An Assessment of the National Institute of Standards and Technology Chemical Science and Technology Laboratory: Fiscal Year 2007 (2007)

The Process Measurements Division’s (PMD’s) mission of disseminating national measurement standards for thermodynamic parameters and conducting relevant measurement science research fits well with national priorities and NIST focus areas. PMD provides essential calibration services in fundamental parameters that support many sectors of the U.S. economy as well as facilitate international commerce. It conducts research that is directly aligned with NIST and national priorities. Examples include research supporting the Department of Homeland Security (microsensor chemical detectors), the climate change research community (spectroscopy, gas properties), the biopharmaceutical industry (gold nanoparticle reference material), developers of the hydrogen economy (hydrogen gas data and flow rate), and the semiconductor industry (atomic layer deposition, humidity, and trace gas measurements). In those parameters for which PMD maintains U.S. national standards and provides measurement services, it is generally preeminent among NMIs. This division is an important national resource. The overall mood of PMD staff appears to be positive, with researchers who are dedicated to maintaining and enhancing the international stature of the division.

The NIST mission and current national priorities place increasing demands on technologies and services that are the responsibility of PMD. The technologies necessary for nanomanufacturing, the production of biofuels, enabling the hydrogen economy, development of clinical diagnostics and therapies, measuring climate change, and other national priorities can be developed no faster than the underlying process measurements on which they depend. Advances in temperature, pressure, humidity, material properties, and other fundamental measurement areas are essential to the exploitation of new technologies as well as to accomplishing the goals outlined in the American Competitiveness Initiative. For example, research is necessary in PMD parameters to keep up with the rapidly changing demands of nanotechnology. An array of technologies must be advanced to address homeland security issues, and these technologies will put pressure on process measurements and the underlying measurement science for which PMD is responsible. For example, evaluating climate change calls for significant improvements in the measurement of atmospheric parameters and better knowledge of the properties of atmospheric gases. To make practical use of hydrogen, accurate information about the gas (viscosity, speed of sound, flow rate, and the like) is needed.

PMD’s goals include the following:

• Research to improve national measurement standards for temperature, fluid flow, liquid volume and density, pressure, vacuum, humidity, and airspeed.

• Developing the science base that supports new and improved measurements and standards technologies.

• Dissemination of measurement resources and technology through calibration services, SRMs, standard reference data, proficiency testing at the customer’s site, and other means.

PMD has been improving measurement services and making them more automated. The division staff have reduced uncertainties in many parameters. For example, the measurement of gas viscosity is now accurate to ±0.08 percent in the range from 200 K to 400 K. Intermediate-range gas flow measurement uncertainty has been reduced from ±0.13 percent to ±0.009 percent. These improvements have benefited the semiconductor and gas flow instrumentation industries, among others. The new trace gas humidity system will measure to 14 ppb at ±1.8 percent uncertainty, a competitive advantage for U.S. producers of industrial gas and manufacturers of semiconductors. Hydrogen gas data are now available, with uncertainties of ±0.08 percent for viscosity and ±9 ppm for speed of sound. A new, less expensive calibration service is planned for completion in 2008 for mid-range vacuum calibration.

The potential impact of success in PMD research areas is also significant. U.S. dominance in nuclear technology, hydrogen technology, the application of biofuels, biopharmaceutical manufacturing, and nanotechnology will require major innovations and advances in the measurement technologies for which the division is responsible. A few examples of research programs that could have a very large impact are listed below.

• Because its performance is based on fundamental physical phenomena, the Johnson noise thermometer (JNT) could provide a means of placing temperature measuring systems within the cooling systems of next-generation nuclear reactors and in satellites, maintaining accuracy without needing to be removed for calibration. The same device has research applications that include improving the temperature scale, to which it is already being applied at NIST. The JNT technology will soon also be applied by NIST-Boulder to improve AC voltage measurements.

• In response to the needs articulated by the NCI, gold nanoparticle reference materials are being developed as part of CSTL’s work on technologies for future measurement standards. Accurate cell phenotying requires quantitative analysis of images containing gold nanoparticles. In this connection, it is necessary to know that all the nanoparticles are of the same size and to know the specific size of the bare particle after each surface modification, which PMD researchers have demonstrated by a creative application of differential mobility analysis. Successful dissemination of gold nanoparticles as NIST

reference materials may facilitate new treatments for cancer and other diseases.

• Advances in gas concentration standards, spectroscopic relative intensity standards, and in measurement of pressure, temperature, and humidity—all of which are active programs in PMD—will improve the monitoring of climate change and will support semiconductor manufacturing as well as a wide range of other desirable objectives.

• More accurate property data for hydrogen (speed of sound and viscosity) will be used in a number of applications essential for moving the nation to a hydrogen economy.

• Chemical sensors using PMD-developed microhotplate technology may make possible reliable alarms for poisonous gases under real-world industrial and military conditions.

• PMD is developing models and metrology techniques for plasma-based processing of semiconductor devices such as atomic-layer deposition of high-k dielectrics for next-generation transistors.

• The hybrid humidity project, nearing completion, takes advantage of the expertise and scientific knowledge about humidity that is uniquely available in PMD, including operational knowledge gained by operating the U.S. national standard for humidity.

• The atomic standard of pressure program is attributable to PMD’s expertise in resonant acoustic and millimeter-wave techniques for determining gas properties. At present the system may demonstrate within months its potential to revolutionize pressure calibration by replacing piston gauges as primary pressure standards.

• PMD is a leader in the area of micromachined chemical sensors. Especially noteworthy is the division’s demonstration that arrays of microsensors can recognize low concentrations of toxic industrial compounds in high background levels of reactive interferants. Applications for this technology include chemical warfare agent detection on the battlefield.

• A new instrument, dubbed the “whispering gallery” resistance thermometer and based on the properties of sapphire, is being developed as a means of measuring temperature without relying on mechanically fragile platinum resistors.

• The National Aeronautics and Space Administration has requested a calibration database of the chemical species involved in determining the dynamics of CO₂ in the atmosphere. PMD-developed cavity ring down spectroscopic measurements will provide these spectroscopic parameters at the required ±0.3 percent uncertainty level for the 2008 launch of the Orbiting Carbon Observatory, designed to monitor global climate change.

• A comprehensive, three-tiered proficiency testing program in temperature has been implemented to support customers from the highest level (standard platinum resistance thermometers) to the factory level (thermocouples). To maintain accreditation, proficiency testing support is essential for commercial laboratories that perform calibration. This new service is advertised in the Bulletin of the National Voluntary Laboratory Accreditation Program.

In most calibration and measurement areas, the PMD has superb measurement capability, and it maintains this capability through continuous process improvements and research. One example is the ultrasonic interferometer manometer, which is used to produce the best primary standard of pressure. Since moving to the Advanced Metrology Laboratory it achieves an uncertainty of 3 ppm in a room whose temperature is controlled within ±0.1°C. These measurement capabilities are foundational to U.S. competitiveness, especially in new and emerging technologies. The large number of publications, committee leaderships, and visiting U.S. and foreign scientists and postdoctoral fellows testifies to PMD’s technical reputation and leadership position in measurement science.

Many of the division’s measurement capabilities are among the finest of their type, as reflected by both informal and formal key comparison analyses conducted by NMIs for the primary pressure standard (CCM.P-K4 and -K5), liquid volume (CCM.FF-K4), natural gas at high pressure (CCM.FF-K5.a), and compressed air and N₂ (CCM.FF-K5.b). PMD continues to develop and initiate new calibration services (e.g., for humidity and trace humidity in 2006).

In FY06 division researchers produced 55 manuscripts for publication, had 30 manuscripts accepted for publication, made 94 presentations, produced 6 patents, and participated on 73 committees, generally as committee leaders.

In a number of areas the division experienced declines in full-time equivalent (FTE) positions, such that Ph.D.s charged with essential calibration missions do not have sufficient time for research because they do not have enough technical support staff. The risk of continuing along this path is that Ph.D. researchers will either leave NIST or lose the expertise necessary to advance metrology. There is a need to maintain proficiency and competency in developing standards; a calibration laboratory cannot be sustained with technicians alone. A continuation in the decline of FTEs will necessitate cuts in calibration services and have negative repercussions for U.S. industry and commerce. CSTL should consider applying a differential cost recovery system for calibration services and a new fee system for these services within the federal guidelines governing NIST’s mandate.

PMD plays a key role in accomplishing the NIST mission, which is unique and differs from that of academia, commercial, and other government research organizations in that it focuses on measurement science, the development of metrological tools, and calibration standards. Its resources include experts in specific technical areas along with some of the best measurement and calibration systems. Together, these resources give PMD unique capabilities and strengths that are reflected in the wide range of research programs and measurement programs in which it is involved.

Better PMD calibration services enhance U.S. competitiveness, promote science and technology, and further the NIST mission. The Department of Defense, Department of Homeland Security, Department or Energy, and U.S. industry depend upon NIST to define measurement uncertainties and to serve as the legal link to the International System of Units.