Physics Laboratory

This report is a summary of the technical activities of the National Institute of Standards and Technology (NIST) Physics Laboratory for the period January 2000 to December 2000. The Laboratory is one of seven major technical units of NIST.

The mission of the Physics Laboratory is to support U.S. industry by providing measurement services and research for electronic, optical, and radiation technology. More specifically, the Physics Laboratory aims to provide the best possible foundation for metrology of optical and ionizing radiation, time and frequency, and fundamental quantum processes.

The Physics Laboratory carries out this mission by conducting long-term research in measurement science; developing new physical standards, measurement methods, and critically compiled scientific and engineering reference data; promulgating these standards, methods, and data by providing calibration measurement services, standard reference materials, and electronic information services, and by publishing research results, holding conferences, and conducting workshops; participating in quality-assurance programs; and collaborating with industry, universities, and other agencies of government.

The Physics Laboratory maintains the U.S. national standards for the Système International (SI) base units of the second, the candela, and the kelvin (above 1200 K) as well as such SI derived units as the hertz, the becquerel, the optical watt, and the lumen.

Science and technology, once considered separate and sequential, are now becoming increasingly merged. Consistent with this trend, the Physics Laboratory is vertically integrated, spanning the full range of programs from tests of fundamental postulates of physics through generic technology to the more immediate needs of industry and commerce. Its constituencies are broadly distributed throughout industry, academia, and government, and include the other Laboratories of NIST. Its scope spans technologies based upon electronic, optical, and radiation-induced effects.

To tighten the relation between the performers of directed research and the industrial developers of advanced technologies, scientists in the Physics Laboratory work with industry and the other Laboratories of NIST to develop new measurement technologies that can be applied to areas such as communications, microelectronics, magnetics, photonics, lighting, industrial radiation processing, the environment, health care, transportation, defense, energy, and space. Cooperative research and development agreements, industrial research associates, committee participation, and consultations are all powerful mechanisms for transferring measurement capability to the private sector.

The Physics Laboratory has identified four strategic areas where it believes its experience and distinctive skills can contribute best to industrial and critical national needs, by providing measurement methods, instrumentation, standards, and data for:

• electronic and magnetic devices - to develop innovative measurement methods and techniques of use to the electronics industry for device characterization and electronic information and communication;
• optical technology - to provide the national basis for optical radiation measurement and to develop optical measurement systems for industrial and environmental needs;
• radiation applications and control - to support the innovative, effective, and safe use of radiation by providing standards and measurement quality assurance services, by developing and evaluating new radiation measurement methods, and by providing critical data;
• fundamental physical quantities - to improve definitions and realizations of base and derived SI units and to pursue opportunities for new determinations of fundamental physical constants.

The Laboratory's focus on atomic, molecular, optical, solid state, and ionizing radiation physics reflects the continuing importance of these disciplines in developing new measurement technology to address the needs of U.S. industry.

The Laboratory establishes spectroscopic methods and standards for microwave, infrared, visible, ultraviolet, x-ray, gamma-ray, and particle radiation; investigates the structure and dynamics of atoms and molecules, singly and in aggregate; and applies these results for practical purposes.

The Laboratory generates, evaluates, and compiles atomic, molecular, optical, and ionizing radiation data in response to national needs; develops and operates major radiation sources as user facilities; and maintains appropriate collaborations with other technical programs in NIST, the nation, and other institutions throughout the world. It conducts a major cooperative research program with the University of Colorado through JILA.

Whatever the criteria of success, the Laboratory is among the world’s leaders in basic and applied metrology. Its most productive scientists appreciate an environment where they can contribute to important practical programs as well as to strategic, fundamental research. The Laboratory’s great strengths include not only its multiple contributions to basic physics, chemistry, and materials science and its seminal role in fundamental measurement technology, but also the application of this measurement technology to specific industrial requirements.

The Physics Laboratory consists of six Divisions.

• Electron and Optical Physics Division. Provides the central national basis for the measurement of far ultraviolet and soft x-ray radiation; conducts theoretical and experimental research with electron, laser, ultraviolet, and soft x-ray radiation for measurement applications in fields such as atomic and molecular science, multi-photon processes, radiation chemistry, space and atmospheric science, microelectronics, electron spectroscopy, electron microscopy, surface magnetism, and solid state and materials science; determines the fundamental mechanisms by which electrons and photons transfer energy to gaseous and condensed matter; develops advanced electron- and photon-based techniques for the measurement of atomic and molecular properties of matter, for the determination of atomic and magnetic microstructure, and for the measurement and utilization of ultraviolet, soft x-ray, and electron radiation; develops and disseminates ultraviolet, soft x-ray, and electron standards, measurement services, and data for industry, universities, and government; and develops and operates well-characterized sources of electrons and photons including the NIST synchrotron ultraviolet radiation facility (SURF II), two scanning tunneling microscopes, and two scanning electron microscopes with unique magnetic imaging capabilities.

• Atomic Physics Division. Carries out theoretical and experimental research into the spectroscopic and radiative properties of atoms, molecules, and ions to provide measurement and data support for national needs in such areas as fusion plasma diagnostics, processing of materials by plasmas, spectrochemistry, illumination technology, and laser development; carries out high-accuracy determinations of optical, ultraviolet, x-ray, and gamma-ray transition energies; develops atomic radiation sources as radiometric and wavelength standards to meet national measurement needs; studies the physics of laser cooling and electromagnetic trapping of neutral atoms and ions; develops new measurement techniques and methods for analyzing spectroscopic data, for measuring plasma properties such as temperature and densities, and for determining fundamental physical constants; carries out theoretical and experimental research on quantum processes in atomic, molecular, and nanoscale systems, such as optical control of matter and semiconductor nanodevices and technologies; and collects, compiles, and critically evaluates spectroscopic data and creates databases to meet major national demands.

• Optical Technology Division. Provides national measurement standards and support services to advance the use and application of optical technologies spanning the ultraviolet through microwave spectral regions for diverse industries and governmental and scientific use; develops radiometric, photometric, spectroscopic, and spectrophotometric measurement methods, standards, and data; and promotes accuracy and uniformity in optical radiation based measurements through standards dissemination and measurement quality assurance services; to improve services and increase the accuracy, range, and utility of optical technologies, conducts basic, long-term theoretical and experimental research in optical and photochemical properties of materials, in radiometric and spectroscopic techniques and instrumentation, and in application of optical technologies; through these activities, meets the needs of industries such as the lighting, photographic, automotive, and xerographic industries; and provides measurement support to national needs in solar and environmental monitoring, health and safety, and defense.

• Ionizing Radiation Division. Provides primary national standards, dosimetry methods, measurement services, and basic data for application of ionizing radiation (x rays, gamma rays, electrons, neutrons, and radioactivity, etc.) to radiation protection of workers and the general public, radiation therapy and diagnosis, nuclear medicine, radiography, industrial radiation processing, nuclear power, national defense, space science, and environmental protection; conducts theoretical and experimental research on the fundamental physical interactions of ionizing radiation with matter; develops an understanding of basic mechanisms involved in radiation-induced chemical transformations and the parameters that influence the yields of short-lived intermediates, final chemical products, and biological effects; develops improved methods for radiation measurement, dosimetry, and radiography; develops improved primary radiation standards, and produces highly accurate standard reference data for ionizing radiation or radioactive materials; provides standard reference materials, calibrations, and measurement quality assurance services, to users such as hospitals, industry, states, and other federal agencies; and develops and operates well-characterized sources and beams of electrons, photons, and neutrons for primary radiation standards, calibrations, research on radiation interactions, and measurement methods development.

• Time and Frequency Division. (Boulder) Maintains, develops, and improves the national standards for time and frequency and the time scales based on these standards; carries out research in areas of importance to the further fundamental improvement of frequency standards and their applications, focusing on microwave and laser devices, atomic and molecular resonances, and the measurement of fundamental physical phenomena and constants; adapts time and frequency standard devices and concepts to special scientific and technological demands; develops time and frequency measurement methods in the radio-frequency, microwave, infrared, and visible radiation regions; coordinates the national time and frequency standards, time scales, and measurement methods nationally and internationally in conjunction with the United States Naval Observatory; operates time and frequency dissemination services, such as radio stations and broadcasts, for the purpose of traceability to the national standards of time and frequency; coordinates these services nationally and internationally; evaluates existing services in terms of present and future user needs and implements improvements as appropriate; assists present and potential users to apply NIST time and frequency services effectively to the solution of their particular problems; provides publications and consultations, and conducts seminars and demonstrations relating to NIST time and frequency dissemination facilities and services; and performs research and development on new dissemination techniques and, as appropriate, implements improved services based on these studies.

• Quantum Physics Division. (Boulder) Provides fundamental, highly accurate measurements and theoretical analyses using quantum physics, quantum optics, chemical physics, gravitational physics, and geophysical measurements; develops the laser as a refined measurement tool; measures and tests the fundamental postulates and natural constants of physics; applies atomic, molecular, and chemical physics to understand, predict, and control properties of excited and ionized gases and the pathways of chemical and material processes relevant to technology; improves the theory and instrumentation required to measure quantities such as Earth’s gravity, local gravity, and terrestrial distances; and maintains, through its association with JILA, the University of Colorado, and JILA’s Visiting Fellows Program, active contact with the education community.

In addition, two groups operate under the direct supervision of the Laboratory Office.

• Fundamental Constants Data Center. Provides a centralized international source of information on the fundamental physical constants, closely related precision measurements, and the international system of units; and periodically develops and widely distributes, in collaboration with outside international organizations, sets of recommended values of the fundamental constants.

• Office of Electronic Commerce in Scientific and Engineering Data. Coordinates and facilitates the dissemination of scientific and engineering data, generated by the Physics Laboratory, by means of available electronic networks; promotes the organization of the delivery of scientific, engineering, and technical data from its producers and publishers to U.S. industry by electronic means in the standard formats and computer readable forms required by U.S. industry for its timely and effective use; and coordinates the National Information Infrastructure initiatives of the Physics Laboratory.

This technical activities report is organized in seven sections, one for the Physics Laboratory Office, which includes the Fundamental Constants Data Center and the Office of Electronic Commerce in Scientific and Engineering Data, and one for each of the six Divisions. For each Division the report consists of brief statements of the Division's mission and organization, followed by a discussion of current directions, highlights of the year's accomplishments, and a discussion of future opportunities.

Following the technical activities sections are appendices that list: publications; invited talks; committee participation and leadership; workshops, conferences, and symposia organized; journal editorships; industrial interactions; other-agency research and consulting; calibration services and standard reference materials; and a list of acronyms used in this report. Each appendix is grouped by Division; if a Division is not listed in a particular appendix, it has nothing to report in this category.

To obtain more information about particular work, the reader should address the individual scientist or the Physics Laboratory office:

Physics Laboratory

National Institute of Standards and Technology,

100 Bureau Drive, Stop 8400

Gaithersburg, Maryland 20899-8400.

Our telephone number for responding to inquiries is 301-975-4200. Another useful resource is our website, physics.nist.gov. The website includes administrative and technical information, tables of evaluated reference data, research summaries, image galleries, and tutorial materials. It has won several awards for the quality of its content and presentation.