences, Engineering, and 

Medicine. References in this report to the National Research Council are used in a historical context identifying 

programs prior to July 1.
2

SIGNIFICANT ACCOMPLISHMENTS

Applied Physics Division

Electron beam lithography has been used by the Applied Physics Division (APD) to pattern 

nanowires into a thin film made of a heat-tolerant ceramic superconductor, molybdenum silicide, operated 

at the superconducting transition edge temperature. The new design operates at higher temperatures and 

bias current. Timing jitter is now 76 picoseconds, and detector quantum efficiencies are 87 percent at 

wavelengths that are useful in telecommunications.

Quantum Electromagnetics Division

The Quantum Electromagnetics Division (QED) has developed a new type of sensor that can be 

used to investigate the isotopic composition of plutonium samples, a critical measurement for nuclear 

nonproliferation efforts and related forensics, as well as for environmental monitoring, medical assays, 

and industrial safety.

Engineering Physics Division

The Engineering Physics Division (EPD) has developed a system for forensic analysis of spent 

bullet casings. Use of microscope images of three key markings typically found on spent cartridge cases

dramatically reduces the uncertainty levels for the firing pin and breech face markings, which 

investigators can use to determine their confidence levels about a match.

Office of Weights and Measures

The Office of Weights and Measures (OWM) has proposed a standard for plug-in electric car 

customers to standardize what they should be charged for their electrical charge, and what requirements 

operators should meet. This standard, produced by NIST’s U.S. national work group on electric vehicle 

refueling and submetering, was adopted by the National Conference on Weights and Measures (NCWM) 

at its 2015 annual meeting.

Quantum Measurement Division

The Quantum Measurement Division (QMD) has performed experimental studies of many-body 

effects in ultracold atomic systems that are among the best in the world, and the recent test of Bell 

inequalities, eliminating the remaining loopholes of previous experiments, is a telling example of the 

synergy between different areas of expertise in Gaithersburg and at JILA, a joint institute of NIST and the 

University of Colorado, Boulder.

Quantum Physics Division

The work on spin exchange of ultracold molecules is a new testing ground, enabled by tools 

that have been developed at the Quantum Physics Division (QPD). It will address fundamental 

questions of molecule–molecule interactions and can be used as a quantum simulator of many-body 

spin dynamics.
3

Radiation Physics Division

The Radiation Physics Division (RPD) has implemented a new Co-60 therapy-level calibration 

facility with state-of-the-art data acquisition and operating capabilities. It is expected to help improve the 

ability to maintain a number of dosimetric standards essential to the radiation oncology community. 

Sensor Science Division

The Sensor Science Division (SSD) has performed work on characterization of hydrogen flow 

meters for high-pressure refueling of hydrogen-powered vehicles, with reduced uncertainty and rapid 

response times. A portable field test standard has been developed for use at refueling stations. This work 

is important as the world seeks alternatives to fossil fuels. 

Time and Frequency Division

The Time and Frequency Division (TFD) has generated optical frequency combs through 

nonlinear wave mixing in optical microresonators. Such microcombs offer dramatic size reduction 

compared to frequency combs derived from mode-locked lasers, opening the possibility of applications 

beyond specialized laboratory settings. Researchers have developed new methods for fabricating highquality-factor optical microresonators at low cost and high speed. 

KEY SUGGESTIONS FOR IMPROVEMENT

The quality of work done at the PML and its response to the stakeholders whose interests the 

PML addresses are excellent. Each division deserves high accolades.

Applied Physics and Quantum Electromagnetics Divisions

The restructuring of the former Quantum Electronics and Photonics Division and the 

Electromagnetics Division into the Applied Physics Division (APD) and the Quantum Electromagnetic 

Division (QED) seems to have been accomplished smoothly. However, the decision by the PML to have 

the panel jointly review the two divisions as one entity has created some confusion and did not allow an 

in-depth analysis of each division. The APD as a consequence needs to be analyzed in more depth in 

coming reviews to provide a clearer view of its mission and how it fits into the overall PML effort.

Engineering Physics Division

It will be important that the Engineering Physics Division (EPD) avoid duplication of effort in the 

area of nontraditional materials conducted by better-funded teams investigating the science or technology 

of these speculative materials systems.
4

Quantum Electromagnetics Division

The Quantum Electromagnetics Division’s (QED’s) optical quantum entanglement work was not 

at the fundamental leading edge of such work, which is being carried out by many other groups 

worldwide. It would be worthwhile to focus more on areas where the division has real strengths, such as 

photon sensors.

The work in nuclear magnetic resonance (NMR) imaging, while strong, needs to be expanded to 

include the rapidly growing area of functional NMR imaging (fMRI), so that claims made in the literature 

can be evaluated more carefully.

The Quantum Sensors group has had a significant impact in millimeter wave polarimetry with its 

detector arrays, but the group serves so many external groups that it runs the risk of becoming

oversubscribed.

PML staff suggested that the Gaithersburg and Boulder nanofabrication facilities could support a 

significantly greater number of NIST projects or outside collaborators. The new facility established at the 

University of Maryland further disperses the division and could present difficulties for its current 

cohesiveness and collaborations.

PML staff report that overhead charges on graduate students and on capital equipment are 

excessive. 

Office of Weights and Measures

The effort by the metric program in the Office of Weights and Measures (OWM) to implement 

the SI units in the United States is lagging. Better quantitative metrics for the effectiveness of the Legal 

Metrology group needs to be established. The number of accredited and recognized laboratories at the 

state level for dissemination of mass and volume standards for stakeholders is declining. 

PML predicts a large wave of retirements (50 percent of staff) in this office in the coming 5 years, 

and PML needs to examine the implication of the retirements and determine what replacements, if any, 

will be required. 

Quantum Measurements Division

The partial relocation of the groups working in the Quantum Measurements Division (QMD) to 

the University of Maryland campus as the Joint Quantum Institute presents both opportunities and 

challenges and warrants careful monitoring so that the groups do not become isolated.

It will be important that the Synchrometrology Group have sufficient resources to play a role in 

the upcoming renovation of the national power grid into a smart grid. This effort will have a worldwide 

scope.

Quantum Physics Division

The powerful Quantum Physics Division (QPD) has successfully evolved new opportunities from 

initial objectives. The group may be rapidly evolving toward nanotechnology and biotechnology; it may 

be worthwhile to plan for this evolution rather than expect it to occur organically.

The scientific interests of the division show strong overlap with those of the Time and Frequency 

Division, but given that both divisions have been extremely successful, this can be viewed as increasing 

critical mass in areas in which NIST is a world leader. 

The activities in biological physics have not been well integrated with those of other efforts 

within the QPD. PML needs to examine the relationship of biology to other division efforts. The division 
5

needs to develop firm guidelines for a consistent and clear approach to the development of intellectual 

property.

Several staff spoke of a high overhead rate on capital equipment; they suggested that this makes 

acquisition of expensive equipment very difficult.

Radiation Physics Division

Building 245 in which the Radiation Physics Division (RPD) is primarily housed, is approaching 

a dangerous and unsafe condition; immediate attention is warranted. In the laboratories of Building 245, 

where most of the radionuclide standards are prepared for shipment, the rooms are old and lacking in 

proper heating and ventilation, with consequent inadequate control of humidity and temperature. Neutron 

source standardization is carried out in a number of shielded, below-grade laboratories in Building 245.

Water intrusion during heavy rains has become an issue because the building is no longer watertight.

Dispersal of the source material is remotely possible, but the immediate concern is damage and loss of 

calibration traceability. These events are, at a minimum, distractions to overburdened scientists, and in 

some cases have threatened to flood sources under test.

The Dosimetry Group primarily works with its large stakeholder community. Providing more 

opportunity and support to do research would enhance the quality of the staff and the work done.

Lack of funds is resulting in nonreplacement of retiring critical employees and in requiring Ph.D.-

level staff to do routine tasks, stealing time from their technical work. Unfortunately, there are examples 

where dissemination of proper radioactivity standards has not been able to proceed as rapidly as required 

owing to a lack of funds.

The division needs to strengthen the training program that involves students and postdoctoral 

researchers in each of the critical standards activities and to foster a program to share equipment and 

facilities with users at other national laboratories and universities.

Sensor Science Division

One possible caution for the Sensor Science Division (SSD) concerns the increasing emphasis on 

lower-cost, lower-SWAP sensors for future satellite systems. The division could prepare to calibrate 

much smaller radiometers for its customers. As microfluidics becomes ever more important, it will be 

correspondingly important to continue developing noninvasive and inline ways to determine microflows.

While the overarching strategy was well articulated, the division did not describe plans for some 

of the projects, particularly those that are funded externally; those working on internally funded initiatives 

seemed to have more concrete plans. The division needs to clarify plans for externally funded projects.

Retirements are being delayed because of difficulties in finding appropriate replacements.

Time and Frequency Division

The NIST-on-a-Chip effort will involve this division, which needs to expand development of its 

roadmap for this work. The Time and Frequency Division’s (TFD’s) scientific expertise evident during 

the review was primarily of an experimental nature. As stabilities and accuracies of frequency standards 

continue to improve, strong theoretical support will be required. The division needs to consider whether 

the theoretical expertise resident within the division is sufficient to support future experimental efforts.

TFD staff have mentioned the shortage of meeting and collaboration space. Staff also expressed 

concern about the onerous procurement process, which, they said, incurs substantial delays. 
6

The emphasis on patent preparation does not appear to be stable from year to year. A careful 

assessment by the division of the value of patenting would be worthwhile. Once the value proposition is 

in hand, more consistent direction to staff can be provided.
7

1 

The Charge to the Panel and the Assessment Process

At the request of the National Institute of Standards and Technology (NIST), the National 

Academies of Sciences, Engineering, and Medicine has, since 1959, annually assembled panels of experts 

from academia, industry, medicine, and other scientific and engineering communities to assess the quality 

and effectiveness of the NIST measurements and standards laboratories, of which there are now seven,1 as 

well as the adequacy of the laboratories’ resources.

At the request of the Director of NIST, in 2015 the National Research Council (NRC) formed the 

Panel on Review of the Physical Measurement Laboratory at NIST and established the following 

statement of task for the panel:

The National Research Council shall appoint a panel to assess the scientific and technical work 

performed by the National Institute of Standards and Technology (NIST) Physical Measurement

Laboratory (PML). This panel will review technical reports and technical program descriptions 

prepared by NIST staff and will visit the facilities at the Physical Measurement Laboratory. Visits 

will include technical presentations by NIST staff, demonstrations of NIST projects, tours of NIST 

facilities, and discussions with NIST staff. The panel will prepare a report summarizing its 

assessment findings.

The context of this technical assessment is the mission of NIST, which is to promote U.S. 

innovation and industrial competitiveness by advancing measurement science, standards, and technology 

in ways that enhance economic security and improve the quality of life. The NIST laboratories conduct 

research to anticipate future metrology and standards needs, to enable scientific and technological 

advances, and to improve and refine existing measurement methods and services.

NIST specified that the nine divisions of the Physical Measurement Laboratory (PML) would be 

reviewed: the Applied Physics Division (APD), Engineering Physics Division (EPD), Quantum

Electromagnetics Division (QED), Office of Weights and Measures (OWM), Quantum Measurement 

Division (QMD), Quantum Physics Division (QPD), Radiation Physics Division (RPD), Sensor Science 

Division (SSD), and Time and Frequency Division (TFD). To accomplish the assessment, the NRC 

assembled a panel of 26 volunteers whose expertise matched that of the work performed by the PML 

staff.2

On September 9, 2015, a subset of the panel assembled at the NIST facility in Boulder, Colorado,

for a two-day assessment, and on September 29 the full panel assembled at the NIST facility in 

Gaithersburg for a two-and-a-half-day assessment. Each panel member was assigned to one of the nine

teams, each of which reviewed one of the PML divisions. The full panel then met to deliberate on its 

findings and to define the contents of this assessment report.

 1 The seven NIST laboratories are the Engineering Laboratory, the Physical Measurement Laboratory, the 

Information Technology Laboratory, the Material Measurement Laboratory, the Communication Technology 

Laboratory, the Center for Nanoscale Science and Technology, and the NIST Center for Neutron Research. 2 See the NIST PML website at http://www.nist.gov/pml/ for information on the PML organization and 

programs (accessed November 11, 2015).
8

The panel’s approach to the assessment relied on the experience, technical knowledge, and 

expertise of its members. The panel reviewed selected examples of the technical research performed at the 

PML; because of time constraints, it was not possible to review the PML programs and projects 

exhaustively. The examples reviewed by the panel were selected by the PML. The panel’s goal was to 

identify and report salient examples of accomplishments, challenges, and opportunities for improvement 

with respect to the factors suggested above by the director of NIST. These examples are intended 

collectively to portray an overall impression of the laboratory, while preserving useful suggestions 

specific to the projects and programs that the panel examined. Given the necessarily broad and

nonexhaustive nature of the review, omission in this report of any particular PML program or project 

should not be interpreted as implying any negative reflection on the omitted program or project.
9

2

Applied Physics and Quantum Electromagnetics Divisions

INTRODUCTION

The Applied Physics Division (APD) and the Quantum Electromagnetics Division (QED) were 

recently formed by a restructuring of the former Quantum Electronics and Photonics Division and the

former Electromagnetics Division. This restructuring came about as a consequence of the formation of the 

NIST Communications Technology Laboratory, to which roughly 67 staff members of the two former 

PML divisions were transferred. Because the two new divisions have considerable overlap of activities 

and focus, they were assessed together. 

These divisions have aligned their activities into five focus areas: quantum information, nanomagnetics, imaging science and technology, sensing, and measurement services and standards.

Applied Physics Division

The APD develops measurement science over broad spans of the electromagnetic spectrum, 

addressing national priorities that include advanced manufacturing, national security, quantum science, 

climate change, and biomedical imaging. It consists of seven technical groups: Advanced Microwave 

Photonics Group, Faint Photonics Group, Fiber Sources and Applications Group, Magnetic Imaging 

Group, Sources and Detectors Group, Quantitative Nanocharacterization Group, and Quantum

Nanophotonics Group.

The Advanced Microwave Photonics Group focuses on microwave generation and detection of 

quantum information (QI) for both quantum communication and computation. The Faint Photonics Group 

addresses few-photon generation and detection for quantum communication and secure random number 

generation. The Fiber Sources and Applications Group addresses high-power lasers and their application 

to manufacturing. The Magnetic Imaging Group addresses calibration and standardization of magnetic 

resonance imaging (MRI) and interfaces with an MRI industry standards group. The Sources and 

Detectors Group develops high-dynamic-range laser power metrology over a broad spectral range. The 

Quantitative Nanocharacterization Group develops novel optoelectronic scanning probes for a variety of 

applications, including semiconductor technology, condensed matter physics, biology, and medicine. The 

focus of the Quantum Nanophotonics Group is on using the entanglement of quantum states to encode 

information and by applying techniques for manipulation and measurement of the quantum states of 

atoms, ions, spins, superconductors, and cavity quantum electrodynamics (cavity QED). 

Quantum Electromagnetics Division

The QED investigates foundations of techniques for metrology of electronic, magnetic, and 

photonic technologies. It develops devices, systems, standards, and measurement methodologies to 

address national needs in these areas of technology. It consists of seven technical groups: 

Microfabrication Group, Molecular and Bio-Photonics Group, Nanoscale Spin Dynamics Group, 
10

Quantum Processing Group, Quantum Sensors Group, Superconductive Electronics Group, and Spin 

Electronics Group.

The Microfabrication Group runs the recently built microfabrication clean room facility, which 

houses the molecular beam epitaxy (MBE) epitaxial materials facility, designed for processing the unique 

materials required for the extensive experimental QI research programs at NIST. The Molecular and BioPhotonics Group specializes in quantitative medical imaging using a variety of optical methods. The 

Nanoscale Spin Dynamics Group develops metrology and studies fundamental physics of 

magnetodynamics in nanoscale magnetic devices and model systems. The focus of the Quantum 

Processing Group is development of novel materials, devices, and measurements for the integrating

quantum systems in information processing architectures. The Quantum Sensors Group develops 

advanced superconducting photon detectors and amplifiers that are sensitive on the single-photon level 

over a broad spectral range and applies them to diverse fields such as astrophysics and chemical 

dynamics. The Spin Electronics Group develops metrology and fundamental understanding of spin 

currents and their application in nanoscale magnetic devices and hybrid magnetic/superconducting 

memory devices. The Superconductive Electronics Group develops and characterizes voltage standards 

based on quantized magnetic flux in superconducting Josephson devices and investigates devices for 

advanced computers based on superconducting logic and memory. 

ASSESSMENT OF TECHNICAL WORK AND DISSEMINATION OF OUTPUTS 

Quantum Information

Quantum Optics and Processing

Quantum optics and processing activities fall under the overall topic of quantum processing,

which includes novel measurements and devices for the integration of quantum systems into information 

processing architectures. On a larger scale, QI is the application of ideas of quantum physics to the area of 

information sciences.

An important matter being addressed is using the principle of entanglement by encoding 

information in the quantum mechanical state, which involves the manipulation and measurement of 

quantum states of atoms, ions, spins, superconductors, and cavity quantum electrodynamics. The group is 

creating tools for generating, manipulating, detecting, and measuring photons under various conditions. 

Transportation of information encoded using quantum states of matter or light has been shown to 

be desirable by assuring that unauthorized eavesdroppers cannot decode the information. This is often 

called teleportation of information, which is a subject of intense research activity around the world. The 

quantum information subgroup within the Faint Photonics Group and the Quantum Nanophotonics Group

has demonstrated quantum teleportation over a distance of 100 km of optical fiber, which is 

approximately four times that of the previous record. This feat was possible because of the highefficiency single-photon detector capability, which is described in the quantum sensors section of this 

chapter. Teleportation over optical fibers brings the ability to transmit quantum encoded information into 

the practical realm.

Application of quantum physics to the area of information sciences involves the use of ion traps 

that retain the ions for a long time, which requires reduction of anomalous heating that results from 

surface contamination and ordering. Paying special attention to cleaning of the surfaces reduces heating. 

The group has attained a 100-fold decrease in ion trap heating rates via in situ cleaning of carbon 

contamination, which allows the traps to operate with much lower ion height. Quantum computing may 

have immediate application in the area of true random number generation.

This activity at the Applied Physics Division is among the many similar outstanding activities 

around the world. The division’s activity is not at the fundamental leading edge of science, but it is taking 
11

advantage of the superb photon sensors that the PML has developed. This activity is contributing well 

toward bringing QI science into practice, even though it may take many years to accomplish that.

Advanced Microwave Photonics

The microwave photonics effort in the QI and measurements project is impressive. The creation 

of entangled photons is a major challenge for quantum computing. Making use of microwave 

nonlinearities for generation and detection of QI greatly reduces both fabrication and instrumentation 

challenges in exchange for carrying out the experiments at much lower temperatures, less than 30 mK.

Progress in low-temperature technology over the past decade and readily available, well-established, and 

extensive microwave instrumentation make this an excellent trade-off, particularly in light of the strong 

PML expertise in superconductive materials, device design, and characterization.

Creation of controlled-NOT (C-NOT) gates and experimental investigation of QI are impressive. 

This is part of the more extensive QI project that covers both more conventional photonic and 

superconducting Josephson junction approaches, so the entire effort is highly complementary and covers a 

broad range of approaches in this very challenging, long-range program.

Quantum Nanophotonics

The focus of the integrated photonics effort is the development of a quantum repeater for 

quantum communications. Quantum optical communications requires generation and detection of single 

photons to produce entangled photon pairs. The project is developing sources and detectors for quantum 

states of light based on self-assembled quantum dots embedded in high-Q photonic crystal optical cavities 

for application to single-photon sources, laser diodes, and quantum optical metrology. Integrated quantum 

dot gain regions in high-Q cavities produce very short radiative emission times, increasing the speed and 

efficiency of the light source, which are critical enablers for quantum communications.

The Quantum Nanophotonics Group has demonstrated both quantum-dot-based detectors and 

lasers of single photons that are unique in the compound semiconductor device world. The group recently 

demonstrated a wavelength bistability phenomenon in a monolithic quantum dot laser. This effort couples 

well with the efforts of other PML groups in the quantum information program.

Nanoscale Magnetics

Spin Electronics and Nanoscale Spin Dynamics

The projects of the Spin Electronics Group and the Nanoscale Spin Dynamics Group build on 

their previous work on understanding and measuring the magnetic behavior of microscopic ferromagnetic 

film devices. These groups continue to demonstrate the world's fastest measurement of magnetization 

dynamics. The groups also demonstrate microwave ferromagnetic resonance measurement of the smallest 

magnetic features with the highest dynamic range. It now appears that magnetic switching by use of spin 

currents will play an important role in future magnetic storage devices. The work of these two groups 

continues to provide a fundamental understanding of these phenomena. People in industry will use this 

work for guidance on how to make these extremely difficult measurements, which will be essential for

understanding the failure modes of nanoscale spintronics in commercial applications.

Several important investigations push the frontiers of magnetic-based oscillators and of our 

understanding of dynamic effects (such as magnetic damping during switching). Others provide insight 

into the thermal stability of microscopic-domain configurations (i.e., stored bits). The data obtained and 

the techniques perfected are certain to prove useful in the development of future low-power, high-speed 
12

computers. This work is entirely in line with the NIST directive to further the national strategic 

computing initiative.

Imaging Science and Technology

Magnetic Imaging

The biomagnetic imaging program focuses on several issues related to MRI. Central to these 

efforts is the development of techniques that make it possible to ensure that the images produced with 

different scanners will reflect underlying pathologies in a consistent manner. At the heart of these efforts 

is the development of standardized phantoms, nonbiological fabricated artifacts that can be imaged in an 

arbitrary scanner to identify differences in the images produced by different machines. A particularly 

good example is a head phantom that contains an array of solutions designed such that each has a welldefined diffusion coefficient for water. Diffusion is often used as a contrast mechanism in MRI, and it can 

be very important for diagnosing conditions such as traumatic head injury. Diagnosing such injury, 

however, requires making subtle distinctions that require high levels of standardization in the response of 

the scanner if results are to be compared from one machine to another. The head phantoms are now being 

commercialized and are undergoing clinical trials. Another example is breast phantoms that simulate the 

healthy tissue. It can often be the case that a scanner will produces images with what appear to be 

morphological anomalies, potentially tumors, that are in fact nothing more than artifacts traceable to 

imperfections in the MRI scanner. Having a standardized phantom that is known to have no features 

corresponding to tumors makes it possible to ensure that a particular scanner will not be prone to 

producing false positive results.

Another area of focus in the biomagnetic imaging program is the study of so-called MRI contrast 

agents. Historically, contrast agents have been largely limited to injectable substances that, when present, 

increase the brightness of the MR image. Gadolinium-based compounds, for example, have been very 

useful for visualizing vasculature. One can imagine, however, contrast agents that provide sensitivity to 

different biological or chemical characteristics. One PML-developed contrast agent utilizes 

nanofabricated structures that respond resonantly to radio-frequency (RF) radiation. The resonant 

frequency of these structures is sensitive to the local pH, making it possible to use MRI to visualize 

certain details of physiological processes. The approach of using such nanofabricated structures has 

considerable potential for future applications as well.

Molecular and Biophotonics

The Molecular and Biophotonics Group works to develop methodologies for quantitative optical 

medical imaging based on several diverse techniques, including optical coherence tomography (OCT), 

hyperspectral imaging (HSI), photoacoustic imaging, and light scattering methods. They do this by 

advancing measurement science supporting these techniques and by developing calibration and 

characterization tools that can make these technologies quantitative and international system of units (SI)

traceable. This effort to standardize and develop quantitative tools is of key importance and has the 

potential for significant impact in laying a foundation for reproducible medical research that can be 

applied to recognize biomarkers for early disease recognition and to measure short- and long-term 

response to therapy. Optical imaging methods are advantageous in being mostly noninvasive, utilizing 

nonionizing radiation, and providing high-resolution, label-free imaging.

Examples of recent technical accomplishments include improvement of OCT resolution to 1 μm, 

label-free chemical mapping of subcellular molecules at the single-cell level using HSI, and the 

development of a unique hyperspectral dark field microscope for optical biopsy. This microscope has 

been deployed in a clinical environment to address a particular deficiency in the rapid, accurate 
13

determination of tumor margins in breast cancer, which currently leads to the need for additional surgeries 

in about half of lumpectomy patients. The rapid-turnaround detection of precise tumor margins available 

once this instrument is present in the operating room will allow surgeons to make decisions in real time 

and reduce the likelihood of second surgeries.

Relatively few of the large number (∼160,000) of biophotonics-related patents have penetrated 

the market to become devices approved by the Food and Drug Administration (FDA). Thus, a particular 

challenge and significant opportunity for external impact is to enable accelerated FDA approval for 

advanced biophotonic imaging methods. The PML addresses this issue by developing quantitative 

standards that help to improve measurement quality and lead to faster FDA approval for tools developed 

by the biophotonics community. Advances toward this goal will be key in maximizing the impact of 

advanced optical imaging on future delivery of health care. This group has a variety of external 

collaborators, including academic institutions, instrumentation companies, and other government 

agencies. Further evidence of the technical quality and success in dissemination of the results of the

group’s efforts is the output of published papers and invited talks (about five per year of each for the past 

few years).

Quantitative Nanocharacterization

The Quantitative Nanostructure Characterization Group has developed an advanced 

optoelectronic probe tip for near-field scanning microscopy that is based on the integration of gallium 

nitride nanowires with silicon scanning probe cantilevers. They have perfected the growth of these 

nanowires and demonstrated their use as probe tips for scanning microwave microscopy measurements of 

carrier concentration and conductivity in semiconductor nanostructures and 2D electronic materials, an 

application where the exceptional durability of the nanowire tips has enabled more quantitative 

measurements. The nanowires can also be doped during growth and potentially excited electrically as a 

light-emitting diode, providing simultaneous force, optical, and microwave susceptibility sensing. This 

will enable simultaneous detection of changes in electrical properties upon optical excitation directly from 

the scanning probe, with high temporal and spatial resolution, for example, when applied to 

characterization of photovoltaic materials.

The realization of this optoelectronic nanowire probe presents a difficult technical challenge. The 

eventual impact of this technique on advanced manufacturing remains unclear; the demonstration of its 

application to the solution of a key measurement problem of importance to industry would be a significant 

advance.

Precision Imaging

The precision imaging facility has impressive capabilities for materials characterization at the 

atomic and nano scales. These capabilities are primarily used to support the other materials development 

capabilities, as well as outside clients who have specific metrology needs that can be served by use of 

these tools. The tools appear to be staffed by highly knowledgeable scientists who publish their work 

frequently in archival journals and at conferences. Two of the many noteworthy instruments/capabilities 

are the He ion microscope and the near-field scanning microscope.

The He ion microscope is a new instrument that has been purchased because of its exceptionally 

large depth of field—an extremely important capability for imaging nanostructures with considerable 

surface morphology. The second unique capability is a near-field microscope using light-emitting GaN 

tips. These tips require a considerable degree of expertise to fabricate, but ultimately they allow for the 

local (at the nano scale) illumination of a sample to observe separate optically active regions. Several 

other, more standardized pieces of equipment comprise the suite of capabilities in the 3,000 ft2 facility. 

The facility appears to be well supported by NIST.
14

The capabilities and high-quality staffing of the facility play an essential role in supporting both 

the internal (to NIST) and external materials research communities in the United States.

Sensing

Quantum Sensors

Quantum sensors activities cover precise measurements of the energy carried by photons or 

particles, the development of sensors, and supporting technology to perform these measurements and 

apply these sensors to problems with scientific and technological relevance. The core technologies 

include transition-edge-sensor (TES) calorimeters, superconducting quantum interference devices 

(SQUID) readouts, and superconducting microresonators.

The photon detection capability developed by the Quantum Sensors Group is now made available 

for application to practical problems. Application areas include astrophysics, x-ray physics, and 

laboratory science. The group is among the best in the world in the fabrication of high quantum efficiency 

integrated transition edge sensors (TES) and ultra-low-noise SQUID readouts for photon detection over a 

broad range of photon energies. The group expects to reach nearly unity detection efficiency in the future.

Upon detection of an incident photon, the signal magnitude is proportional to the photon energy; the TES 

thus functions as a spectrometer as well as a detector. The TES has shown the capability to reproduce

detection of one and more photons. When compared with other gamma-ray sensors the TES sensors show 

much higher resolution and sensitivity. TES detectors are being integrated into spectrometers deployed in 

the National Synchrotron Light Source and the Advanced Photon Source. The group also has an x-ray 

spectrometer under construction for the Stanford Synchrotron Radiation Light Source. A 16 pixel version 

has been commercialized for semiconductor defect analysis. For analysis of plasma sources, which are 

very dim compared to the synchrotron sources, the high-resolution, high-efficiency detectors’

superconducting x‐ray sensors fabricated by the group are ideal for measurements at the 10−12 meter scale 

and the 10−12 second time scale for dynamic measurements.

This group is very successful in technology transfer to private industry, to academic and 

government laboratories, and for astronomy polarimeters, where more than 20 installations of 

TES/SQUID-based detectors and detector arrays are playing a central role in millimeter wave polarimetry 

in astrophysical cosmology. PML detectors and/or amplifiers are in almost all millimeter wave 

polarimeters in the field, because these detectors provide the best performance.

This Quantum Sensors Group and the Quantum Nanophotonics Group have also built a unique 

tabletop time-resolved x-ray spectrometer based on a femtosecond laser source that is focused into a 

water jet to generate pulses of x rays. The high sensitivity and quantum efficiency of the TES sensors are 

a good match to the relatively low x-ray flux, and this is the key enabler that makes this experiment 

possible without the high x-ray flux of a synchrotron or free-electron laser source. This instrument is used 

in novel studies of chemical dynamics through time-resolved, x-ray, near-edge spectroscopy and x-ray 

absorption fine structure.

The PML group deserves congratulations for the success of its TES activity, which has resulted in 

a uniquely versatile and capable detector technology that has been successfully propagated to many 

laboratories around the world.

Precision Optical Measurements

The Fiber Sources and Applications Group demonstrated a new technique based on dual 

frequency comb spectroscopy that can accurately measure amounts of major greenhouse gases. The 

concept entails sending a laser beam across a 2 km round trip path from NIST to a mirror mounted on the 

side of a nearby mesa. This provides a test column whereby even trace amounts of methane can be 
15

detected with very high sensitivity. The research team has collected data under real conditions and 

compared the data against data collected at a nearby National Oceanic and Atmospheric Administration 

(NOAA) point sensor under well-mixed atmospheric conditions. 

The PML measurements yielded concentration uncertainties of less than 1 ppm for carbon 

dioxide, validating the concept. The group has extended this method to differential absorption light 

detection and ranging (LIDAR) that measures both mass flux and gas content along this volume as a 

means of obtaining the distribution of greenhouse gases. This allows for pinpointing local sources and 

perhaps ultimately their remediation. Extension to portable laser systems, which is one focus of this team, 

will enable its widespread deployment to sites around the United States and worldwide to help in the 

accurate measurement of greenhouse and other atmospheric contaminants and of their sources. This is a 

vital precision measurement capability that lies at the core of the NIST mission of determining the trace 

presence of contaminants and other materials in the environment.

Measurement Services and Standards

Superconductive Electronics

The Superconductive Electronics Group has created and maintains both direct current (DC) and 

alternating current (AC) voltage standards based on the Josephson effect. The quantization of magnetic 

flux in a Josephson junction make this device a perfect frequency-to-voltage converter; since frequency is 

perhaps the most precisely defined quantity, this provides a path to a very precise voltage standard.

Realization of a voltage standard requires synchronous operation of a large number of junctions 

in series, which is enabled by the excellent microfabrication facilities that are part of the Quantum 

Electromagnetics Division. The resulting programmable DC voltage standard has demonstrated accuracy 

to a few parts in 1011, has been disseminated to national metrology institutes (NMIs) around the world, 

and is available for sale as a certified NIST reference instrument. This group is the best in the world in 

AC waveform synthesis with quantum-derived accuracy and in the electronic measurement of 

Boltzmann's constant to 3 ppm accuracy.

The Superconductive Electronics Group also works to develop superconductive logic and 

memory devices for advanced high-performance computing. This is a national priority area identified in 

the National Strategic Computing Initiative, and the group is well suited and equipped to make advances 

in superconducting computing.

Laser Metrology and Applications

The Sources and Detectors Group has performed impressive laser metrology work. Because of 

the extreme sensitivity of the welding process to the control of laser welder power. PML involvement in 

setting power measurement standards is important to the U.S. economy.

The work on metrology is very imaginative and impressive. The standard approach is to measure 

coolant temperature changes from output absorption in metal power-absorbing cells. This method is 

effective and reasonably accurate; however, it is expensive and does not clearly provide a portable 

standard that can be used in house by any but the most substantial laser welder manufacturers or users. 

The new approach being explored by the Sources and Detectors Group is to measure radiation pressure 

using commercially available scales. The power is measured by determining the change in scale reading 

in the presence of and the absence of the incident beam. The method is very inexpensive and may provide 

the accuracy required for many manufacturing needs.

The purchase of a new welding tool is an important addition to the metrology group, which can 

do real-time experiments to determine the variables that need to be measured and controlled in practical 

welding applications. The group already has proficiency in its use.
16

The Laser Metrology Group is doing excellent work in support of this broad-spanning and crucial 

component of our national economy. The group holds a global leadership position in high-power laser 

metrology.

PORTFOLIO OF SCIENTIFIC EXPERTISE

The permanent staff members of the APD and the QED form a talented group, as evidenced by 

their scientific output, the recognition of 3 of their staff as NIST fellows, and of 14 of them as fellows of 

scientific professional organizations, and by their recognition as recipients of 8 external awards and 32

NIST or Department of Commerce awards since 2010. They are active and well recognized for their 

contributions to conference organizations and professional societies. They have averaged about 5 refereed 

publications per staff member since 2013, for a total of over 250 publications. Their publications were 

cited 5,335 times in 2014. These scientists exhibited exceptional depth of knowledge and understanding 

of their fields of expertise.

ADEQUACY OF FACILITIES, EQUIPMENT, AND HUMAN RESOURCES

The MBE laboratories and microfabrication facilities in Boulder and in Gaithersburg are 

impressive and are designed for the processing of the unique materials and devices required for research, 

including the extensive experimental QI research programs at NIST.

The MBE systems in Boulder and Gaithersburg are very new and state-of-the-art. Both facilities 

have excellent capabilities for growth and optical characterization of the unique quantum structures that 

are being grown to support the quantum device projects on entangled photons and single-photon 

detectors.

The state-of-the-art Boulder Microfabrication Facility (BMF) provides clean-room facilities and 

fabrication tools vital to the success of many of the technical groups, such as the Quantum Sensors and

Superconductive Electronics Groups. The BMF has impressive capabilities for materials deposition and 

for sophisticated fabrication of superconductive tunnel junctions and semiconductor quantum well, dot, 

and nanowire structures.

The precision imaging facility (PIF) offers a variety of microscopy tools, including some 

relatively uncommon techniques such as local-electrode atom probe and helium ion microscopy.

The Gaithersburg and Boulder nanofabrication capabilities are complementary; the Gaithersburg 

facilities address Si complementary metal-oxide-semiconductor (CMOS) technology but are unable to 

meet the demands for the combination of materials grown and processed in Boulder. The processing 

facilities are state-of-the-art and appear to be staffed by knowledgeable personnel and utilized by a broad 

range of scientists in the Advanced Microwave Photonics, Magnetic Imaging, Sources and Detectors, 

Quantitative Nanocharacterization, Quantum Sensors, Superconductive Electronics, Quantum Processing 

Faint Photonics, and Quantum Nanophotonics groups. The scientists using these facilities publish their 

work frequently and are active in their respective technical communities.

As an example of the quality of work in the APD, electron beam lithography has been used to 

pattern nanowires into a thin film made of a heat-tolerant ceramic superconductor, molybdenum silicide, 

operated at the superconducting transition edge temperature. The new design operates at higher 

temperatures and current. Timing jitter is now 76 picoseconds and detector efficiencies are at 87 percent 

at wavelengths that are useful in telecommunications.

1

 1 V.B. Verma, B. Korzh, F. Bussières, R.D. Horansky, S.D. Dyer, A.E. Lita, I. Vayshenker, F. Marsili, M.D. 

Shaw, H. Zbinden, R.P. Mirin, and S.W. Nam, High-efficiency superconducting nanowire single-photon detectors 

fabricated from MoSi thin-films, Optics Express 23(26), 2015, 33792-33801, doi:10.1364/OE.23.033792.
17

In the QED, a significant and important advance has been the development of a new kind of 

sensor that can be used to investigate the isotopic composition of plutonium samples—a critical 

measurement for nuclear nonproliferation efforts and related forensics, as well as environmental 

monitoring, medical assays, and industrial safety.

PML staff suggested that the Gaithersburg and Boulder nanofabrication facilities could support a 

significantly greater number of NIST projects or outside collaborators. These are valuable resources that 

are not readily available to the growing user community outside NIST.

The Gaithersburg microfabrication facility is older and has been substantially upgraded. A new 

facility has been established at the University of Maryland.

The recent reorganization of these divisions has balanced the numbers of their staff, with 101 fulltime employees and affiliates in the Applied Physics Division and 103 full-time employees and affiliates

in the QED, while retaining a distribution across the five focus areas. About a third of the technical 

personnel in each division are permanent federal employees, with the remainder being mostly affiliates 

(guest researchers) and federal term employees (postdoctoral researchers). While recent construction has 

provided new, advanced laboratory space for much of the work in these divisions, the number of

postdoctoral researchers has not increased.

It was also noted by the PML that graduate student hiring is substantially hindered by the practice 

of charging full NIST overhead on the cost of the student, which is then passed to the university, which 

charges full overhead again on the cost of the student. The resulting concatenation of overheads 

substantially exceeds 100 percent. 

There are few technical support staff members, such as machinists, mechanical designers, 

instrument builders, and electronics technicians in residence for the areas of applied physics and quantum 

electromagnetics. This work is divided between external contractors and the special shop facilities 

personnel at JILA (the joint institute between NIST and the University of Colorado). Continued access to 

the JILA shops and continued funds supporting work done by external vendors is important for the

technical work in these two divisions.

It was also noted by the PML that investments in new capital equipment are charged overhead 

proportional (approximately 50 percent) to the full amount of the capital cost. This is a serious limitation 

to the investment in the equipment necessary to maintain the high level of productivity of these two 

divisions and the PML more generally.

CONCLUSION

The activities in the APD and the QED are well aligned to address the priorities of the PML 

mission. These priorities are advanced measurement dissemination, photonics, measurement science for 

future computing devices, quantum information, and physical measurements in biophysics and 

biomedicine. These divisions excel at advancing the frontiers of measurement science through new 

technology and at making sure this technology has impact through dissemination of technology and 

through interactions with key stakeholders in industry and elsewhere. Overall, these divisions are well 

aligned to contribute to NIST’s maintenance of U.S. leadership in metrology that supports advanced 

optical manufacturing technologies.
18

3

Engineering Physics Division

INTRODUCTION

The mission of the Engineering Physics Division (EPD) is to promote U.S. industrial innovation 

through the development of a high-quality physical measurement infrastructure that is specifically 

relevant to realizing length traceability and that will underpin future electronics. The division has 79 

research staff (including 1 NIST fellow), 95 guest researchers, and 20 students. It is responsible for 

dimensional, nanometer-scale, and surface metrology, accelerometry, acoustic-pressure metrology and 

standards, and advanced electronics manufacturing, testing, and standards. The division is divided into 

five groups: CMOS and Novel Devices, Dimensional Metrology, Nanoelectronics, and Nanoscale 

Metrology, and Surface and Nanostructure Metrology.

ASSESSMENT OF TECHNICAL PROGRAMS

CMOS and Novel Devices

The CMOS and Novel Devices Group has 10 staff scientists, 10 guest researchers, and 6 other 

affiliated staff. The group advances measurement science to accelerate the commercialization and 

manufacture of high-performance and reliable electron devices for the electronics industry by developing 

new characterization techniques, physics-based models, and data analysis methods. The group develops 

the advanced metrology tools to enable quantitative and mechanistic assessment of reliability issues in 

emerging electronic devices. 

Another thrust is to develop new measurements, physical models, and data analysis techniques to 

accelerate the development and commercialization of nanoelectronic-device-based medical technology 

for life sciences and personalized health care. The CMOS and Novel Devices Group has three technical 

programs—reliability for present and future CMOS; back-end-of-line (BEOL) reliability and metrology;

and nanobiotechnology and bioelectronics. The first two programs are closely coupled with the 

semiconductor industry and are important to this multi-trillion-dollar industry.

CMOS reliability has become more challenging to quantify as dimensions have shrunk.

Reliability is an important issue for both consumer and military electronics technology. This PML team 

has made several major technical achievements that address the reliability issue. They include a probe 

station that has been modified to make massively parallel current voltage measurement—this tool allows 

for rapid acquisition of data from which reliability models can be produced; the refinement of a technique 

for measuring low-level defect concentrations produced in the CMOS device during operation; and the

development of a unique high-definition spin resonance tool that allows exploration of the structure of the 

defects that are being measured electronically. The three projects represent important contributions to the 

semiconductor industry, where NIST will continue to play an important role. The challenge is that as 

CMOS scaling comes to its end, the metrology will have to continue to adapt. An exciting application of 

the spin resonant tool will be in biotechnology. An exemplary contribution of the team is that a tool 

originally developed to address semiconductor problems will find its main applications in biotechnology.
19

A second team has focused on BEOL. This team is addressing many of the issues related to 3D 

integration in semiconductor chips. The semiconductor industry is using more chip volume, which results 

in expanding the chip vertically. The CMOS and Novel Devices Group has developed several scanning 

probe and RF techniques for measuring subsurface interfaces and defects and has developed techniques 

for determining the thermal stress in Cu vias. Stress determination is important because 65 percent of 

microelectronic failures are stress-related. Three-dimensional (3D) integration will become ubiquitous as 

the industry pursues multifunctionality in its chip development.

Interaction with the semiconductor industry continues to be important. There may be emerging 

needs for reliability studies and standards in microelectromechanical systems (MEMS) and 

nanoelectromechanical systems (NEMS) technology. NIST needs to continue to track developments in 

this constantly changing environment. A third team addressing bioelectronics is relatively small, with four 

staff members and two guest researchers. However, the technical results are exciting and lay out a

promising biochip development pathway. The researchers have demonstrated biological nanopores on a 

chip that can distinguish the size of proteins electronically. This is an important research direction that is 

being followed worldwide. The biggest challenges in the technology will be developing artificial 

nanopores that can replace the organic pores.

The impressive nanopore work can be used for protein sizing and ultimately could be integrated

with a CMOS-based field-effect transistor (FET). The tip-based electron spin resonance equipment was 

also impressive. This is a unique instrument originally developed for semiconductor characterization, with 

exciting possibilities in PML’s new initiative in physical measurements on living things. The division’s 

effort to create a strategic plan to integrate its biological work into this new initiative is commendable.

Nanoelectronics

The Nanoelectronics Group is composed of 11 research staff members and 25 guest researchers.

The group conducts basic research to advance the optical and electrical measurement science 

infrastructure necessary for innovation in nanoelectronic and thin-film devices and their component 

materials. Within the group are three subgroups that address optical spectroscopy of nanostructures, thinfilm electronics, and nanoelectronic device metrology.

The optical spectroscopy of nanostructures subgroup focuses on Raman spectroscopy to access 

the optoelectronic properties of novel nanomaterials. The focus has been on carbon nanotubes. The

emphasis is shifting to graphene and to dichalcogenides. This subgroup has been instrumental in assessing 

the health and environmental risks of nanomaterials.

The thin-film electronics subgroup develops rigorous measurements and methodology needed for 

continued U.S. leadership in manufacturing and innovation of emerging electronic devices. An example 

of the interdisciplinary work done by the Nanoelectronics Group was the development of a standard 

cleaning technique for graphene. Graphene is particularly difficult to clean because the plasma cleaning 

normally used to remove photoresist and other polymers will destroy graphene films. The thin-film 

electronics subgroup is developing metrology for flexible electronic, high-performance heterojunction 

devices and Li battery technology. An example is the development of internal photoemission 

spectroscopy to quantify band offsets for gate stacks on alternate-channel FETs. These measurements 

utilized a NIST-unique test structure incorporating graphene as an electrically and optically transparent 

electrode.

The nanoelectronic device metrology subgroup seeks to develop measurements that quantify 

physical processes and electronic properties and to manipulate such processes and properties to enable 

innovation through entirely new functionality. An example is the projects in is click chemistry, which 

expands molecular electronics to molecules that do not self-assemble, allowing the build-up of complex 

molecular layers and electrode variety and adding new functionality at well-designed nanometer distances 

and concentrations. Another example is the development of eutectic gallium indium electronic junctions,

which address the difficult problem of contacts to molecular layers.
20

Research in nontraditional materials for the purpose of developing the next generation of 

measurement technologies is a solid rationale for the team’s planned direction. However, it will be 

important that PML avoid duplication of effort conducted by better-funded teams investigating the 

science or technology of these speculative materials systems.

Surface and Nanostructure Metrology

The Surface and Nanostructure Metrology Group consists of 14 research staff and 12 guest 

researchers. The group project teams focus on optical methods for 3D nanostructure metrology;

nanostructured optics and optical surface metrology; forensic topography and surface metrology;

traceable scanning probe nanocharacterization; atom-based metrology; and atomically precise electronic 

devices.

The team investigating optical methods for 3D nanostructure metrology focuses on resolving 

critical issues in deep subwavelength line width and defect metrology for the U.S. semiconductor 

industry. Combining light scattering with algorithms, they are able to extract information from 

subwavelength line widths. They are reporting the world’s smallest multidimensional measurements of 

objects using optical imaging, providing quantitative information from scattered light images at 

resolutions previously thought impossible.

The nanostructured optics and optical surface metrology subgroup is developing innovative 

methods for measurements of ultraprecise flat, spherical, free-form, and nanostructured surfaces and is 

also developing novel nanostructured optics.

The forensic topography and surface metrology subgroup is developing rigorous metrics and 

algorithms for forensic firearm and tool mark identification. This work has produced calibration bullets 

and cartridge cases that serve as laboratory standards. This impressive work illustrates the impact of 

metrology in non-traditional areas. 

The subgroup on traceable scanning probe nano characterization provides fundamental nanoscale

length metrology for such applications as semiconductor manufacturing, optics, photonics, and data 

storage. This group is seeking to understand and characterize tip sample interactions. This is important 

work; it will be interesting to see how the new efforts on atom-based metrology develop. The subgroup 

on atom-based metrology is developing the intrinsic metrology needed to enable atomically precise 

devices at the ultimate scaling limit, applicable to the emerging class of quantum devices.

Dimensional Metrology 

The Dimensional Metrology Group realizes and disseminates the SI unit of length, concentrating 

on dimensional measurements ranging from micrometers to kilometers. The group of 18 full-time staff 

and 2 guest researchers develops and deliver cutting-edge dimensional metrology technologies, including

critical measurement services and standards for industrial manufacturing such as the precise measurement 

of aircraft and automotive parts to ensure proper mating of parts. The group also collaborates on 

dimensional metrology tasks relating to NIST research on measuring discrepancies of the value of the 

universal gravitation constant, G, and evaluation of hip replacement artifacts.

The group has developed the world’s best Fabry-Perot refractometer, which will enable a 

portable, low-cost, and accurate length standard under ambient conditions. The length standard (which, 

since 1983, has been referenced to the speed of light) is currently limited by the accuracy of the air 

wavelength, which in this device is known to 5 in 10−9

due to the water vapor contribution to the 

refractive index of air. Further improvement in this accuracy is anticipated when this contribution is 

corrected for. Because the refractive index in gases depends on pressure, the Fabry-Perot reflectometer 

can also be used to realize a portable primary standard for pressure. An open question remains: How well 

can one maintain long-term stability of the mirror reflectivities under ambient conditions? It might be 
21

worthwhile to consider whether it is possible to scale this down to make a NIST-on–a-Chip device. NISTon-a-Chip is an integrated program to develop and deploy NIST-treaceable measurements and physical 

standards that are deployed in the customer laboratories, factories, devices, and systems; are easily used 

and integrated; provide a wide range of measurements and standards relevant to the particular customer 

needs and applications; and are manufacturable.

The group needs to play an important role in the advanced manufacturing initiative for both longrange and short-range metrology. This would draw the group closer to the other groups in the PML. If not 

currently being done, the group’s researchers could benefit from sabbaticals at customer industries. This 

is particularly relevant for the fast-changing technologies addressed by the group.

Nanoscale Metrology 

The Nanoscale Metrology Group provides advanced measurement science, standards, and 

calibration services for acceleration, shock, and acoustics. The group is an active participant in standards 

committees in the Institute of Electrical and Electronics Engineers (IEEE), International Organization for 

Standardization (ISO), and Semiconductor Equipment and Materials International (SEMI) and also 

provides services for shock measurements for military and sports applications.

The group has revitalized its vibration calibration services activity by opening a state-of- the-art 

primary calibration system to support U.S. calibration laboratories. They have also refocused their 

metrology service efforts on developing primary calibration devices aimed at the rapidly growing, multibillion-dollar MEMS industry for microphones and inertial sensors. 

Hearing loss is a major medical issue for millions of Americans and for veterans who have 

suffered hearing losses as a consequence of combat. The group has created a state-of-the-art capability to 

measure and calibrate the performance of hearing aids with incorporated adaptive filters. They have also 

developed test methods to perform the uncertainty analysis of manikin instrumentation during underwater 

blast testing.

PORTFOLIO OF SCIENTIFIC EXPERTISE

The CMOS and Novel Devices Group is a combination of physicists, biophysicists, and 

engineers. Many of the investigators have industrial experience and are sensitive to the needs and 

limitations of the semiconductor industry; this is especially true for the team doing the reliability work.

The group expertise strongly supports the responsibilities of the group. Considering the new emphasis on 

the measurement of living things, it would be useful for the group to add a protein chemist to work with 

the nanopore team.

The Nanolectronics Group has two Department of Commerce (DOC) silver medal winners and 

has taken on leadership roles in their respective scientific communities.

The Surface and Nanostructure Metrology Group has received several prestigious awards,

including the 2013 research and development (R&D) 100 Award and the 2013 Intel Outstanding 

Researcher in Metrology Award. In addition, the group has been extremely successful in obtaining both 

internal and external funding.

ADEQUACY OF FACILITIES, EQUIPMENT, AND HUMAN RESOURCES

The facilities are more than adequate for the technical program described in the CMOS and novel 

devices area. Some of the equipment developed by the reliability team is unique. The biotechnology team 

collaborates across NIST and with the National Institutes of Health (NIH) for access to biospecific 

facilities. 
22

The facilities are adequate to support the work of the Nanolectronics Group and the Surface and 

Nanostructure Metrology Group. Some of the equipment used by the latter group (particularly for 

dimensional calibrations) is unique and located inside carefully controlled environments.

DISSEMINATION OF OUTPUTS

The Nanolectronics Group has a solid publication record. In addition to publications the Surface 

and Nanostructure Metrology Group provides dimensional calibrations in the range from micrometers to 

0.1 meter.
23

4

Office of Weights and Measures

The Office of Weights and Measures (OWM) has a staff of 20 individuals and implements its 

services through four programs: laws and metric, international legal metrology, legal metrology devices,

and laboratory metrology. 

ASSESSMENT OF TECHNICAL PROGRAMS

Laws Program and Metric Program

The Laws Program provides “technical information, assistance, and training in the areas of 

packaging and labelling, methods of sale, uniform laws on legal metrology, net quantity of contents, price 

verification, and engine fuel quality.”1 The Metric Program “helps implement the national policy to 

establish the SI (international system of units, commonly known as the metric system) as the preferred 

system of units for trade and commerce.”2

To assist U.S. consumers in cost savings, researchers in the Laws Program and the Metrics 

Program have produced a best practices guide for the layout and design of unit price labels. The guide 

assists retailers and governments in improving the accuracy and usability of unit pricing.

The Metric Program presents information to stakeholders through yearly attendance at U.S. 

conferences and provides teacher’s metric kits. The use of social media may provide routes to increase the 

visibility of the OWM’s metric outreach program.

The Metric Program has experienced declines in student participation in outreach events. OWM 

attributes the decline to the decision not to participate in NSF’s Science and Technology Education 

Partnership (STEP) conference in 2014. As a result, OWM decided to attend the 2015 STEP conference 

and plans to attend STEP in 2016.

International Legal Metrology Program 

The International Legal Metrology Program (ILMP) facilitates U.S. participation in the technical 

work of the International Organization of Legal Metrology (OIML), a treaty organization that develops 

voluntary standards intended to be used to harmonize national legislation among member states in areas 

where regulated instruments and measurements are involved.”3

With the publication in April 2015 of its final two sections, International Recommendation OIML 

R 117, Dynamic Measuring Systems for Liquids Other Than Water, is now considered to be the official 

 1 NIST PML, “Laws and Metric Programs,” http://www.nist.gov/pml/wmd/laws/index.cfm, accessed October 

28, 2015. 2 Ibid.

3 NIST PML, “International Legal Metrology Program,” http://www.nist.gov/pml/wmd/ilmg/index.cfm, 

accessed October 30, 2015.
24

international standard for almost all dynamic liquid measuring systems, including those used for fuel 

dispensers, oil pipelines, ship loading, and aircraft fueling.

Legal Metrology Devices Program

The Legal Metrology Devices Program (LMDP) promotes “uniformity at the international, 

federal, state, and local levels in standards and practices for weighing and measuring devices to facilitate 

trade and protect U.S. businesses and citizens.”4

Plug-in electric vehicles make up a growing share of the nation’s vehicles and are prompting 

increased demand for the electrical equivalent of the corner gas station. A standard produced by NIST’s 

U.S. national work group on electric vehicle refueling and submetering was adopted by the National 

Conference on Weights and Measures (NCWM) at its 2015 annual meeting. The standard details how 

customers should be charged and the requirements operators should meet.

The OWM is recognized as the experts in the area of legal metrology and devices and is 

frequently engaged to collaborate with various U.S. national working groups and standards development 

committees.

The OWM’s device-related training has been well received by the states and industry Training 

effectiveness is assessed at the time the training is completed, and the feedback is used to improve the 

training methodology. Long-term training effectiveness is assessed by use of a voluntary follow-up to 

determine how the skills and knowledge acquired are being utilized in the field. It is unclear, however, if 

the long-term effectiveness of the training is being adequately assessed, and OWM needs to place more 

emphasis on this aspect. Examples of methods that could be considered are field audits, practical 

examinations, and partnership agreements.

Laboratory Metrology Program

The laboratory metrology program “provides the basis for ensuring traceability of state weights 

and measures standards to NIST; conducts fundamentals of metrology, mass, volume; and advances mass 

training for metrologists working for the states, for industry, and in other countries.”5

Americans rely on many measurements of mass and volume in their daily lives; the accuracy of 

the devices used in those measurements must be tested at regular intervals. The degree of accuracy 

achieved for these devices depends on the competence of the metrologists who calibrate over 350,000 

measurement standards per year that are then used by weights and measures officials when testing 

measuring instruments.

6

The number of accredited and recognized laboratories has dropped due to inadequate staffing 

succession at the state levels. Accredited laboratories score highest in proficiency examinations, creating 

a challenge for OWM as the number of accredited and recognized state laboratories has dropped due to 

issues with succession planning in some states.

 4 NIST PML, “Legal Metrology Devices Program,” http://www.nist.gov/pml/wmd/lmdg/index.cfm, accessed 

October 28, 2015. 5 NIST PML, “Laboratory Metrology Program,” http://www.nist.gov/pml/wmd/labmetrology/index.cfm, 

accessed October 28, 2015. 6 NIST PML, “OWM Sees Progress in Proficiency Testing,” December 23, 2013, http://www.bldrdoc.gov/pml/

wmd/labmetrology/owm-proficiency-testing-success.cfm.
25

PORTFOLIO OF SCIENTIFIC EXPERTISE

The OWM has a staff of 20 individuals who work as a team. The OWM appears to be adequately 

staffed to achieve its objectives. 

Within the next 5 years approximately 50 percent of the present staff of the OWM will be eligible 

to retire. The organization has recognized the need for succession planning and has a number of 

knowledge transfer systems in place to assist with such planning. Continued vigilance is required to 

ensure there is a transfer of knowledge as retirements take place.

ADEQUACY OF FACILITIES, EQUIPMENT, AND HUMAN RESOURCES

A review of training facilities at NIST determined that the facilities meet the training needs of the 

OWM. The OWM training facility that is used for mass calibrations training could benefit from improved 

storage space.

DISSEMINATION OF OUTPUTS

The OWM does an excellent job of disseminating information through its training program, the 

NIST website, and the publication of technical documents such as handbooks, newsletters, and standard 

operating procedures. The office conducts proficiency testing and a 45-day follow-up survey with 

attendees at the OWM training courses.
26

5

Quantum Measurement Division

INTRODUCTION

The Quantum Measurement Division (QMD) goals and strategic plans are mostly driven by the 

redefinition of the international system of units (SI), specifically by introducing the quantum SI with a 

completion target of 2018. This includes redefinitions of the kilogram, ampere, volt, kelvin, and mole. 

The quantum SI is an approach to implementing the International Committee for Weights and Measures 

(CIPM) recommendation 1 (CI-205). As a result, this division covers an extraordinary range of activities 

in fundamental and applied studies. Fundamental work includes research on single atoms and photons, 

quantum degenerate atomic gases of bosons and fermions, cavity optomechanics, and quantum optics. 

Spectroscopic work, with its long and distinguished history, includes the atomic spectroscopy database, 

and metrology covers aspects that include fundamental measurements of mass and force; basic electrical 

measurements of voltage, ampere, and resistance; and time-synchronized measurements for smart grid 

applications. 

In its plans to physically realize the electrical, mass, and force units, the division focuses on the 

Committee on Data for Science and Technology (CODATA) recommended values of the fundamental 

constants of physics and chemistry. With the increasing reliance on quantum-based measurements, the 

division explores foundational questions directed toward advances in all units, including measurement

schemes beyond the standard quantum limit. Another focus is the dissemination of the primary 

realizations at NIST, illustrated by the mise en pratique efforts to introduce a new realization of mass 

measurement based on electromagnetic levitation.

ASSESSMENT OF TECHNICAL PROGRAMS

Atomic Data and Spectroscopy

The Atomic Spectroscopy Group has an extraordinary record of accomplishments over its 

multidecade history. Calendar years 2013 and 2014 are typical, with 32 and 25 refereed publications 

respectively.

The expansion of astronomical spectroscopy into new wavelength ranges is a great opportunity 

for the group. Mercury cadmium telluride (HgCdTe) detector arrays have opened the infrared (IR), and 

various orbiting facilities have opened the ultraviolet (UV), vacuum ultraviolet (VUV), and x-ray spectra.

Knowledge of the detailed physics and chemistry of the remote universe is gained from spectroscopy. The 

era of exoplanet studies has started, and the era of exobiology will soon follow. 

Although quantum information (QI) processing in the form of a device for factoring large 

numbers is a major goal of QI research, other applications of QI devices may have commercial 

significance much sooner (for example, quantum key distribution schemes and early-stage quantum 

computing products).
27

Experimental Solid State Quantum Information

Within the field of experimental, solid state QI, a competition is under way between trappedatom/ion systems and solid-state (SS) systems for QI processing. Trapped-atom/ion systems offer the 

promise of long coherence times, but SS systems promise greater scalability. This PML group 

investigating experimental solid-state QI is developing an original and promising concept for a SS system 

for QI processing, using electromagnetic separation. Isotopic separation efforts in the group could be 

expanded with a modest investment. Such an expansion would have implications for metrology, e.g.,

improvements in Avogadro’s number, and for technologies such as QI.

Experimental Cold Atoms, Quantum Optics, Nanomechanical Science, and Theory

This is a core enabling component of the PML that provides science drivers and is a powerful 

innovation engine. It also complements the work of the Quantum Physics Division, located in Boulder,

and fits well into PML’s NIST-on-a-Chip activities.

As quantum materials become increasingly important, a central goal of this work is to help shed 

light on these materials by designing and realizing many-body Hamiltonians in ultracold atoms, where 

exquisite control is available. Another motivation for the work is to investigate the use of quantum manybody systems to make new kinds of measurements. These groups are doing experimental and theoretical 

research on ultracold atoms, quantum optics, and nanomechanics that is among the best in the world. The 

researchers produce large amounts of outstanding science and enjoy international recognition. The 

expertise of the experimentalists covers a broad range of areas, including quantum optics and ultracold 

atomic physics. 

The experimental studies of many-body effects in ultracold atomic systems are among the best in 

the world, and the recent test of Bell inequalities, eliminating the remaining loopholes of previous 

experiments, is a telling example of the synergy between different areas of expertise at Gaithersburg and 

JILA, the extraordinarily successful joint institute of the University of Colorado, Boulder, and NIST.

In the relatively new area of optomechanics, a promising direction is the development of new 

bridges between quantum physics and sensor development, with promising applications of optomechanics 

to thermometry. There are also possible applications of single-photon sensing in biological systems.

The theoretical efforts also cover a remarkable range of topics, including many-body physics, 

quantum optics, traditional atomic physics and collision physics, and QI science. The theorists play an 

important role in building bridges between different activities, including between other divisions within 

NIST.

Techniques developed by the PML for precisely placing dopants in silicon may be applicable in 

more general semiconductor fabrication.

The partial relocation of the groups working in this area to the University of Maryland campus 

presents both opportunities and challenges. Opportunities include more access to students, the possibility 

of PML staff seeking funding as University of Maryland adjunct faculty, and additional outreach and 

education through teaching. At the same time, this geographical separation raises the challenge of 

maintaining close collaboration and communication with the Gaithersburg NIST campus.

Fundamental Electrical Measurements, Applied Electrical Metrology, 

Mass and Force, and Synchrometrology

The incremental improvements in the key electrical measurements triangle (voltage, current, and

resistance) are demonstrating continued PML leadership in attempting to increase accuracy while 

reducing uncertainties. The venturing into new materials and the associated quantum phenomena, such as 

the use of graphene for resistance and the Josephson effect for voltage measurements, is focusing on 
28

breakthrough approaches as they become available through new technological developments and 

improved theoretical understanding.

Further refinement of the CODATA constants is critical for continued efforts of the fundamental 

electrical measurements, applied electrical metrology, and mass and force work.

The Applied Electrical Metrology Group is maintaining responsibility for well-established ACDC measurements and is also exploring the AC-DC metrology of the future. A relatively new activity that 

is primarily focused on smart grids addresses issues of synchrophasor measurements, new sensors, and 

the associated problems of interoperability and cybersecurity.

In the mass and force research area the general direction of using quantum physics to devise a 

substitute for artifacts (the watt balance and mise en pratique) is a very promising and much needed 

approach to reducing the cost and increasing the dissemination of calibration references for mass and 

force. This is an impressive collaboration between two formerly independent groups that merged into the 

division. The potential to make key contributions to the next SI revision is significant and remains an 

important focus for NIST. The key challenge may be to achieve the right balance in staffing the various 

efforts, particularly those with a long history of contributions versus emerging ones.

The PML areas of involvement in the smart grid areas are recognized by industry and users as 

needing some breakthroughs to serve the potentially huge domain of future commerce (estimated by the 

Electric Power Research Institute [EPRI/] at almost $500 billion). NIST visibility could be increased by 

engaging various groups in this area beyond those involved in the Smart Grid Interoperability Panel 

(SGIP). The choice of where to concentrate and focus already limited resources remains an issue.

The PML could also focus on smart grid sensors other than phasor measurement units (PMUs),

with a goal of identifying how to help industry obtain more precise, synchronized, and reliable 

measurements. In particular, measurements under dynamically changing conditions are widely untapped 

in the smart grid standardization area, and the PML has an opportunity to position itself as a worldwide 

leader if it tackles this difficult problem. Development of metrology for assessing effectiveness of 

standards for the grid cybersecurity and privacy remains a huge challenge.

The ability of the PML to maintain its leading position in what is one of the oldest metrology 

areas is an accomplishment. 

PORTFOLIO OF SCIENTIFIC EXPERTISE

Through its highly productive scientific exchange, with over 150 journal papers published in 

2014, numerous awards received in the last 5 years, and the hosting of over 90 guest researchers while 

maintaining its own staff of 75, the division remains an essential focal point of the world efforts on 

physical measurement sciences.

ADEQUACY OF FACILITIES, EQUIPMENT, AND HUMAN RESOURCES

Atomic Data and Spectroscopy

The Atomic Spectroscopy Group has unique facilities, including a 2 m normal-incidence 

spectrometer, a vacuum ultraviolet (VUV) spectrometer, grazing-incidence spectrometer, and tunable 

single-frequency lasers. Some of the instruments—for example, the research-grade Fourier transform 

spectrometer (FTS)—are unique in this hemisphere. The shortage of technicians to maintain and upgrade 

the instruments is very serious, even though the FTS and the data center are staffed by excellent scientific 

experts.

The Atomic Spectroscopy Group’s scientific expertise is in urgent need of strengthening due to 

the loss of both electron beam ion trap (EBIT) expertise and expertise on highly ionized atoms (HIAs).
29

The departure and retirement of key atomic spectroscopy staff presents an opportunity to renew the staff 

and to take the group in new directions.

Experimental Solid State Quantum Information

The group has a combination of high-level theoretical and experimental expertise. The 

preparation of isotopically pure silicon films using electromagnetic separation is essential to 

implementation of the SS QI concepts under development by the PML. The productivity of the present 

electromagnetic (for example, mass spectrometer) separation system could be increased with a modest 

investment. The group is providing films for other QI research groups. 

Experimental Cold Atoms, Quantum Optics, Nanomechanical Science, and Theory

The human resources are excellent, with a number of outstanding recent hires. Following the 

move to the Joint Quantum Institute (JQI) on the University of Maryland campus, many staff researchers 

are moving to groups that are more university-like, with three or four graduate students and one or two

postdoctoral researchers, instead of relying more heavily on postdoctoral researchers. One advantage is 

that there is perhaps less pressure to produce fast results with students, who, in contrast to postdoctoral

researchers, are under less pressure to accumulate a portfolio of results within a couple of years and may

focus more on challenging long-term projects.

A substantial fraction of the activities of this group has been relocated to, or is in the process of 

moving to, the JQI. The new Joint Center for Quantum Information and Computer Science (QuICS), also 

located on the University of Maryland campus, is also a joint venture with the NIST Information 

Technology Laboratory (ITL); this further strengthens intra-NIST collaboration as well as collaboration 

with the University of Maryland.

Opportunities associated with the move to the JQI and the QuICS on the University of Maryland 

campus include the benefits of interactions with university faculty, researchers, and students; the 

possibility of attracting more students to NIST projects; and the opening of new funding avenues. There 

are also opportunities to disseminate results through teaching. 

Fundamental Electrical Measurements, Applied Electrical Metrology, Mass and Force

NIST’s ability to maintain high-quality facilities using limited human resources and a relatively 

limited budget is quite impressive. An example of the PML’s ability to maintain its complex facilities is 

the effort that identified issues with the 4.45 MN force standard machine and helped to expedite its 

reconditioning. The machine was built several decades ago, and the PML group performed precise 

modeling of the deterioration phenomena associated with the material galling that developed in key 

structural components within the stainless steel weight stack.

In the Fundamental Electrical Measurements Group and Applied Electrical Metrology Group, 

some of the efforts are covered by one or two people only, so staffing may have to be reassessed.

DISSEMINATION OF OUTPUTS

Atomic Data and Spectroscopy

The web-based Atomic Spectra Database (ASD) is a great success. The group has continued to 

update and modernize the ASD interface to make it increasingly useful.
30

Spectroscopy will continue to be an important diagnostic for many industrial processes.

Experimental Solid State Quantum Information

The PML research in this area is highly visible through publications and conference 

presentations.

The need for isotopically pure silicon from multiple research areas is becoming increasingly 

clear. A modest investment in the small electromagnetic (mass spectrometer) isotope separation system 

would be valuable. The isotopically pure silicon would be more readily available to internal NIST users 

and, to the extent that it could be shared with researchers outside NIST, could be used to foster 

collaborations. It is not necessary to scale up to the large gas centrifuge separation scale that supplies the 

German Physikalisch-Technische Bundesanstalt (PTB) with macroscopic artifacts of isotopically pure 

silicon.

Experimental Cold Atoms, Quantum Optics, Nanomechanical Science, and Theory

The results of the research in this area are disseminated in leading journals and at conferences 

with invited papers and through college courses at the University of Maryland. 

In collaboration with JQI and QuICS, teaching presents an opportunity to disseminate results and 

train future scientists. JILA has a long and successful tradition along these lines, and a similar outcome 

can be expected from JQI as it further establishes itself.

Fundamental Electrical Measurements, Applied Electrical Metrology, Mass and Force

The dissemination of primary units realizations is an extremely important mission and needs to be 

supported, with the focus on making the secondary units cheaper but with even more manageable 

uncertainties. The educational and training efforts for the customers who use the standards are also 

important.

The PML has provided leadership in smart grid technologies, mainly in synchrophasor 

measurements and interoperability of metering devices. The PML can leverage its work in the timing 

standards, atomic clock in a chip, and NIST-on-a-Chip, to develop inexpensive standards for reliable,

time-synchronized and interoperable and cybersecure metering standards. For smart grid applications, a 

timing accuracy of 1 microsecond is acceptable. While the PML has engaged a small section of industry, 

it is important to increase that engagement.

The dissemination of the work in the new area of smart grid technologies may pose some 

challenges in balancing the metrology and standards mission of NIST with industrial and commercial 

interests.
31

6

Quantum Physics Division

ASSESSMENT OF TECHNICAL PROGRAMS

The Quantum Physics Division (QPD) has a diverse range of programs, including 

nanotechnology and biological physics, but it continues its firm and unified base in metrology, 

appropriate for the programs’ association with NIST. New advances in measurement science are at the 

heart of many major scientific advances, and JILA, the joint institute between NIST and the University of 

Colorado, Boulder (and, therefore, the Quantum Physics Division), is widely recognized as one of the 

leading research and training organizations in atomic, molecular, and optical (AMO) physics and closely 

related areas. JILA has been ranked as the nation’s top AMO graduate program for decades. JILA 

scientists are responsible for a long list of breakthroughs in AMO physics, such as the world’s first BoseEinstein condensate, first Fermi condensate, first self-referenced laser frequency comb, first evaporative 

cooling of molecules, first quantum degenerate gas of polar molecules, and first cooling to the quantum 

ground state of a macroscopic object (the last-named was accomplished in collaboration with other NIST 

scientists).

Work on self-referenced femtosecond laser frequency combs was initially pursued as a tool to 

improve optical frequency standards (atomic clocks), but now laser frequency combs have become one of 

the most powerful and versatile research and precision metrology tools since the invention of the laser. 

Laser frequency combs are routinely used across PML laboratories for research and metrology in such 

areas as remote sensing, chemical analysis and quantification, generation of precision RF and microwave 

signals, medical diagnostics, length standards, atomic clocks, and references for exoplanet identification 

and characterization, with new applications appearing continuously. Frequency combs are also ubiquitous 

in the research laboratories of universities and in national laboratories.

The interplay with and impact on applied physics is also apparent. Improved optical frequency

standards will find use in fields that traditionally rely on precision timing (navigation, electronics, 

communications, and spectroscopy), but in more extreme ways. Such possibilities might include deep 

space travel and optical-based circuitry and ultraprecision timing for science experiments (e.g., at 

accelerator centers). The TFD has sent a frequency-comb system to the McDonald Observatory in Texas 

to aid in the search for exoplanets.

Quantum degenerate gases include Bose-Einstein condensate, Fermi condensates, and molecular 

gases. In addition to providing a unique laboratory for fundamental physics, scientists across NIST use 

quantum degenerate gases for quantum information (QI) processing research, quantum simulation, and 

ultrahigh vacuum standards, with new applications continually evolving.

Division scientists demonstrated cooling to the quantum ground state of a macroscopic object.

This system is a promising candidate for quantum information processing, and for ultrasensitive 

transducers.

Another area of research is observation of spin exchanges in ultracold potassium-rubidium (KRb) 

molecules inside an optical lattice (a crystal of light formed by overlapping laser beams). In solid 

materials, such spin exchanges are the building blocks of advanced materials and exotic behavior. 

Observation of spin swapping could have an impact on future research in such diverse areas as hightemperature superconductivity, energy transport through biomolecules and in chemical reactions, 
32

spintronics (a new kind of microelectronics), and the physics of liquids and solids. The work on spin 

exchange of ultracold molecules is a new testing ground, enabled by tools that have been developed at the 

division. It will address fundamental questions of molecule–molecule interactions and can be used as a 

quantum simulator of many-body spin dynamics.

The group of Eric Cornell is using trapped molecular ions to search for a possible electric dipole 

moment of the electron. This experiment is one of several other ongoing efforts worldwide. The potential 

for non-point structure of the electron has deep implications for fundamental physics, cosmology, the 

apparent imbalance between matter and antimatter, and many other issues. The Cornell team has pushed 

in the 10−28 uncertainty range, where possible EDM (electric dipole moment of the electron) effects may 

be just detectable and is poised to push into the unexplored 10−30 range.

There is a strong theory effort in the division. One of the more exciting areas is understanding the 

realization of quantum Hall states via synthetic gauge fields generated by a spatially dependent optical 

coupling between internal states of the atoms. One current topic is how to suppress or control collisional 

relaxation decoherence as well as alternative ways of generating strong Abelian and non-Abelian gauge 

fields.

Stable laser systems have long been defined by John L. Hall and coworkers. The early days of 

this work used, for example, locking to the Lamb dip; the work has progressed far beyond the early 

stages. Work is being conducted on unique ultrastable laser technologies, including the development of an 

ultrastable reference cavity comprising a monolithic silicon crystal with unique end mirrors and on 

reducing sensitivity to cavity perturbations. This is used to lock the laser while the signal from an atomic 

clock is being acquired. Such a device is often called a flywheel because it provides excellent short-term 

stability to the laser. This work is important in a variety of fields, including experimental relativity and

the laser gyro.

Cold atom and stable laser physics is an important area of research. While there are some earlyknown quantum many-body phenomena with clear impacts (for example, quantum magnetism and

superconductivity), the biggest impacts are likely to come from phenomena not yet known or observed. 

The division strives to play a leadership role in this new frontier, in both experiment and theory, while 

still leveraging research and measurements using the many important single-body (individual) quantum 

phenomena.

A fascinating development is the creation of a unitary quantum converter that can interconvert 

microwave and visible radiation. This advance, while limited by the need for extreme temperatures (40

mK), could eventually have wide-ranging implications for the Internet and other applications. Scientific 

applications that can eventually benefit from it include clock-signal distribution and QI transfer. As noted 

in a 2014 commentary,

1 “The potential to transfer QI between optical and microwave photons is 

especially exciting to the QI processing community. Superconducting microwave circuits have shown 

great promise for quantum computing, while quantum optics is better at transmission and quantum 

measurements—combining the two would vastly expand our ability to process and communicate 

information at the quantum level for computing and security purposes.” This effort is at the cutting edge,

and it is not known where it will go, but the potential seems large. It is an example of the kind of work 

one hopes for from JILA.

Biological physics in the division has had a varied path, including the development of 

technologies to probe the real-time dynamics and kinetics of large, single biological molecules such as 

proteins, enzymes, and nucleic acids, to better understand normal physiology and disease processes. 

These are large areas of science being conducted worldwide. There are technical barriers that can arise

and that need innovative measurement science, to which the division has been a contributor. Historically 

there are examples of the application of measurement science within the field of biological physics, one 

of which is described below, but there are new capabilities emerging that will broaden the scope if further 

encouraged.

 1 M. Tsang, 2014, Microwave photonics: Optomechanics sets the beat, Nature Physics 10:245-246.
33

As a historical example in biological physics, targeted chemotherapy often exploits a genetically 

engineered monoclonal antibody (mAb) that is chemically attached to an agent that can kill tumor cells. 

Monoclonal antibodies are designed to attach to specific antigens (e.g., proteins) that are predominantly 

found on the surfaces of malignant cells, and mAb’s can be engineered to bind to them. Once research 

determines that a certain cell-surface molecule indicates cancer, then mAb’s can be designed to target that 

molecule and hence the cell that it is on. One way to target therapy is to conjugate radioactive atoms to 

the mAb’s, using the radiation to treat the tumors. This radioimmunotherapy received FDA marketing 

approval in 2009. However, before FDA could approve the marketing of radioactive materials (e.g., 

yttrium-90) there needed to be a measurement system in place to ensure that the intended dose of 

radiation was delivered. The PML Radiation Physics Division was instrumental in getting this done, 

holding workshops so that the relevant stakeholders agreed on what procedures were needed, and 

providing an anchor in the quality system—a yttrium-90 radioactivity standard solution. This is an 

excellent example of how research crosscutting physics and biology is being carried out at NIST. 

Another example in biological physics has been the development of the world’s most stable 

atomic force microscope (AFM) for biophysical applications, such as exploring the folding landscape of 

biological macromolecules in solution or in biological membranes. Because the measurements are in 

aqueous environments at physiologically relevant temperatures, the 100- to 1,000-fold gain is relevant for 

the biology. While the division’s AFM technology is currently aimed at following the complex behavior 

of proteins and nucleic acids in real-world biological systems, it is also available for a broad range of 

physical measurements. It is significant that one of the leading laboratories is seeking to duplicate the 

instrument, and the division is helping it to do so.

AFMs are also being developed for the study of structure–energy relationships in biological 

macromolecules and membranes. When biological macromolecules are synthesized, they are linear 

polymers that must fold to make specific compact structures before they can function in cells. There has 

been limited work to optimize AFM methods to follow the energetics and intermediate states of protein 

folding. This has presented an opportunity for a laboratory focused on metrology to pick apart the 

technique, identify the weaknesses, and fix them. The result is an orders-of-magnitude improvement in 

stability and sensitivity that opens up new capabilities and is likely to allow new explorations of protein 

folding, a missing conceptual link in the expression of genetic information. In the fields of biological 

membranes and macromolecular folding, energy landscapes can now be explored as a set of equilibrium 

measurements that were inconceivable before the JILA advances. The current results on the folding of a 

membrane protein are particularly interesting and are unmatched by those in any other laboratory in the 

world. 

The world’s fastest system for measuring and separating individual living cells with unique 

properties revealed by ultrafast optical studies has been demonstrated for activities such as quickly 

identifying algal cells with the highest biofuel production and rapidly identifying optimal fluorescent 

proteins used to monitor real-time processes in living cells. Practical uses of biological systems are often 

assisted by finding the optimal organisms in a diverse population, so this technology will find important 

applications.

PORTFOLIO OF SCIENTIFIC EXPERTISE

In terms of its core strengths, the QPD includes an elite collection of scientists—so elite that it is 

a constant problem to protect the Fellows from recruitment by other organizations. Unfortunately, the 

salary of NIST employees is often not able to compete with salaries at academic institutions.

Along with recruitment by other organizations will be the problem of replacing the senior JILA 

Fellows as they retire. The division is moving strongly into research and measurements on quantum 

many-body phenomena as the key thrust of the second century of quantum mechanics. Single-body 

(individual) quantum phenomena have been enormously successful and powerful.
34

The division does not seem to have a consistent and clear approach to the use of intellectual 

property. In some fields, the use of a patent by a research organization can be to facilitate new companies 

that can be protected in their exploitation of the kinds of technology developed at the division. It appears 

that there has been no consistent view, and that the expertise to guide a technology transfer effort is not in 

place. Division investigators are, understandably, confused, asking, “Are we patenting this year?” An 

organized position needs to be thought through for the future—either intellectual property is useful and 

important or not, in the areas represented. A serious effort is a large expense, so the division will need to 

seek support from PML if the decision is to protect the intellectual property.

ADEQUACY OF FACILITIES, EQUIPMENT, AND HUMAN RESOURCES

JILA has a very slow turnover rate, perhaps because it recruits excellent faculty and make them 

happy. Faculty hired more than a decade ago are still referred to as new, and the slow turnover makes the 

initiation of new areas, such as biological physics, challenging. There will probably be, it seems, a tension 

between maintaining current directions and creating new ones. The following findings confirm those of 

the previous (2010) review of the division2

:

• The new JILA X-Wing provided the space needed to expand present crowded laboratories 

and make vibration-free areas and, hopefully, clean rooms available for ultrafast and other 

experiments. The JILA shops provide service that is unmatched in pure university 

environments in the design and construction of various types of mechanical and electronic 

equipment, and it is critical that they be maintained at that high level.

• The current size of JILA is nearly optimal, given expectations for future financial resources 

and space and in recognition of the challenges of maintaining a coherent organization as the 

organization’s size increases. JILA does not expect to grow appreciably in the foreseeable 

future. Instead, it will focus on improving the balance of various research areas through 

replacements as fellows retire or otherwise leave JILA.

DISSEMINATION OF OUTPUTS

The following findings confirm those of the previous (2010) review of the division3

:

• The impact of the QPD is outstanding as measured against its stated goal and mission of 

making important advances at the frontiers of science that enable future precision 

measurement technology and producing graduates who form a talented pool of scientists who 

are now dispersed throughout the NIST laboratories and elsewhere. These researchers are 

also having significant impact through applications of their technology outside NIST—for 

example, in sensitive, high-resolution frequency comb spectroscopy for trace detection and 

molecular fingerprinting and in the development of technology for multiplexed lowtemperature detector arrays for astronomy.

• The division is a premier laboratory that favorably competes, in most of the fields of research 

that it pursues, with the best academic and federal research institutions in the world, and the 

graduate school of the University of Colorado was recently ranked in a national rating as 

number one in atomic physics. The laser frequency comb work and the cold atom and now 

the new cold molecule research are among the best in the world. The division has attracted 

 2

 National Research Council, Assessment of the National Institute of Standards and Technology Physics 

Laboratory: Fiscal Year 2010, The National Academies Press, Washington, D.C., p. 52. 3 Ibid., p. 50.
35

applicants with competing offers from top-five U.S. institutions in areas identified for 

expansion, such as biological physics and nanoscale physics.

JILA alumni have started about a dozen high-tech companies in such areas as optical 

components, medical diagnostics, and gravity meters. These companies provide innovative technologies 

and good jobs, commensurate with the NIST mission to facilitate economic growth and new technologies. 

JILA alumni are key scientific and innovation leaders in industry laboratories, in universities, and in 

national laboratories (beyond NIST). They contribute broadly to U.S. economic growth and technology 

development, and they expand the active network of collaborators for NIST.

CONCLUSION

The Quantum Physics Division has had a spectacular run of success over the past 20 years, and 

long-range planning will be needed to guide continued success. The move into quantum many-body 

phenomena with strong theoretical support is important so that the division will remain at the frontier of 

quantum physics. However, the role that quantum-nano biological physics plays in the division needs to 

be carefully considered. The biological physics effort presently has very little quantum physics. While the 

current faculty are outstanding, biological physics will need additional hires if it is to become on par with 

the level of effort of other areas in this division.

Given the promising developments such as those described above, it seems that some expansion

is warranted, subject to the reality of budget constraints.
36

7

Radiation Physics Division

The primary mission focus of the Radiation Physics Division (RPD) is ionizing radiation physics 

metrology. As part of NIST, a national metrology institute (NMI), it is required to establish, disseminate, 

and ensure the proper utilization of standards in regard to all aspects of ionizing radiation. In addition to 

the responsibility to maintain state-of-the-art radiation physics metrology, there is a recurring requirement 

to develop novel standards to meet current and future needs as the state of radiologic sciences advances.

The division prioritizes its efforts based on input from a variety of outside stakeholders, which 

include the Council on Ionizing Radiation Measurements and Standards (CIRMS). CIRMS is an 

independent, nonprofit council that draws together experts involved in all aspects of ionizing radiation to 

discuss, review, and assess developments and needs in this field.

1 Drawing on expertise from government 

and national laboratories, agencies, and departments, from the academic community, and from industry, 

CIRMS issues periodic reports on the needs in ionizing radiation measurements and standards.

2 Such 

needs are delineated in measurement program descriptions (MPD’s), which indicate the objective, state 

background information, define needed action items, and estimate resource requirements in terms of 

personnel and facilities. Through dialog at CIRMS meetings and workshops, the appropriate 

subcommittees (currently industrial applications and effects, medical, and homeland security/radiation 

protection) independently determine the needs in their respective communities.

In addition, there is organized input from professional groups such as the Radiological Society of 

North America (RSNA); Society of Nuclear Medicine and Molecular Imaging (SNMMI); and the 

American Association of Physicists in Medicine (AAPM). These groups provide clinical input, a realworld perspective that helps maintain relevance of division activities from a clinical and scientific 

perspective. There is additional strong input from industry, with direct interaction that impacts the quality 

control and regulatory compliance of American business and supports international leadership in radiation 

treatment machines, scanners, radioactivity measurement devices, and dosimeters. Through 

intragovernment committees, there is direct input to specialized radiation and regulatory needs that 

positively impacts mandated responsibilities of the Food and Drug Administration (FDA), Nuclear 

Regulatory Commission, Department of Energy (DOE), Department of Homeland Security (DHS), and 

the National Institutes of Health, among other agencies.

The RPD is also responsible for maintaining liaison with international agencies that have parallel 

radiation metrology functions in other parts of the world. There is key exchange of both information and 

standards with groups from the United Kingdom, Japan, and Germany and from other official government 

bodies on both a routine and emergency basis, to ensure global standardization and uniformity of 

measurement and reporting of quantitative radiologic activities and radiation use. 

Within the RPD there are three groups: the Dosimetry Group; the Neutron Physics Group, and the 

Radioactivity Group, each with clearly defined core functions.

 1 Council on Ionizing Radiation Measurements and Standards, “Welcome,” http://www.cirms.org, accessed 

November 24, 2015. 2 The latest needs report was updated following the CIRMS 2015 meeting and can be accessed at the CIRMS 

website (http://www.cirms.org).
37

The Dosimetry Group performs work in the following areas: radiation source standardization, 

chemical interaction studies and reporting, dose from medical imaging procedures, radiation protection 

dosimetry for the nuclear engineering field, international liaison, determination of biological effects of 

ionizing irradiation, science and technology of radiation for the DHS, high-dose calibrations, gamma- and 

x-ray calibrations, and brachytherapy calibrations. A key mission of the Dosimetry Group is to develop 

and maintain national air kerma and absorbed dose standards (kV and MV x rays, Co-60 and Cs-137 

gamma rays, and Sr-90 and Kr-85 beta beams) based on the derived SI unit—the gray—for homeland 

security, medical, radiation processing, and radiation-protection applications.

The Neutron Physics Group performs work in the following areas: fundamental neutron physics, 

neutron interferometry, neutron source calibration, neutron imaging, neutron instrumentation calibrations, 

neutron instrument development, and special calibrations.

The Radioactivity Group performs work in the following areas: basic radionuclide metrology, 

low-level radionuclide metrology, imaging studies and standards, calibration services, measurement 

quality assurance, development of nuclear forensic standards and methods, investigation in international 

and national developments in technology, and production of standard reference materials (SRMs). The 

key mission of the Radioactivity Group is to develop and maintain state-of-the-art high- and low-level 

radioactivity detection methodology, including gamma, beta, and alpha counting and spectroscopic 

capabilities, often based on first-principles methodology that directly measures key radioactive emissions 

by multiple cross checks and approaches in order to maximize confidence in assay accuracy. The group is 

also required to develop relevant standards and methods of assay for common radionuclides used in 

industry and medicine, including calibration services for radioactivity dosimeters utilized in nuclear 

medicine. The group defines protocols for radioactivity measurement on the national and international 

level. In addition, other government agencies such as the Nuclear Regulatory Commission and the FDA 

may mandate linking of radioactivity measurements to NIST-maintained standards.

ASSESSMENT OF TECHNICAL PROGRAMS

Dosimetry Group

Among the recent accomplishments of the Dosimetry Group are the 320-kV W-anode x-ray tube 

replacement, establishment of an air-kerma standard for electronic brachytherapy using a miniature x-ray 

tube (50 kV, 300 μA), development of the Lamperti free-air chamber, and implementation of a new Co60 therapy-level calibration facility with state-of-the-art data acquisition and operating capabilities.

The quality of the work by the group is excellent. It demonstrated competence in maintaining 

existing radiation dosimetry standards and in developing new ones as needed by the user community. In 

2015, a new Co-60 irradiator is being installed to replace an older unit. This work is expected to improve 

the ability to maintain a number of dosimetric standards essential to the radiation oncology community.

According to the Task Group report 51, issued by the American Association of Physicists in Medicine

(AAPM),

3 therapeutic-level clinical x-ray dosimetric standards are based on Co-60 sources.

The work in the Dosimetry Group appears to be largely in services rather than innovative 

research. The group does have a list of potential research projects that can be pursued if funding is 

available.

Research in advanced computing (such as Monte Carlo simulations) could enhance existing 

capabilities in radiation measurement and dosimetry. It would be advantageous to strengthen the training 

program that involves students and postdoctoral researchers in each of the critical standards activities and 

foster a program to share equipment and facilities with users at national laboratories and universities. 

 3 Dosimetry of interstitial brachytherapy sources, AAPM Task Group Report 51, reprinted from Medica Physica

22(2).
38

Neutron Physics Group

In addition to its core activities, there is a unique basic-research program in the fundamental 

properties of the neutron. This program is synergistic with the core elements, because the stringent 

demands of the physics measurements call for a steadily advancing art of calibration and instrumentation.

The fundamental neutron science program is carried out at the NIST Center for Neutron Research 

(NCNR) and in Building 245. With the new guide hall now in full operation, neutron beam intensities are 

up by a factor of 5 or more. The additional capacity in flux and in the number of available ports represents 

a substantial improvement. The guide hall is the world’s most modern and places the neutron program in 

a class with other world-leading reactor neutron programs, such as the one at the Institut Laue-Langevin 

in Grenoble, the Gatchina reactor in St. Petersburg, Russia, and the high-flux isotope reactor (HFIR) at 

Oak Ridge. 

The basic neutron physics research program by PML scientists at the NCNR has led to advances 

in metrology. For example, the continuing work to refine the lifetime of the free neutron has led to a 

recent major advance in neutron flux determination at the 0.1 percent level. This makes possible a new 

level of precision in neutron cross sections.

The Neutron Physics Group standardizes neutron sources (252Cf, AmBe, etc.) for users around the 

world in industry, government, and academia. The RaBe photoneutron source at NIST, called NBS-1, is 

the national reference standard, which has been determined to 0.85 percent.

The Mn bath method is used at NIST and at four other laboratories around the world to calibrate 

source strengths relative to NBS-1. The Bureau International des Poids et Mesures (BIPM) discontinued 

its calibration service and sent its three standard sources to NBS-1, and all were found to agree well 

within the combined uncertainties.

The group also provides spectral reference measurements from a room constructed with boronloaded walls having a very low return. A scintillation and He-3-based detector has been constructed as a 

new methodology for higher-energy neutron spectra.

Neutron imaging is another important service provided by the group. It has wide application, in 

industry particularly; new technologies such as fuel-cell and battery development need it. In the imaging 

program there are opportunities for new advances in technology, and NIST is an international leader in 

this area. Phase-contrast methods are used for high-definition density measurement. A unique new 

instrument that uses Wolter optics to obtain micrometer spatial resolution is under construction and in 

limited operation; full capability will be in operation by 2018.

The Neutron Physics Group, in cooperation with external collaborators, has been successful in 

obtaining DOE support for a strong program in fundamental physics. Within the constraints of its limited 

budget, the Neutron Physics Group has managed to develop new technology in support of the core 

program—for example, a scintillator-proportional counter array for the measurement of high-energy 

neutron spectra such as cosmic-ray secondaries.

Radioactivity Group 

The work of the Radioactivity Group appears to be largely in services rather than innovative 

research. The group has a list of potential research projects that can be pursued if funding is available.

Some of the recent accomplishments of the Radioactivity Group include maintaining continuous 

standardization of approximately 30 distinct radionuclides as primary standards linked to nuclear 

medicine. A suitable standard for accurate measure of the alpha emitter radium-223, a recently introduced 

therapeutic radionuclide for prostate cancer treatment, is under development. The group is collaborating 

with professional societies such as the AAPM in the development and publication of 90Y protocols for 

radiation brachytherapy. The group’s new measurement of the half-life of 209Po has resulted in substantial 

revision of the accepted half-life.
39

Dose calibrators are used in nuclear medicine tens of thousands of times each day in the United

States, and they depend on NIST-determined calibration factors for more than 20 different radionuclides. 

Some recent examples include 18F, 68Ge, 111In, 123I, 125I, 133Ba, 177Lu, and, as mentioned, 223Ra. Future 

work focuses on 64Cu and 227Th.

The quality of the work by the Radioactivity Group is excellent. They demonstrated competence 

in maintaining existing radionuclide standards and in developing new ones identified by the user 

community. In addition, as part of a grant from the DHS, they have developed key nuclear forensic 

standards to be used for investigations of stolen radioactive materials destined for use in radiologic 

devices such as dirty bombs. 

PORTFOLIO OF SCIENTIFIC EXPERTISE

Most of the counting equipment is state-of-the-art, and the specialized expertise of the staff is 

related to the unique experience needed to maintain the standards. Positions of staff members and 

technicians in the Radioactivity Group who have resigned or retired recently were either filled or 

reprogrammed. However, if these actions have not resulted in a sufficient number of technicians, this 

creates an undesirable situation whereby Ph.D.-level staff are required to perform routine sample 

preparation, including weighing and pipetting of radioactive solutions, packaging, and shipment. The time 

of these highly trained and dedicated individuals would be better utilized for research into state-of-the-art 

issues such as radioactivity metrology and dissemination of knowledge on proper use of modern 

equipment for accurate assay.

Some of the unique equipment can be operated optimally only by a highly expert single 

individual, and there is relatively little time to train more junior staff in the proper use of certain 

specialized equipment and counting devices. A stronger training program that involves students and 

postdoctoral researchers in each of the critical standards activities would help fill the personnel gap that 

now exists, and it would provide intelligent, willing workers who learn on the job in the unique NIST 

environment. Another area to explore could be alliances with medical physics training programs at 

regional universities, to provide internships of varying length that would be sponsored through NIST 

internal resources. Budget plans that project the expansion of such programs could be considered for the 

future. 

Management can further encourage the pursuit of cutting-edge radioactivity research projects 

with external funding from DHS, NIH, DOE, and private-sector industry. An example would be the 

development of positron emission tomography (PET) and computed tomography (CT) and PET/MRI 

devices in Gaithersburg as part of a secondary standards laboratory devoted to nuclear medicine 

quantitation. One element of this is the growing emphasis on the theranostics, in which the same 

radionuclide may be used at the tracer level for dosimetry and detection and, by scaling up to 

radiotherapeutic doses, could be used for therapy. There will be important standardization issues in the 

radioactivity measurement as well as tissue dosimetry as the range of dose is expanded over orders of 

magnitude. A strong presence in this field of the experienced NIST metrology experts would likely give 

U.S. industry and medicine an important competitive advantage. 

Strategic projects that align closely with the priority areas of the PML—in particular, medical 

imaging—would seem to be a natural component of such an approach, and there is already a good basis 

for this in terms of expertise and facilities. Enhanced research in areas of collaboration where NIST 

excels, such as advanced computing (for example, in Monte Carlo simulations), would augment existing 

capabilities in radiation measurement and detection.
40

ADEQUACY OF FACILITIES, EQUIPMENT, AND HUMAN RESOURCES

Most of the equipment is state-of-the-art, and staff expertise is related to unique experience 

needed to maintain the standards. However, in the laboratories of Building 245, where most of the 

radionuclide standards are prepared for shipment, the rooms are old and lacking in proper heating and 

ventilation, with consequent inadequate control of humidity and temperature. Neutron source 

standardization is carried out in a number of shielded, below-grade laboratories in Building 245. Water 

intrusion during heavy rains has become an issue, because the building is no longer watertight. These 

events are, at a minimum, distractions to overburdened scientists and in some cases have threatened to 

flood sources under test. Dispersal of the source material is remotely possible, but the immediate concern 

is damage and loss of calibration traceability. Repair and renovation of building 245 are urgently needed. 

These conditions, along with the requirement for researchers to perform technician chores due to a lack of 

manpower and technical support, are severely compromising the ability of the staff to perform key tasks.

The neutron metrology staff has decreased in number to a level causing concern, and efforts are needed to 

add technical support in this area.

The resilience of the core program against the loss of a single individual is no longer assured.

Many core activities are supported by a single scientist, without the assistance of a technician. Scientists 

are spending time on functions that are inappropriate and wasteful for highly qualified personnel. They 

must handle packing and shipping, compliance issues, contract generation, purchasing, and budget 

analysis. This is having an increasingly corrosive effect on the entire core metrology function in the 

division, and especially on the neutron physics program.

The fundamental neutron research program has a high profile in the U.S. nuclear physics 

program, as delineated in the long-range plans periodically released under the auspices of DOE and NSF, 

most recently in 2015. This profile has allowed NIST to recruit outstanding talent for the neutron 

program. These individuals are also responsible for the neutron metrology services, and they carry them 

out with the same goal of leadership and excellence. 

Nuclear medicine is more and more reliant on a combination (fusion) of instruments whereby a 

CT scanner and a positron emission tomograph are combined into a single gantry for imaging use. This 

approach to nuclear medicine is essentially quantitative; accuracy and precision of measurement would be 

greatly benefited by involvement of the Radioactivity Group in developing standardized phantoms and 

appropriate radioactivity standards. As part of the future relevance of NIST to medical practice, a PET/CT 

scanner was purchased and installed in the Radioactivity Group. Unfortunately, funding was insufficient 

for a proper maintenance contract, and at the time of this review, the PET/CT had been out of action for 

several weeks. Attention to proper maintenance and support for such a valuable program is important.

Management could further encourage conjoint programs to share equipment and facilities with users at 

national laboratories and universities, to enlist whenever possible outside facilities to bolster the NIST 

mission.

The positions of staff members in the Dosimetry Group who have retired recently have been 

filled or reprogrammed. However, some of the critical standards for diagnostic x rays, Cs-137/Co-60, and 

high-dose industrial applications are maintained by a single staff member. At least one critical staff 

member is close to retirement, and if the position is not filled with a qualified individual, the quality of 

the program will suffer.

DISSEMINATION OF OUTPUTS

Members of the Dosimetry Group are active in various professional societies—for example, the 

AAPM, the American National Standards Institute (ANSI), and the Health Physics Society (HPS)—

which helps to disseminate the work at NIST. The group also interacts with CIRMS, DOE, and the FDA. 

Members of the Dosimetry Group also publish in journals The group supports three AAPM-accredited
41

dosimetry calibration laboratories as well as other secondary calibration laboratories through its 

calibration services.

For the Neutron Physics Group, the program output is disseminated in many ways and is 

effective. In addition to published research papers and conference presentations, the calibrations and the 

distribution of standard reference materials are universally recognizable products. Many guest researchers 

come to NIST to take part in the fundamental neutron physics program and to collaborate with personnel 

in the Radiation Physics Division. There is also abundant cross-fertilization between disciplines because 

so many disparate sciences are practiced at the NCNR. An example is the development of the small-angle 

neutron scattering (SANS) device at the NCNR, with polarized neutrons for the study of magnetic 

ordering in materials. A major step toward this new capability came from the helium-3 polarizers and 

analyzers first devised for fundamental neutron physics by an RPD scientist. 

The Radioactivity Group does an excellent job in disseminating its work through interactions 

with CIRMS, AAPM, SNMMI, DOE and FDA and in providing calibration standards for many common 

radionuclides used in nuclear medicine. In some cases they interact with groups who provide a secondary 

standard service that is traceable back to NIST. The advantage of this approach is that a very a large 

demand for radioactivity measurement standards can be met by expanding through secondary standards 

that will still relate to the NIST-prepared primary standards. 

Members of the Radioactivity Group are active in various professional societies such as AAPM, 

SNMMI, and HPS, which helps disseminate the work of NIST, and they also publish journal papers. 

These services include the dissemination of technical reports such as Technical report series 454, Quality 

Assurance for Radioactivity Measurement in Nuclear Medicine.

Unfortunately, there are examples where dissemination of proper radioactivity standards has not 

been able to proceed as rapidly as required owing to a lack of funds. Because medical imaging and 

nuclear medicine increasingly depend on short-lived radionuclides such as F-18 (110-minute half-life) or 

C-11 (20-minute half-life) there is recognition that specialized and accurately calibrated detection devices 

need to be sent between institutions in the United States to serve as the standard of measurement, since it 

is physically impossible to ship the radionuclides themselves.

One such device uses the triple-to-double coincidence ratio (TDCR) method. As explained on the 

website of the Laboratoire National Henri Becquerel,2

. . . TDCR is an absolute activity measurement method specially developed for pure beta- and pure 

EC-emitters activity determination, in which the detection efficiency is calculated from a physical 

and statistical model of the photon distribution emitted by the scintillating source. As the signals 

delivered by the photodetectors are affected by the thermal noise of the photocathode, a 

coincidence method is used to remove that noise. There is not enough information in a twophotodetector system to determine the experimental detection efficiency without an additional 

reference source. The TDCR method uses a three-photomultiplier detector, allowing the 

observation of 3 kinds of double coincidences (2 photodetectors) and triple coincidences (3 

photodetectors).

The Portable TDCR is a portable version of one of the primary measurement systems for activity 

measurements of beta emitters, positron emitters, and electron-capture decay radionuclides. There is 

concern that, because of the lack of manpower for calibration and testing of these TDCR devices at NIST 

within the Radioactivity group, U.S. hospitals have difficulty taking proper advantage of these specialized 

devices for on-site measurement to establish proper radioactivity standards. Meanwhile, foreign standards 

laboratories such as the Physikalisch-Technische Bundesanstalt (PTB), the European Association of 

Nuclear Medicine (EANM), and others, funded through a European Union investment in metrology, have 

working instruments.
42

8

Sensor Science Division

INTRODUCTION

The Sensor Science Division (SSD) of the PML conducts an extremely broad set of technical

activities. The division creates and produces devices and articles as primary and secondary standards for

dissemination, creates standards, and does fundamental science in a diverse set of technical fields. These

fields include optical, temperature, and pressure measurement, as well as imaging and flow. Size scales

range from a few atom widths to many meters and system complexity ranges from photonic devices to

satellites and smokestacks. The division comprises a division office (6 staff and 3 associates), overseeing

the work of six groups: Thermodynamic Metrology (16 staff and 3 associates), Fluid Metrology (10 staff

and 1 associate), Optical Radiation (16 staff and 3 associates), Infrared Technology (10 staff and 9

associates), Laser Applications (9 staff and 1 associate), and Ultraviolet Radiation (10 staff and 1

associate). However, the review of the division was conducted along the lines of programs, as carried out

in various facilities. The high degree of collaboration within the division results in the fact that a given

program is almost always supported by staff from more than one group; however, it was not always clear

which groups, and how many staff from each, supported each program. The panel therefore conducted its

assessment on the basis of the facilities it had the opportunity to observe, and the thematically coherent

programs conducted within them, rather than attempting to assess the groups themselves.

ASSESSMENT OF TECHNICAL PROGRAMS

Vision Science Laboratory

The research work presented in the vision science laboratory is mature, and its results are ready to 

be introduced as a worldwide standard. The team working in this area is exploring solid-state lighting 

from a psychological point of view. The results of this study are important because they will impact the 

replacement rate of incandescent lighting. Lighting comprises a significant fraction of the nation’s total 

electricity usage, and solid-state lighting has the potential to reduce electricity usage for lighting by a 

factor of 10 or more. One big difference between incandescent and solid-state lighting is the ability to 

control the color of the light. Currently, solid-state lighting is specified by the light output (lumens) and 

the color temperature. The vision science team has added a third factor, chromaticity or tint, and has 

found that people prefer a pinkish tint. The desired tint depends to some extent on the cultural background 

of the subject. This finding is likely to broaden the appeal of solid-state lighting, accelerating the 

transition, saving energy, and reducing CO2 emissions.
43

Optical Properties of Materials and Spectroradiometry

The research in the areas of optical properties of materials and spectroradiometry appears to 

involve excellent personnel and equipment with accuracy over a prodigious spectral range from 4 nm to 

100 μm. This team conducts a significant portion of the division’s measurements for customers and has a 

wide and deep outreach program, participating in standards organizations, training personnel from other 

national measurement laboratories (NMLs), conducting short courses, performing phantom development, 

and generating publications.

The reflection measurements are being automated to save customers time and money and to 

reduce the workload of highly trained personnel, allowing them to pursue more creative activities. 

The reflection measurements were not conducted or stored in a clean and dry area. This could be

acceptable if it were an experimental setup or if the measurements did not require the accuracy of samples 

free of a small amount of dust.

Photonic Sensors and Standards

An overarching theme at the division is the development and deployment of NIST-traceable 

measurements and standards that are reliably produced in low size, weight, and power (low-SWaP); lowcost (low enough to enable broad customer deployment, or even embedded applications), integrated 

packages producing one or more measurements. At an institutional level, this initiative is known as NISTon-a-Chip, where the overall goal is to develop and deploy SI-traceable measurements and physical 

standards that are deployed in the customer’s environment. The desired attributes are usability (small size, 

low power, rugged, easily integrated and operated); flexibility (broad range of SI-traceable standards,

possibly including a few to many measurements from an single small and affordable package); and 

manufacturable (low cost for broad deployment or acceptable cost for high-value applications). Within 

the SSD, there are numerous examples of this theme in development. An example of particular 

significance is the development of a dynamic pressure standard based on wavelength modulation 

spectroscopy. Two significant aspects of this project are these: (1) dynamic pressure measurements are 

particularly difficult and inaccurate using current approaches, most of which are designed to measure 

static, or slowly varying pressures, so that some important, highly dynamic situations, such as shocks, are 

measured with significant inaccuracy; and (2) there are many extremely important application areas that 

require relatively inexpensive, broadly deployed (or especially embedded) measurement systems. A 

prominent example with both high economic and policy impact is the phenomenon of traumatic brain 

injury occurring in sports and in military combat. The potential for sensors in this context is recognized 

by the PML, and that application is guiding some aspects of the current program. As the research 

progresses, it will be important to assure that measurement of acceleration and “jerk “(the third derivative 

of distance with respect to time) is being considered, with the objective of developing an integrated 

accelerometer/dynamic pressure sensor.

Low-Background Infrared Facility

The low-background infrared (LBIR) facility specializes in low-power infrared measurements 

with wavelengths from 2 to 30 μm, and it does so at a physical scale sufficient to test actual sensors used 

in astrophysics and missile defense. The LBIR receives significant support from the Missile Defense 

Agency (MDA) and is used extensively by some of the MDA’s major contractors. The NIST traceability 

of radiometric measurements is one of the singularly defensible (technically) aspects of MDA’s programs 

of record, which have undergone significant programmatic upheavals. 

The LBIR’s strong customer focus leads to several issues and uncertainties concerning its future.

The underlying research program, focusing on high-sensitivity electrical substitution radiometers, solid-
44

state trap detectors, fluid bath cryogenic vacuum blackbody sources, and carbon nanotube sources and 

detectors, does not seem as closely coupled to customer needs; evidence of such coupling was not 

presented during the assessment. The LBIR needs to ensure that one of the MDA contractors, Johns 

Hopkins University (JHU) Applied Physics Laboratory, is not essentially duplicating the NIST capability. 

The extreme politicization of missile defense over the past 6 years makes the MDA program highly 

unstable and has led in the recent past to significant management and programmatic upheavals. The LBIR 

needs to undertake scenario-based planning to seek a broader customer base, aligning the research 

program to the needs of other customers, such as the National Aeronautics and Space Administration 

(NASA) and to minimize disruption that might occur with a significant, unpredictable change in MDA 

support.

SIRCUS/Satellite Sensor Calibration/Ocean Color/Space Weather

This program and its primary facility, the spectral irradiance and radiance responsivity 

calibrations using uniform sources (SIRCUS) facility, underpin optical metrology in terms of power, 

irradiance, and radiance for a broad range of important measurement systems with high operational and 

scientific significance, such as weather satellites, land and ocean color sensing, stratospheric aerosols, 

Earth’s radiation budget, and corresponding ground truth artifacts. The range of customers is impressive: 

NASA, NOAA, the National Geospatial-Intelligence Agency (NGA), and the Department of Defense 

(DoD). 

Given the ever-increasing importance of hyperspectral measurements and imaging, the increasing 

emphasis of SIRCUS on calibration methods and standards for such systems is admirable. 

One possible caution concerns the increasing emphasis on lower-cost, lower-SWaP sensors for 

future satellite systems, following the National Polar-orbiting Operational Environmental Satellite System

(NPOESS) programmatic debacle, and the later cancellation of the DoD-focused Defense Weather 

Satellite System (DWSS). The SIRCUS team could explore (and perhaps partner in development of

smaller radiometric sensor systems for satellites. It is possible that the upcoming NASA preaerosol, 

clouds, and ocean ecosystem (PACE) mission, if awarded competitively, could provide an opportunity for 

disruptive developments in radiometers that would effectively displace the Visible Infrared Imaging 

Radiometer Suite (VIIRS). At a minimum, the division could prepare to calibrate much smaller 

radiometers for its customers.

Pressure and Vacuum Measurement Program

These efforts are important and will particularly impact semiconductor manufacturing, where 

molecular-level control of pure environments is critical. Photonics measurement will replace, among 

other measurement methods, a 3-m mercury column and will enable a route to faster measurement that 

can be more easily deployed to a field environment by means of handheld devices usable at room 

temperature. This effort to integrate the standard and the sensor is consistent with the priorities of NISTon-a-Chip. There are also significant efforts to automate calibration and testing to improve service for 

customers, including reduced turnaround time and lower cost.

Members of the team are amongst the best in the world in their activities to reinvent pressure 

measurement, having won several awards within their communities, published papers, and pursued 

numerous patents. Overall, the efforts of this program are commendable and on a good trajectory.
45

Fluid and Flow Metrology

This program has provided best-in-the-world capability to realize flow measurement over 11 

decades for gas flow and 5 decades for liquid flow. The team has won several awards and honors recently 

for its efforts in these areas. A notable effort is the characterization of hydrogen flowmeters for highpressure refueling of hydrogen-powered vehicles with reduced uncertainty and rapid response times. A 

portable field test standard has been developed for use at refueling stations. This work is impressive and 

important as the world seeks alternatives to fossil fuels. Other flow metrology efforts include use of 

microwave resonances to measure large volumes and efforts to develop methods for measuring 

microscale flows. 

Acknowledging the challenge of quantifying small-scale flows, it would be worthwhile for the 

team to continue developing other noninvasive and in-line ways to determine microflows that can be 

readily integrated into devices. The development of measurement methods for multiphase flows is also 

worthwhile. These are challenging areas that are becoming increasingly important with the growth and 

use of hydraulic fracturing methods. 

Smokestack Simulator Laboratory

As the world places a higher cost on emissions of CO2 from coal-burning power plants, the need 

for more accurate measurement of these emissions increases. In response to this need, a new, first-in theworld, 1:10 scale model of a swirling smokestack is being built and tested. The challenges lie in the very 

rapid, turbulent, 3D, swirling nature of flows in smokestacks, and in the need to accurately measure 

transport of CO2 within this type of flow, in very harsh environments. The PML is at the forefront in 

developing tools and calibrations to address these needs, emphasizing accurate, systematic, and 

appropriate use of long-wavelength acoustic flowmeters. Though still in early stages, these efforts are 

excellent and hold significant promise for aiding national efforts to limit environmental release of 

greenhouse gases. 

Synchrotron Ultraviolet Radiation Facility

The Synchrotron Ultraviolet Radiation Facility (SURF III) is a nationally unique facility 

providing NIST traceability for (most) solar-observing and space sensors operating in the UV and 

extreme UV part of the spectrum. These instruments underpin the current understanding of solar 

variability and its potential contribution to global climate change. SURF III also underpins the current 

understanding of parts of space weather, and its potential impact on critical national and international 

infrastructure in space. Its customer set includes NASA, NOAA, and the DoD. The facility is under active 

development to provide NIST-traceable irradiance measurements from 2 nm to 500 nm with less than 1 

percent absolute uncertainty (current capability is 4 to 400 nm). The facility also calibrates approximately 

25 photodiodes per year to disseminate the radiometric scale over SURF’s spectral regime. 

The quality of the work done at SURF supports broad international collaboration, despite the 

relative decrepitude of the radiation physics building (building 245). Notwithstanding the challenges of 

operating in this building, this was the one facility within the SSD that was not meeting the standards for 

neatness and order that characterized the rest of the facilities visited; this building needs attention.

Conclusion

The division’s general strategy of moving metrology from pristine laboratory contexts to more 

complicated real-world environments associated with applications is commendable. The division appears 
46

well coupled to the communities it serves and strives to solve their problems with the goal of better, safer,

and more useful products. The emphasis on low-cost, portable, photonic, and potentially embedded 

standards is particularly relevant and consistent with the theme NIST-on-a-Chip.

While the overarching strategy was well articulated, the division did not describe plans for some 

of the projects, particularly those that are funded externally; those working on internally funded initiatives 

seemed to have more concrete plans.

PORTFOLIO OF SCIENTIFIC EXPERTISE

The SSD is a large division created several years ago by combining a number of disparate 

activities with multiple areas of expertise and capabilities. The division is now synergistically very 

productive; this is a testament to good management. It is a division of outstanding and very capable 

people who cover a large spectrum of technology and science. 

Despite the impressive breadth of technical areas, the SSD appears to be leaders in all their 

activities, in measurement and, in many cases, the underlying science. They participate in and lead 

national and international standards committees in their fields of interest, and they have generated

numerous publications and patents. Many of the world’s other leading standards laboratories send staff to 

be trained at this division and ask for their staff to visit and transfer technology. The division is asked for 

help by many leading organizations with exacting requirements for measurement accuracy such as 

NASA, DOE, and DoD laboratories.

The staff seemed very knowledgeable in the domains related to their activities, in terms of their 

specific work and in terms of worldwide scientific and technological developments. Many of the staff are 

leaders in their fields. There is a general expectation of excellence and objectivity and very good 

alignment with the public service mission of NIST. The division conducts a large fraction of the NIST 

calibrations and dissemination of secondary standards, but staff expressed little objection to doing routine 

measurements or supplying multiple samples. In fact, members of the division expressed pride in the 

number of samples they produced and expressed desire to find ways to make them cheaper and to find 

ways to automate the measurements for faster and better service. 

The division did not describe a strategy for maintaining its spectrum of excellence and diversity 

(age, gender, ethnicity, and expertise) of human capital to maintain the division’s preeminence over the 

long term. Flat funding exacerbates this problem, but addressing the problem is very important and 

worthy of effort and a definitive plan. In particular, the presumption that a practical solution will be 

achieved by a likely delay in senior staff retirement is neither constructive nor forward-looking, even if 

that pattern is based on experience. Very few people maintain high creativity for decades, and simply 

delimiting the desired spectrum of staff attributes by length of experience seems to fall short of desired 

management principles in an institution with a critical mission.

ADEQUACY OF FACILITIES, EQUIPMENT, AND HUMAN RESOURCES

The division appears to have excellent facilities, and the work spaces are generally well 

maintained. The one exception was the SURF area. Division management acknowledged that this 

building needs a refurbishment, but much can be done to improve the situation in the short term with a 

clean-up and attention to making the area safer.

Quality Management System in the Sensor Science Division

Support of the QMS in the Sensor Science Division is viewed as supportive of the overall PML 

mission, and not a system populated by checkers. The PML is to be congratulated on this approach. The
47

NIST PML mission of maintaining and improving the U.S. (and, through consultative committees, the 

international) SI system of physical measurements requires exacting standards and the implementation of 

quality control throughout its divisions. The standing of the PML as gauged by international comparisons, 

customer feedback, and interaction with stakeholders speaks to the effectiveness of the overall quality 

management system (QMS). It appears that the QMS is implemented in a way that maximizes efficiency 

and minimizes staff requirements. In other contexts, including those of the International Organization for 

Standardization (ISO) and national standard regimes, such as AS9100, quality assurance is envisioned as 

requiring a completely parallel staff system, which is frequently viewed by customer-facing staff as 

redundant, threatening, and contributing to overhead. The PML apparently implements its QMS using 

staff who themselves have customer-facing and customer-supporting responsibilities This leads to a 

constructive team dynamic and endows the staff implementing the QMS with moral authority when 

inevitable problems arise. QMS in the Sensor Science Division is viewed as supportive of the PML

mission and not a system populated by checkers. The PML is to be congratulated on this approach.
48

9

Time and Frequency Division

INTRODUCTION

The Time and Frequency Division (TFD) is located in Boulder, Colorado. The division consists 

of approximately 125 technical personnel, including federal employees and NIST associates. The majority 

of the staff works on the NIST Boulder campus. One TFD staff member has an appointments in both the 

Time and Frequency Division and the Quantum Physics Division. The TFD carries out an extensive 

technical program in virtually all areas of time and frequency. While the majority of division funding 

comes directly from the NIST appropriation, a significant amount of its support is received from the DoD

and members of the national intelligence community. The breadth, depth, and impact of this program are 

unmatched by any similar foreign metrology organization.

ASSESSMENT OF TECHNICAL PROGRAMS

The current TFD technical program is well aligned with the strategic goals of the organization.

These goals have three interrelated components: realization of the official U.S. time scale (Atomic 

Standards Group), dissemination of time and frequency information (Time and Frequency Services 

Group), and conduct of the research that underpins the quality of products today and ensures advances of 

these products in the future (Ion Storage, Optical Frequency Measurements, and Atomic Devices and 

Instrumentation groups) This is a solid strategic approach. Its results have produced state-of-the-art time 

and frequency products today with a firm foundation for future improvements in place. The TFD effort 

expended in developing and addressing a strategic perspective is in keeping with recommendations 

provided by the 2010 National Research Council review of the NIST Physics Laboratory.

1 The

recommendation calling for more thorough strategic planning has been addressed in an excellent manner 

by the TFD. 

The quality of TFD products employed in realizing official U.S. time and frequency is 

outstanding. Central to this is the national frequency standard NIST-F2. This standard, based on a cesium 

atom hyperfine transition, is internationally recognized as the most precise and accurate national 

standard2 in the world. Consistent with a technical program that addresses current and future time and 

frequency needs, NIST-F2 is the cryogenic extension of the NIST-F1 standard. The latter standard was 

the first United States standard to employ cold atoms in a cesium fountain, while NIST-F2 now places the 

microwave interaction region in a cryogenic environment, dramatically reducing the frequency 

uncertainties resulting from the blackbody radiation of the standard housing. The TFD accomplishment of 

developing the cryogenic, cesium fountain clock as the national standard of the United States has 

improved national and international timekeeping. 

 1 National Research Council, 2010, Assessment of the National Institute of Standards and Technology Physics 

Laboratory: Fiscal Year 2010, The National Academies Press, Washington, D.C., Chapter 1. 2 T.P. Heavner, E.A. Donley, F. Levi, G. Costanzo, T.E. Parker, J.H. Shirley, N. Ashby, S.E. Barlow, and S.R. 

Jefferts, 2014, First accuracy evaluation of NIST-F2, Metrologia 51(174).
49

The actual U.S. timescale is maintained by an ensemble of about 10 hydrogen masers whose 

frequencies are periodically steered by NIST-F2 and NIST-F1. This information is a major contributor to 

coordinated universal time (UTC), the international time scale maintained by the BIPM,

3 the French 

equivalent of NIST. Complementing the time scale is the exceptional progress the TFD has shown in the 

development of ultrastable radio-frequency (RF)/microwave signals. Employing laser comb signals, TFD 

laboratories have improved the stability of microwave signals from 100 to 10,000 beyond that obtained 

from other methods of generation. This is reflective of a technical program producing products of the 

highest quality.

The TFD has accomplished its goal of disseminating its time and frequency information in an 

exemplary manner. The TFD is a major contributor to national and international time scales. Beyond this, 

the TFD actively distributes its expertise domestically and internationally, providing training

opportunities to guest researchers, maintaining a strong commitment to publication and conference 

participation, and conducting a variety of instructional events.

Underlying time scale maintenance and dissemination is the research portion of the TFD 

technical program. The program seeks to advance the state of the art to meet the needs of stakeholders in 

the future and to improve the quality of current time and frequency products. An example of applied 

research improving products in the near term is the effort to operate a new primary frequency standard 

(such as NIST-F1 or -F2) in a nearly continuous manner. This new approach to maintaining a time scale 

allows a single-hydrogen maser to be almost continuously steered by the primary standard, replacing the 

10-maser ensemble that is only periodically adjusted by information from NIST-F2. The result will be a 

more stable time scale realized in a more cost-effective manner.

Looking further into the future, TFD laboratories are exploring new standards based on optical 

transitions. With operating frequencies approximately 100,000 greater than those of microwave transition 

standards, optical standards are already orders of magnitude more stable and accurate than their 

microwave analogs. The new generation of standards can be divided into two general categories based on 

atoms and ions. The atomic standard being investigated employs optical transitions in ytterbium (Yb)

atoms. Currently the TFD Yb standard is the most stable in the world. Its stability is on the order of 2 ×

10−18. This can be compared to the accuracy and ultimate stability of NIST-F2, whose accuracy reaches 

approximately 1 × 10−16. The ion standards employ either single mercury (Hg) or aluminum (Al) ions held 

in electromagnetic traps. Again, these devices have accuracies in the upper 10−18 range. The TFD research 

into trapped ion standards improved the performance of these devices and provided a foundation for 

significant accomplishments in the area of QI and processing. Evidence of the significance of 

accomplishments in this area is the Nobel prize awarded to David Wineland, a TFD staff member. A 

further accomplishment of the research effort is the recognition and demonstration that combining optical 

standards with optical frequency combs allows relating their frequencies in an extremely precise manner 

to lower, electronically accessible values that are more easily manipulated. The research aspects of the 

TFB technical program are also at the state of the art internationally.

Members of the TFD continue to work at the forefront of optical frequency combs. One area of 

particular accomplishment focuses on generation of microwave signals with ultralow phase noise and 

timing jitter through photodetection of optical frequency combs. In this so-called optical frequency 

division process, the already low optical phase noise associated with individual comb lines that are 

referenced to ultrastable resonators and atomic frequency references is divided down by the ratio of the 

optical to microwave frequency. Through optical frequency division TFD scientists have now 

demonstrated generation of 10-GHz microwave signals with the best low-frequency phase noise ever 

reported, substantially below what is available with the best electronic oscillators. This work is pushing 

technological performance and is advancing scientific understanding. One notable example involves the 

understanding of shot noise, a fundamental noise process in photodetection that arises because photons 

arrive as discrete and randomly spaced energy packets. A standard expression for shot noise has been 

 3 Bureau International des Poids et Mesures, Time Department, “Staff of the BIPM Time Department,”

http://www.bipm.org/en/bipm/tai/members.html, accessed September 14, 2015.
50

known for decades and is widely applied. TFD researchers showed that when short pulse laser sources 

such as those from optical frequency combs are used for microwave generation, the standard shot noise 

formula associated with continuous-wave laser excitation is modified, allowing generation of microwave 

signals with phase noise and timing jitter below the limit that the conventional shot noise formula would 

predict.

Another notable area of accomplishment within the last 5 years is in the generation of optical 

frequency combs through nonlinear wave mixing in optical microresonators. Such microcombs offer 

dramatic size reduction compared to frequency combs derived from mode-locked lasers, thereby opening 

the possibility of applications beyond specialized laboratory settings. TFD researchers have developed 

new methods for fabricating high-quality-factor optical microresonators at low cost and high speed and 

have used these microresonators as a platform for investigating comb generation physics and noise 

processes. The TFD is among about a half dozen of the most active and visible groups worldwide, and it 

is at or very near the top of this group in terms of application of microcombs for optical metrology and 

low-phase-noise signal generation. The TFD accomplishments in optical frequency division for lowphase-noise microwave generation and in microcombs have attracted a series of grants from other 

government agencies.

There are also interactions with companies that want to commercialize the compact Ca clock 

developed at the TFD. This system would serve as an ultrastable microwave source for a variety of 

applications, including very long baseline telescopes and radar detection of slow-moving objects. Clockbased relativistic geodesy is an intriguing possibility that challenges contemporary physics to find 

applications where gravitational potential is the critical quantity.

TFD activities on chip-scale atomic clocks, which originated a little more than a decade ago 

under funding from the Defense Advanced Research Projects Agency (DARPA), are a major success 

story. By employing modern microfabrication techniques and miniature lasers, the NIST group was the 

first to realize an atomic clock at chip scale. This effort was relatively new at the time of its inception but 

has now grown into a subject pursued by many groups worldwide. A commercial version of the chipscale atomic clock was introduced in 2011 by a U.S. company, Symmetricon (now Microsemi), and is 

being used for applications with modest timing requirements (modest in comparison to NIST’s state-ofthe-art frequency standards) such as telecommunications networks, GPS receivers, and seismic 

exploration. The development of the chip-scale atomic clock has impact from both a research and a 

dissemination perspective.

The frontier of trapped ion physics and technology is defined by Wineland’s Ion Storage Group 

in the TFD. Indeed, the early days of atomic cooling were pioneered by, for example, Wineland and 

nearly simultaneously by Dehmelt at the University of Washington. They pioneered various aspects of 

laser cooling of atoms, and they are theoretically and experimentally showing how the kinetic energy of a 

collection of resonant absorbers can be reduced by irradiating these absorbers with near-resonant 

electromagnetic radiation. Their process is closely related to anti-Stokes spontaneous Raman scattering.

At present the use of ion traps is ubiquitous in many areas of physics, including quantum computers and 

atom-field matter interactions.

Over the last few years, work on chip-scale atomic sensors has been broadened to include other 

sensing applications. In one example, TFD researchers demonstrated the first chip-scale magnetometer.

This device, which operates near room temperature, achieved performance equivalent to that of SQUID, 

which requires cooling to below 1 K. TFD scientists partnered with medical researchers to demonstrate 

sensing of weak biomagnetic fields, enabling, for example, precision measurements of fetal heart activity 

without the need to implant electrodes. New programs aimed at using atomic sensors for sensing of other 

fundamental quantities (for example. length and temperature) are now under way as part of the NIST-ona-Chip initiative.

The dramatic progress in laboratory demonstrations of optical clocks, both in the TFD and in the 

Quantum Physics Division, brings them to the point where they demonstrate world-record stability of 2 × 

10−18, nearly two orders of magnitude better than the NIST-F2 cesium clock (currently at ~1 × 10−16

accuracy). Several different matter systems for optical clocks are being explored (for example, various 
51

ions in the TFD Ion Storage Group, Yb atoms in the TFD Optical Frequency Measurements Group, and 

Sr atoms in the Quantum Physics Division at JILA). Optical clock technology shows promise to take over 

as the new primary frequency standard in the years ahead. The opportunity and challenges confronting 

NIST researchers and researchers worldwide is to continue this progress, to develop optical clocks to the 

maturity needed, and to chart the evolution of optical clock technology to become a primary standard.

The performance of the best optical clocks is now at a level where even minute changes in the 

gravitational field, such as those associated with a few centimeters change in elevation, become 

observable. On the one hand, this brings new opportunities for applying such clocks to sensing. On the 

other hand, it raises the question whether optical clocks are nearing their accuracy limit, since with further 

improvements they may become dominated by the local microgravitational environment.

TFD research related to the NIST-on-a-Chip initiative appears to center on incorporation of 

multiple atomic sensors, such as those introduced in the previous, highly successful chip-scale atomic 

clock work, interconnected via on-chip waveguides with in-plane light propagation. The general idea of 

scaling to a larger number of sensors and exploiting waveguide photonics to enable more sophisticated 

device architectures is appealing. Further development of their roadmap for this work will be beneficial.

PORTFOLIO OF SCIENTIFIC EXPERTISE

The scientific and technical expertise resident in the TFD is outstanding. Developing this 

internationally recognized level of excellence is a significant accomplishment of the TFD. The 

achievements outlined in the preceding section result directly from the excellence of the scientific 

expertise resident in the division. This excellence is further confirmed by the numerous awards TFD staff 

members have received, including a 2012 Nobel prize in physics. Additionally, TFD staff members have 

received multiple external awards, such as the Benjamin Franklin Medal from the Franklin Institute, the 

Rank Foundation Prize, the IEEE Sensor Technical Achievement Award for chip-scale devices, the IEEE 

Rabi Awards for time-scale establishment and oscillator development, and the National Conference of 

Standards Laboratories International (NCSLI) Wildhack Award for remote time-measurement services.

Staff members have also received many NIST and DOC awards. These include multiple Arthur S. 

Flemming Awards, Gold and Silver and Bronze DOC awards, and NIST’s Rabinow, Condon, and 

Slichter awards. The award subjects span a wide variety of TFD areas of investigation and effort. Within 

NIST a prestigious position is that of fellow, a rank achieved by only 2 percent of staff members. While

the TFD represents 2 percent of the NIST technical staff, fellows within the TFD comprise 10 percent of 

the NIST population of Fellows. 

The TFD scientific expertise evident during the review was primarily of an experimental nature.

One consideration is whether the theoretical expertise actually resident within the TFD is sufficient to 

support the experimental efforts into the future. As stabilities and accuracies of frequency standards 

continue to improve, strong theoretical support will be required. Of course, NIST staff does collaborate 

closely with staff of JILA, where theoretical expertise resides. The adequacy of this expertise and 

ensuring continuing close interaction deserves ongoing attention.

With the current excellence of TFD scientific expertise comes the challenge of maintaining the 

same high level into the future. This will require ongoing effort on the part of NIST researchers and 

management. Not surprisingly, many current junior staff members have outstanding qualifications.

Confirming this are the multiple forms of recognition already received. Examples include the

International Union of Pure and Applied Physics (IUPAP), the Young Scientist Award, European 

Frequency and Time Forum Young Scientist Awards, and the Humboldt Foundation’s Fyodor Lynen 

Research Fellowship. This bodes well for ongoing excellence of the scientific expertise within the TFD.
52

ADEQUACY OF FACILITIES, EQUIPMENT, AND HUMAN RESOURCES

Most of the buildings on the NIST Boulder campus are about 60 years old. These older buildings 

do not provide the environmental controls (for example, temperature and humidity) necessary for modern 

precision measurement central to the TFD mission. The new precision measurement laboratory building, 

which was completed in 2012, represents a major improvement. The laboratories visited are well 

equipped. Such performance improvements in physical facility are essential to the division’s ability to 

maintain its scientific leadership. Challenges associated with shortage of meeting and collaboration space 

have also been voiced by TFD staff.

The unique facilities associated with the TFD provide remarkable synergy, enabling research that 

could be accomplished at few other institutions. As one example, research of optical frequency combs can 

draw on cold atom and ion frequency standards programs and use these highly stabilized frequency 

references for stabilization of the comb. Optical frequency comb research can also access maser signals 

associated with the U.S. primary clock for stabilization or measurement of the comb repetition rate. 

Conversely, the highly stabilized comb enables comparison of optical clocks based on different matter 

systems.

Of approximately 130 TFD personnel, 42 percent were NIST permanent employees. The 

remaining 58 percent were guest researchers, consisting of graduate students, postdoctoral researchers, 

contractors, and foreign visitors. A benefit of the large pool of guest researchers is that the division work 

force is being constantly refreshed. The guest researchers also provide a pool from which permanent hires 

can be made when openings arise. As noted above, several of the more junior TFD researchers have won 

awards from external bodies. Such recognitions provide evidence of the TFD’s ability to attract excellent 

new talent to its workforce.

Because of its unique strengths and capabilities, the TFD has enjoyed continued success in 

attracting funding from other government agencies. This has allowed it to broaden its research portfolio in 

important ways beyond its core activities. Some of this work has been sufficiently successful that it led to 

some of the division’s highest impact programs—for example, chip-scale atomic clocks, quantum 

information (QI) processing, and low phase noise signal generation from optical frequency combs. 

TFD staff have voiced concerns that there are major institutional challenges associated with 

administrative processing in accepting funding from other agencies.

Concerns were also raised with respect to an onerous procurement process with substantial 

delays. Several staff spoke of a high overhead rate on capital equipment; they suggested that this makes 

acquisition of expensive equipment very difficult.

DISSEMINATION OF OUTPUTS

The products of the TFD program are various and are disseminated in many ways. The division 

distributes not only scientific expertise and findings but also technologies for measuring and maintaining 

precise time and frequency; it disseminates internationally as well precise time and frequency 

information. The dissemination efforts and their resulting impacts are outstanding, meeting the needs of 

both internal and external stakeholders. While there are opportunities and a limited number of areas of 

potential improvement, the levels of excellence in all aspects of product dissemination are at the state of 

the art, displaying international leadership.

The dissemination of scientific expertise and products proceeds along two primary paths. Fiftyeight percent of the division staff is composed of guest researchers, primarily graduate students, 

postdoctoral fellows, and visiting researchers. The ratio of permanent to guest staff is the result of a 

strategy that seeks to disseminate scientific expertise to scientists throughout their careers. The ongoing 

training of nearly 60 researchers in a field as specialized as the measurement and maintenance of 

extraordinarily precise time and frequency is an accomplishment worthy of note. The scale of such efforts 

may be compared to those of similar organizations such as BIPM. One of the BIPM’s responsibilities is 
53

the maintenance of international time through the collection of information from timekeeping institutions 

around the world. Its time department lists 8 permanent staff members4 compared to the approximately 50 

permanent NIST staff members in the Time and Frequency Division. By inference, the BIPM’s outreach 

through visiting researchers will in no way match that of the TFD.

Beyond direct training, the TFD publishes the results of its scientific investigations regularly, and 

its staff participates in numerous domestic and international conferences. Over the period 2010 through 

2014 the TFD averaged 58 publications per year. In 2014 the BIPM Time Department produced 12 

publications.

5 In 2014 also, the time and frequency department of the German equivalent of the NIST, the 

Physikalisch-Technische Bundesanstalt, produced 5 publications.

6 Similarly, in 2012, the Division of 

Time and Frequency of the Chinese National Institute for Metrology produced 10 publications.

7 In terms 

of its publications, the TFD is therefore a unique institution on an international scale.

In the dissemination of time and frequency technology the TFD has excelled in a number of 

areas. The most accurate primary atomic frequency standard contributing to UTC is the cooled cesium 

fountain clock, NIST-F2. The scientific and technical excellence embodied in this device set the state of 

the art in 2009 when it was brought into operation, with continuing improvement through 2014, at which 

point it became the official primary frequency standard of the United States,

8 along with the continuing 

NIST-F1. To distribute the unique expertise within this standard, a copy was provided to the Italian 

National Metrology Laboratory, Istituto Nazionale di Ricerca Metrologica, in 2009.

9 Today this is the 

second-most-accurate standard contributing to UTC. The research that NIST conducts currently in the 

field of optical frequency standards will result in the next generation of primary national standards.

Eventually this will significantly improve the performance of the UTC time scale. Progress in this area is 

disseminated through publications and participation in international conferences.

Continuing its efforts related to chip-scale devices, the TFD is applying its expertise related to 

small gas cell frequency standards to a new generation of extremely compact magnetometers. Such 

devices have the potential to make laboratory-quality magnetic field measurements available to a broad 

range of applications in various environments. Progress in this field is conveyed to the international 

community through publications.

10,11,12 Of particular note is the introduction of such technology to the 

 4 Ibid.

5 Bureau International des Poids et Mesures, Time Department, Director’s Report on the Activity and 

Management of the International Bureau of Weights and Measures (January 1, 2014–December 31, 2014) 

Supplement: Time Department, http://www.bipm.org/en/publications/directors-report/, accessed September 14, 

2015.6 Physikalisch-Technische Bundesanstalt, Time and Frequency Department Publications, 

http://u99132.bs.ptb.de/cms/de/ptb/fachabteilungen/abt4/fb-44/44-literatur.html, accessed September 14, 2015. 7 Chinese National Institute of Metrology, Division of Time and Frequency Publication Summary, 

http://en.nim.ac.cn/ncmc/845, accessed September 14, 2015. 8 T.P. Heavner, E.A. Donley, F. Levi, G. Costanzo, T.E. Parker, J.H. Shirley, N. Ashby, S.E. Barlow, and S.R. 

Jefferts, 2014, First accuracy evaluation of NIST-F2, Metrologia 51(174). 9 F. Levi, C. Calosso, D. Calonico, L. Lorini, E. Bertacco, A. Godone, G. Costanzo, B. Mongino, S. Jefferts, T. 

Heavner, and E. Donley, 2009, “The Cryogenic Fountain ITCsF2,” pp. 769-773 in Frequency Control Symposium, 

2009, Joint with the 22nd European Frequency and Time Forum, IEEE International, 

doi:10.1109/FREQ.2009.5168289. 10 R. Jiménez-Martinez, S. Knappe, and J. Kitching, 2014, An optically-modulated zero-field atomic 

magnetometer with suppressed spin-exchange broadening, Review of Scientific Instruments 85:045124. 11 R. Jiménez-Martinez, D.J. Kennedy, M. Rosenbluh, E.A. Donley, S. Knappe, S.J. Seltzer, H.L. Ring, V.S. 

Bajaj, and J. Kitching, 2014, Optical hyperpolarization and NMR detection of 129Xe on a microfluidic chip, Nature 

Communications 5:3908. 12 P.J. Ganssle, H.D. Shin, S.J. Seltzer, V.S. Bajaj, M.P. Ledbetter, D. Budker, S. Knappe, J. Kitching, and A. 

Pines, 2014, Ultra-low-field NMR relaxation and diffusion measurements using an optical magnetometer, 

Angewandte Chemie Internationale Edition 53(37):9766-9770.
54

field of medical imaging.

13 This is an example of the TFD disseminating its time and frequency expertise 

to fields outside its core areas of responsibility. The TFD continues to demonstrate exceptional breadth of 

expertise in its dissemination.

Another aspect of time and frequency technology is related to the high-precision measurement of 

the phase noise of electromagnetic signals. The TFD excels at an international level in this field and 

disseminates its state-of-the-art expertise through numerous publications. For example, a recent article 

identified a weakness in the accepted means of measuring phase noise. The failure of these measurement 

techniques under certain conditions can lead to errors in phase noise magnitudes on the order of 20 dB.

14

The TFD engineers are also extending the range of frequencies over which precise phase noise 

measurements can be made, again disseminating information about this technique through publication.

15

Finally, research in the generation of ultrastable RF signals based on the use of optical transitions and 

optical combs is laying out a path to the future of ultralow-phase noise microwave signals.

16

Complementing its publications, the TFD presents a series of seminars and workshops addressing 

various aspects of precise timekeeping. The best known of these is the annual NIST time and frequency 

metrology seminar. Now in its fortieth year, this is the most comprehensive introductory seminar on the 

field of time and frequency in the world.

The final component of dissemination is the actual distribution of precise time information. For 

many years, the TFD has very successfully distributed time and frequency information in a number of 

ways. These include providing calibration services at the NIST Boulder campus, precise time distribution 

via various forms of radio transmissions, and, more recently, the distribution of time via the Internet. In

recent years there have been several noteworthy accomplishments in the area of dissemination. The TFD 

contributions of ultraprecise time and frequency information to UTC and its recent improvement through 

NIST-F2 have already been noted. The TFD led the formation of a near real-time international time scale 

among members of the Sistema Interamericano de Metrologia (SIM), a regional metrology organization 

whose members are nations of the Organization of American States.

17 The SIM Time Network is based 

on GPS common view intercomparisons between member state primary standards. Today the timing 

laboratories of 23 SIM member states participate in the SIM time network, and further expansion to more 

SIM members is planned. Timing information for the SIM Time Network is disseminated at the +/- 100 

ns level. A unique, recent accomplishment of this time scale is its real-time nature enabled by the 

Internet-based exchange of intercomparison information. In contrast, UTC is a backward-looking time 

scale with intercomparison information delayed two to four weeks. The real-time nature of the SIM time 

scale is an international first and is driving UTC to a more frequent dissemination of information. The 

TFD SIM time-scale efforts disseminate high-quality time throughout the western hemisphere and also

influence the global UTC scale.

At a lower level of precision, NIST, under TFD leadership, continues to broadcast precise timing 

information from high frequency and low frequency radio stations in Colorado and Hawaii to the 

continental United States and Pacific waters. With proper adjustment for propagation time and 

atmospheric conditions, this system can provide time information at the ±100 μsec level. Broadcasting in 

Colorado since 1965, the transmission system modified its transmission waveform in 2012, resulting in 

 13 O. Alem, A.M. Benison, D.S. Barth, J. Kitching, and S. Knappe, 2014, Magnetoencephalography of epilepsy 

with a microfabricated atomic magnetrode, Journal of Neuroscience 34(43):14324-14327. 14 C. Nelson, A. Hati, and D. Howe, 2014, A collapse of the cross-spectral function in phase noise metrology, 

Review of Scientific Instruments 85:024705. 15 A. Hati, C. Nelson, and D. Howe, 2014, PM noise measurement at W-band, IEEE Transactions on 

Ultrasonics, Ferroelectrics and Frequency Control 61(12):1961-1966. 16 S. Diddams, J. Li, X. Li, H. Lee, and K. Vahala, 2014, Electro-optical frequency division and stable 

microwave synthesis, Science Magazine 345(6194):309-313. 17 J.M. López-Romero, M.A. Lombardi, N. Diaz-Muñoz, and E. de Carlos-Lopez, 2014, SIM time scale, IEEE 

Transactions on Instrumentation and Measurement 62(12):3343-3350.
55

better coverage in areas that prior to the upgrade had poor reception.

18 The formal dissemination of time 

and frequency information has been markedly improved through this recent upgrade.

NIST TFD time dissemination efforts are also looking toward the future. The network-based 

dissemination of timing information is of growing importance to a variety of industries, including 

telecommunications and financial services. To meet growing needs the TFD is exploring the use of the

precise time protocol in optical networks.

19 These steps forward in the dissemination of timing 

information are distributed to the national and international technical communities through publications.

GPS common view techniques for time transfer, along with those enabled through communication 

satellites, have been in operation for many years. The TFD is now investigating more precise time transfer 

that could be enabled through use of a hydrogen maser on the International Space Station (ISS). The everimproving operational time dissemination services, along with research in this field, demonstrate a robust 

time dissemination program at the TFD. This program is at the leading edge of international activities in 

this field.

The emphasis on patent preparation does not appear to be stable from year to year. A careful 

assessment by the division of the value of patenting would be worthwhile. Once the value proposition is 

in hand, staff can be given more consistent direction.

The product dissemination efforts of the TFD are at the state of the art in this field and in many 

cases define it. The TFD has opportunities to advance the state of the art in several areas. These include 

improved global time transfer through use on an atomic standard on board the ISS and further 

improvement of network time transfer using the precision time protocol (PTP). The primary challenge to 

TFD progress is maintaining adequate funding for its diverse efforts in time and frequency and the 

ensuing dissemination of those products.

 18 Y.Liang, O. Eliezer, D. Rajan, and J. Lowe, 2014, WWVB time signal broadcast: An enhanced broadcast 

format and multi-mode receiver, IEEE Communications Magazine 52(5):210-217. 19 M. Weiss, L. Cosart, J. Hanssen, S. Hicks, C. Chase, C. Brown, C. Allen, P. Johnson, G. Wiltsie, and D.

Coleman, 2014, Ethernet time transfer through a U.S. commercial optical telecommunications network, pp. p. 214-

220 in Proceedings of Annual Precise Time and Time Interval Systems and Applications Meeting, Institute of 

Navigation, Manassas, Va.
56

10

Key Suggestions for Improvement

The quality of work done at the PML and its response to the stakeholders whose interests it 

addresses are excellent. Each division deserves high accolades, which are discussed at length in previous 

chapters. This chapter highlights key suggestions for improvement.

Applied Physics and Quantum Electromagnetics Divisions

The restructuring of the former Quantum Electronics and Photonics Division and 

Electromagnetics Division into the Applied Physics Division (APD) and the Quantum Electromagnetic 

Division seems to have been accomplished smoothly. However, the decision by the PML to have the 

panel jointly review the two divisions as one entity created some confusion and did not allow an in-depth 

analysis of either division. The APD as a consequence needs to be analyzed in more depth in coming 

reviews to provide a clearer view of its mission and how it integrates into the overall PML effort.

Engineering Physics Division

It will be important that PML avoid duplication of effort in the area of nontraditional materials 

conducted by better-funded teams investigating the science or technology of these speculative materials 

systems.

Quantum Electromagnetics Division

This optical quantum entanglement effort at the PML is among the many similar outstanding 

activities around the world. PML activity is not at the fundamental leading edge of science, but it is taking 

advantage of the superb photon sensors that the PML has developed. This activity is outstanding toward 

bringing QI science into practice, even though it may still take many years to accomplish that.

The work in nuclear magnetic resonance (NMR) imaging, while strong, needs to be expanded to 

include the rapidly growing area of functional NMR imaging (fMRI), so that claims made in the literature 

can be evaluated more carefully.

The Quantum Sensors Group has had a significant impact in millimeter wave polarimetry with its 

detector arrays, but the group serves so many external groups that it seems somewhat oversubscribed.

PML staff suggested that the Gaithersburg and Boulder nanofabrication facilities could support 

many more NIST projects or outside collaborators.

The new facility at the University of Maryland further disperses the division and could challenge 

current cohesiveness and collaborations.

PML staff reported that overhead charges on graduate students and on capital equipment are 

excessive.

The number of technical staff needs to be increased.
57

Office of Weights and Measures

The effort by the Metric Program to implement SI units in the United States is lagging. Better 

quantitative metrics for the effectiveness of the Legal Metrology group needs to be established. The 

number of accredited and recognized laboratories at the state level for dissemination of mass and volume 

standards for stakeholders is declining. 

PML predicts a large wave of retirements (50 percent of staff) in this office in the coming 5 years, 

and PML needs to examine the implication of the retirements and determine what replacements, if any, 

will be required.

Quantum Measurements Division

The partial relocation of the groups to the University of Maryland campus as the Joint Quantum 

Institute presents both opportunities and challenges that warrant careful monitoring so that the groups do 

not become isolated.

It will be important that the Synchrometrology Group have sufficient resources to play a role in 

the upcoming renovation of the national power grid into a smart grid. This effort will have a worldwide 

scope.

Quantum Physics Division

The Quantum Physics Division is likely to become increasingly involved in nanotechnology and 

biotechnology, broad areas in which careful planning will help to establish productive PML niches.

The scientific interests of the division show strong overlap with those of the Time and Frequency 

Division; this represents complementary activities in areas in which NIST is a world leader. The activities 

in biological physics have not been well integrated with those of other efforts within the Quantum Physics 

Division. PML needs to examine the relationship of biology to other division efforts. The division needs

to develop firm guidelines for a consistent and clear approach to the development of intellectual property.

Several staff mentioned that a high overhead rate on capital equipment makes acquisition of 

expensive equipment very difficult.

Radiation Physics Division

Building 245 in which the Radiation Physics Division is primarily housed is approaching a 

dangerous and unsafe condition; immediate attention is warranted. In the laboratories of Building 245, 

where most of the radionuclide standards are prepared for shipment, the rooms are old and lacking in 

proper heating and ventilation, with consequent inadequate control of humidity and temperature. Neutron 

source standardization is carried out in a number of shielded, below-grade laboratories in Building 245.

Water intrusion during heavy rains has become an issue, because the building is no longer watertight.

Dispersal of the source material is remotely possible, but the immediate concern is damage and loss of 

calibration traceability. These events are, at a minimum, distractions to overburdened scientists, and in 

some cases have threatened to flood sources under test.

The Dosimetry Group primarily works with its large stakeholder community, providing more 

opportunity and support to do research would enhance the quality of the staff and the work done.

Lack of funds is resulting in non-replacement of retiring critical employees and in requiring Ph.D. 

level staff to do routine tasks, stealing time from their technical work. Unfortunately, there are examples 

where dissemination of proper radioactivity standards has not been able to proceed as rapidly as required, 

owing to lack of funds.

The division needs to strengthen the training program that involves students and postdoctoral 

researchers in each of the critical standards activities and to foster a program to share equipment and 

facilities with users at other national laboratories and universities.
58

Sensor Science Division

One possible caution concerns the increasing emphasis on lower-cost, lower-SWAP sensors for 

future satellite systems. The division could prepare to calibrate much smaller radiometers for its 

customers.

As microfluidics becomes ever more important, it will be correspondingly important to continue 

developing noninvasive and in-line ways to determine microflows.

While the overarching strategy was well articulated, the division did not describe plans for some 

of the projects, particularly those that are funded externally; those working on internally funded initiatives 

seemed to have more concrete plans. The division needs to clarify plans for externally funded projects.

Retirements are being delayed because of difficulties in finding appropriate replacements.

Time and Frequency Division

The NIST-on-a-Chip effort will involve this division, which needs to expand development of its 

roadmap for this work.

The division’s scientific expertise evident during the review was primarily of an experimental 

nature. The division needs to consider whether the theoretical expertise resident within the division is 

sufficient to support future experimental efforts.

Challenges associated with shortage of meeting and collaboration space have been voiced by 

TFD staff. Staff also expressed concerns with respect to an onerous procurement process that incurs 

substantial delays. 

The emphasis on patent preparation does not appear to be stable from year to year. A careful 

assessment by the division of the value of patenting would be worthwhile. Once the value proposition is 

in hand, more consistent direction to staff can be provided.
59

Acronyms

AAPM American Association of Physicists in Medicine

AC alternating current 

AFM atomic force microscope

Al aluminum 

AMO atomic, molecular, and optical

APD Applied Physics Division

ASD Atomic Spectra Database 

BEOL back-end-of-line

BIPM Bureau International des Poids et Mesures

BMF Boulder Microfabrication Facility

cavity QED cavity quantum electrodynamics 

CIPM International Committee for Weights and Measures

CIRMS Council of Ionizing Radiation Measurements and Standards 

CMOS complementary metal-oxide-semiconductor

C-NOT controlled-NOT

CODATA Committee on Data for Science and Technology 

CT computed tomography 

DARPA Defense Advanced Research Projects Agency 

DC direct current 

DHS Department of Homeland Security 

DOC Department of Commerce 

DoD Department of Defense 

DOE Department of Energy 

DWSS DoD-focused DoD-wide strategic sourcing 

EBIT electron beam ion trap 

EDM electric dipole moment of the electron 

EPD Engineering Physics Division 

EPRI Electric Power Research Institute

FDA Food and Drug Administration 

FTS Fourier transform spectrometer

GaN gallium nitride

HFIR high flux isotope reactor
60

Hg mercury 

HgCdTe mercury cadmium telluride

HIA highly ionized atom

HPS Health Physics Society 

HSI hyperspectral imaging 

IEEE Institute of Electrical and Electronics Engineers

ILMP International Legal Metrology Program

IR infrared

ISO International Organization for Standardization

ISS International Space Station

ITL Information Technology Laboratory 

IUPAP International Union of Pure and Applied Physics

JHU Johns Hopkins University 

JILA joint institute between NIST and the University of Colorado, Boulder

JQI Joint Quantum Institute 

KRb ultracold potassium-rubidium 

LBIR low-background infrared

LIDAR light detection and ranging 

LMDP Legal Metrology Devices Program 

low-SWaP low size, weight, and power

mAb monoclonal antibody 

MBE molecular beam epitaxy

MDA Missile Defense Agency

MEMS microelectromechanical system

MRI magnetic resonance imaging

NCNR NIST Center for Neutron Research

NCSLI National Conference of Standards Laboratories International

NCWM National Conference on Weights and Measures

NGA National Geospatial-Intelligence Agency

NIH National Institutes of Health

NIST National Institute of Standards and Technology 

NMI national metrology institute 

NML national measurement laboratory

NMR nuclear magnetic resonance

NOAA National Oceanic and Atmospheric Administration 

NPOESS National Polar-Orbiting Operational Environmental Satellite System

NRC National Research Council

OCT optical coherence tomography 

OIML International Organization of Legal Metrology

OWM Office of Weights and Measures 
61

PACE preaerosol, clouds, and ocean ecosystem

PET positron emission tomograph(y)

PIF precision imaging facility 

PML Physical Measurement Laboratory 

PMU phasor measurement unit

PTB Physikalisch-Technische Bundesanstalt

QED Quantum Electromagnetics Division

QI quantum information

QMD Quantum Measurement Division 

QMS quality management system 

QPD Quantum Physics Division 

QuICS Quantum Information and Computer Science

R&D research and development

RF radio frequency

RPD Radiation Physics Division 

RSNA Radiological Society of North America

SANS small-angle neutron scattering

SEMI Semiconductor Equipment and Materials International 

SGIP Smart Grid Interoperability Panel

SI international system of units 

SIM Sistema Interamericano de Metrología 

SIRCUS spectral irradiance and radiance responsivity calibrations using uniform sources 

SNMMI Society of Nuclear Medicine and Molecular Imaging 

SQUID superconducting quantum interference device

SS solid state 

SSD Sensor Science Division 

SURF III Synchrotron Ultraviolet Radiation Facility

TDCR triple-to-double coincidence ratio 

TES transition edge sensor

TFD Time and Frequency Division 

UTC coordinated universal time 

UV ultraviolet 

VIIRS visible infrared imaging radiometer suite 

VUV vacuum ultraviolet 

Yb ytterbium