The Bureau's International Scope

As the national measurement laboratory of the United States, NBS is a prominent member of the international research and standards communities. The Bureau is actively involved in several international standards-setting organizations, including the International Bureau of Weights and Measures, the International Organization for Legal Metrology, and the International Standards Organization.

Outside of this formal standards arena, the Bureau also has direct contact with individual standards and research organizations in developed and developing countries around the globe. This liaison facilitates the intercomparison of a variety of measurement standards and allows NBS to share in the latest world developments in science and technology.

Another facet of the Bureau's international role is its assistance to other Federal agencies in policymaking on international science and technology issues. Last year, for instance, NBS helped the Department of State to

accuracy and precision are just a few of the prospects.

Over the years, NBS has helped usher in a revolution in measurement science and in our ability to test fundamental physical theories through application of laser technologies. Using new laserstabilization techniques they had developed, physicists at the Joint Institute for Laboratory Astrophysics (JILA)-operated by NBS and the University of Colorado-last year reconfirmed and improved upon one of the seminal experiments fundamental to scientific knowledge about time, distance, and motion.

Known as the Michelson-Morley test of "ether drift," this famous 1887 experiment has been basic to the development of the special theory of relativity by Einstein, Lorentz, and

prepare for the 1979 United Nations Conference on Science and Technology for Development. This conference-the first of its kind since 1963-covers several aspects of the use of science and technology to benefit developing countries.

The Bureau works frequently on a oneto-one basis with scientists and engineers from other countries. For example, NBS last year hosted 42 guest workers from 17 countries who participated in a broad range of research projects. This international exchange allows the Bureau to draw upon the expertise of researchers around the world and offers foreign scientists and engineers an opportunity to become directly involved in studies at NBS. (For more information on this and other exchange programs, see page 66.) This science and technology sharing is enhanced further by representatives of foreign governments, standards-writing organizations, and industries who visit the Bureau's laboratories. During FY 1978, NBS received 695 such visitors from 55 nations.

others. In part, this theory holds that space is isotropic-that is, the same in all directions. In 1964, Massachusetts Institute of Technology scientists Townes and Javan demonstrated that the accuracy of that experiment could be increased by using laser measurement technology.

With the assistance of a guest worker from the Laboratoire de l'Horloge Atomique in France, JILA physicists have developed and put new laser stabilization techniques to work in dramatically improving upon the earlier tests of isotropy. The recently achieved results represent a 4,000-fold improvement over the 1964 experimental accuracy. With sufficiently sensitive measurements of this type, it may be possible in the future to actually measure the effects of the curvature of

space due to the gravitation of massive bodies, such as the earth or the sun.

Much of the basic research at the Bureau not only adds to our fundamental scientific knowledge base, but also finds specific-and many times diverse-applications in science and technology.

A number of recent achievements in the Center for Thermodynamics and Molecular Science illustrate this type of research. A prime example is the application of a technique (ion-cyclotron resonance) which can be used to measure the thermodynamic properties associated with the transfer of electrons in mixtures of gaseous organic compounds. This method has relevance in comprehending not only the chemical processing of hydrocarbons but also the behavior of certain dynamic biological processes like photosynthesis.

Similarly, recent accomplishments in explaining the process whereby the chemical bonds joining carbon atoms to each other are split apart have their roots in the most basic NBS molecular science and measurement skills. This work in the Center for Thermodynamics and Molecular Science holds clear promise for important applications in controlling and optimizing the way fossil fuels perform during combustion.

Another achievement by scientists in that center exemplifies the multiple directions in which basic research can lead. By studying the millimeter-wave spectrum of glycine in its vapor phase, NBS scientists resolved years of conjecture among chemists and biologists about the geometrical form glycine vapor takes. More detailed studies now made possible by the NBS research are expected to yield information which will be useful in modeling biochemical reactions of amino acids, the building blocks of proteins. At the same time, the results are already being put to use in a search by radioastronomers for glycine in interstellar molecular clouds. Discovery of biological molecules such as glycine could revolutionize our current ideas about the origin and natural evolution of life.

In addition to those projects cited elsewhere in this report, some of the other significant NBS achievements of the past year which increase the Nation's measurement capabilities are noted below.

Scientists in the Center for Thermodynamics and Molecular Science:

⚫ developed a new way to "fingerprint" liquid fossil fuels, including gasolines, fuel and machine oils, and industrial hydrocarbon solvents. Utilizing photoionization mass spectroscopy, the technique can be used by police laboratories to compare such fluids and by scientists and engineers who need to know more about the characteristics of alternative fuels like shale oils and coal liquefaction products.

introduced a new factor to be considered in modeling the ionosphere by developing a novel technique (threshold photoelectron spectroscopy) to analyze chemicals believed to be similar to those found in that portion of the atmosphere, but which are not ordinarily observable because of their low concentration.

made measurements of the thermodynamic properties of rapidly heated graphite in a study supported by the U.S. Air Force. These measurements will provide the Air Force with information about graphite employed as a heat shield material for rockets. They will also improve understanding of the performance of fuel and structural solids in nuclear reactors.

⚫ established a service for calibrating low and medium vacuum measurement instruments. This service provides an accuracy 10 to 100 times greater than previous services and is being used extensively by industry.

NBS physicist James E. Faller checks

out the new "super spring," a device for

mechanically isolating sensitive

equipment from extremely low-level

vibrations. The super spring was

developed at the Joint Institute for Lab

oratory Astrophysics, a research

organization operated by NBS and the University of Colorado.

better than 20 microseconds, providing users with accurate information regardless of their location.

demonstrated a technique by which the accuracy of today's cesium standardswhich serve as the international basis for the definition of the second-may be improved by a factor of 10. This improvement would have a great impact in rapidly expanding use of such standards for position location, collision avoidance, and communications applications.

⚫ developed a device, called a "super spring," that will help isolate equipment from the disturbing influence of vibrations as low in level as the earth's natural microseismic background activity.

⚫ established a new way to calculate the rotational and vibrational energy levels of spherical-top molecules, greatly simplifying the analysis of high resolution

Measurement: The Bureau's Forte (continued)

spectra. The new method will help researchers studying laser isotope separation, time and frequency standards, and laser-induced chemistry.

⚫ participated in an international comparison of ac-to-dc transfer standards. These standards play a critical role in verifying the performance and accuracy of ac test and measurement instrumentation. U.S. standards were found to be in excellent agreement with those of the U.S.S.R., Japan, and the United Kingdom.

achieved a stability of two parts in one billion in a room temperature LC resonator, a device for controlling frequency. By far the most accurate in the world, this device opens up a new level of sensitivity for inductance and capacitance measurements and has potential for application to temperature, pressure, magnetic susceptibility, and displacement measurements.

Scientists and engineers in the Center for Mechanical Engineering and Process Technology:

⚫ designed and developed a new lowvelocity airflow facility which can produce a uniform airflow with minimal turbulence at velocities as low as 3 meters per minute. Laser-optic methods are used as the primary velocity standard. In a series of tests, a number of anemometers were evaluated for the U.S. Bureau of Mines. These results will help establish accurate safety standards for mine ventilation. The same facility also allowed NBS to serve as a third party resource for the General Services Administration and a private contractor, demonstrating that precise specifications for ventilation in a new multimillion dollar office building were feasible.

⚫ developed a new "Facility for Analyzing Surface Texture," which will aid in characterizing the topography of highperformance optical surfaces and assist in research designed to extend the lifetimes of gyroscope bearings by improving measurement of surface finish. The facility also has been used to study the wear in communications satellites' electrical contacts and to help judge specimens used as Standard Reference Materials for

calibrating instruments in the machine tool and other industries.

measured the thermal expansion properties of crude and refined petroleum drawn from approximately 400 sources around the world. These measurements are crucial to the computation of petroleum volumes and thus to the value of shipments. The work was accomplished with the support of the American Petroleum Institute.

• developed mathematical models that have greatly improved our understanding of the fundamental operation of industrial flowmeters, which are used to measure liquids and gases ranging from water, sewage, and oil to natural gas and air. Errors and uncertainties in flow measurement are becoming increasingly important, especially in the metering of liquid fuels where small percentage errors can make a difference of substantial sums of money.

Scientists and engineers in the Center for Electronics and Electrical Engineering:

completed measurements on the largest antenna ever evaluated by near-field scanning techniques which were developed at NBS. There are no conventional (farfield) means for measuring an antenna of this size to the required accuracy. The new NBS measurements will help calibrate earth terminals of satellite communication systems.

⚫ developed a new method, known as the "six-port" technique, that is likely to have a major impact on the design of equipment that automatically records microwave and high frequency measurements. More accurate, simpler, and less costly than traditional methods, the Bureau's innovation will permit microwave specialists to tailor their measuring equipment to their particular requirements rather than procure a general-purpose instrument with excess measurement capabilities. The transfer of this technology was facilitated by a Research Associate Program sponsored by a major aerospace and data communications system manufacturer.

used radio stars as a standard signal source to make high accuracy measure

ments of satellite-earth terminal sensitivity at extremely high frequencies (above 6 gigahertz). These measurements will become increasingly important as commercial communication satellites move into these higher frequency ranges in the early 1980's.

⚫ compared electrical energy measurement standards of the United States, West Germany, and Canada, revealing previously undetected systematic errors and pointing to a need for periodic comparison. High accuracy is essential in these measurements, which are used to calculate the amount of electricity one utility system supplies to another, for instance.

Researchers in the Center for Materials
Science:

⚫ developed a technique for measuring the viscosity of liquids at extreme pressures. This is yielding data with important implications for the manufacture and use of the "superlubricants" that will be needed for new machine designs.

made a comparative study of flame temperature measurements by conventional optical methods and novel Raman spectroscopic techniques. The results have demonstrated improved levels of accuracy and have defined the conditions needed for accurate and reproducible temperature measurements used in combustion research and flame inhibition studies.

⚫ successfully obtained pressure measurements on a Bureau of Engraving and Printing press equipped by NBS with a new pressure sensing device made from piezoelectric polymers, an unusual class of materials with which NBS is experimenting in a number of new applications. This agency has not previously been able to make the sensitive measurements permitted by the NBS device and needed for quality control in the printing of currency.

⚫ developed a new instrument for use in nondestructive evaluation of materials using neutron beams. This "multidetector high-resolution diffractometer for neutron diffraction-profile analysis" is the first of its kind in the United States.

Researchers in the Center for Analytical Chemistry:

⚫ studied unusual characteristics of a meteorite which suggest that it is "primitive," that is, relatively unchanged since its formation. Primitive meteorites are of special interest to scientists since they provide one of the best clues to the early makeup of our solar system. NBS studied the meteorite in cooperation with scientists from the Smithsonian

Institution. They were able to examine the material and assess its characteristics by using an extraordinarily sensitive ion microprobe.

demonstrated a new technique for measuring the fluctuations in concentrations and the average concentration of individual chemicals in a turbulent gas flow. The improved accuracy in measurement afforded by this research, performed in conjunction with the NBS Center for Fire Research, is important to our understanding of flame and combustion processes and efforts to achieve more fuel-efficient, less polluting combustion.

⚫ developed two Standard Reference Materials (SRM's) for wheat and rice flours. These SRM's will help assure the

accuracy of measurements of important constituents in flour present only at very low concentration. Developed with partial support of the Food and Drug Administration, these measurement references will assist environmentalists, medical researchers, nutritionists, and other food scientists who are interested in the nutrients and contaminants contained in cereal foods-the source of one-fourth of the total caloric intake of the U.S. population.

The Center for Radiation Research:

completed a measurement of the radius of the carbon nucleus to an unprecedented accuracy, within 10 attometers (i.e., +10x10-18 meters). This new value will become the benchmark against which other nuclei are measured and will be fundamental to measurement in nuclear physics.

measured the continuous light output of a single electron orbiting in a magnetic field. This technique permits radiometry to be placed on an absolute physical basis (that is, in terms of orbit radius and magnetic field strength). Synchrotron light in the far ultraviolet wavelength region is being used at NBS for a variety of research projects in atomic, solid, and biological systems.

• developed a reliable, high current source of polarized electrons for studying the spin-dependent interactions of electrons with materials. The electrons are produced using the photoelectric effect in a semiconductor with circularly polarized light. Expected to be of great importance in areas of basic research such as surface science, this steady, reproducible electron source has already found application in significant research projects at NBS and other U.S. laboratories.

A unique low-velocity airflow facility has been designed and developed at NBS. Researchers Patrick Purtell (left) and Philip Klebanoff examine a vane anemometer that has been tested in the facility for the U.S. Bureau of Mines. The test results will help establish accurate safety standards for mine ventilation.