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November/December 2001

In This Issue:
bullet Ultracold Plasmas Are a Chilling Puzzle
bullet A Trip to the ‘Library’ May Help Catch Computer Villians
bullet New NIST Test Says ‘Y’ Be Uncertain about DNA Identification
bullet New Imaging Tool Has X-Ray Eyes
bullet NIST Named National Historic Chemical Landmark
bullet Video Says ‘SURF’s Up’ Again for NIST Summer Student Program
bullet Tech Trivia

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Ultracold Plasmas Are a Chilling Puzzle

Plasmas, which include the bright glowy stuff in a fluorescent lamp, are clouds in which ions and free electrons move around independently as charged particles. Plasma is thought to be the most common form of matter in the universe, but it’s usually pretty hot. The plasma in a solar corona can have a temperature in the millions of degrees. Researchers at the National Institute of Standards and Technology’s Physics Laboratory, however, have created “ultracold” plasmas—with the electrons about a degree above absolute zero—by cooling neutral atoms to within a hundred-thousandth of a degree of absolute zero and then zapping them with just enough laser energy to separate the electrons and ions to achieve the plasma state.

One of the key measures of any plasma is the recombination rate—how fast the ions and electrons recombine to form neutral atoms. Theory says there are three main recombination processes, and their efficiency varies in a known way with temperature and density. However, NIST physicist Steven Rolston says that in practice, an expanding ultracold plasma recombines much faster than expected at very low densities—so much faster that no existing theory describes it.

Rolston and his group are continuing to refine their experiments to explain the behavior of ultracold plasmas, which, although they only exist in earthly labs, are thought to model the interior of white dwarf stars or gas giant planets like Jupiter. The research also may uncover a path to synthesizing “anti-hydrogen” atoms, the antimatter equivalent of hydrogen. Precise comparisons of the properties of such antimatter twins may probe the fundamental nature of the forces that bind matter and the universe together.

Media Contact:
Michael Baum,  (301) 975-2763



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Law Enforcement

A Trip to the ‘Library’ May Help Catch Computer Villains

Criminals who use computers in their work frequently manipulate files in an attempt to hide or obscure their activity. For example, someone involved in the sale of child pornography might try to hide a photographic image file in a computer—such as a “jpeg” or “bitmap” file—by renaming it to make it look like another type of file.

While computer forensics experts know these tricks, they frequently face the daunting task of searching up to 100,000 files on a single desktop computer for evidence. Now, computer scientists at the National Institute of Standards and Technology are providing a means of speeding up these previously time-consuming evidence searches.

Working with software manufacturers and others who provided copies of their programs, NIST has developed the National Software Reference Library. The NSRL allows law enforcement agencies to eliminate between 25 percent to 95 percent of the total files in a computer, concentrating only on those that really might contain evidence. It works by providing a verified reference data set of file “fingerprints” based on file contents rather than other identifiers such as file name or header information.

Several federal agencies support the effort, including the National Institute of Justice, the Federal Bureau of Investigation, the U.S. Customs Service, the Technical Support Working Group and the Defense Computer Forensics Laboratory.

Media Contact:
Philip Bulman,  (301) 975-5661Up


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New NIST Test Says ‘Y’ Be Uncertain about DNA Identification

When researchers sought to learn whether President Thomas Jefferson had a child with a slave, they used a “Y chromosome test” that showed the boy was fathered by someone from the President’s family. Such tests indicate both the presence of male DNA in a blood or tissue sample—only males have Y chromosomes—and the family it came from, because the markers (particular chemical sequences) identified in the test are inherited.

Such tests were not used widely in the past because of a number of uncertainties. But usage is expected to increase now that the National Institute of Standards and Technology’s Chemical Science and Technology Laboratory has developed a more detailed and reliable method and, in turn, is creating a Standard Reference Material that labs will use to calibrate their instruments and validate test performance. The new test identifies 20 markers on the Y chromosome instead of the six used in older tests; the standard is expected to be ready for sale next year.

The new NIST methodology and SRM are expected to help simplify paternity testing as well as eliminate current problems distinguishing between male and female DNA in forensic and human ID tests.

The markers used in the test are short, brief chemical sequences repeated in pairs—often many times—in a DNA molecule. They vary enough in a population to distinguish individuals and produce good analytical results. None of the markers are believed to occur on X chromosomes, carried by both males and females.

Media Contact:
Michael E. Newman,  (301) 975-3025


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New Imaging Tool Has X-Ray Eyes

Researchers at the National Institute of Standards and Technology have developed a new way of seeing—with X-ray “eyes” no less. Using its novel instrument, the NIST team can clearly glimpse minute voids, tiny cracks and other sometimes indiscernible microstructural details over a three-dimensional expanse in a wide range of materials, including metals, ceramics and biological specimens.

In its current form, the technology—called ultra-small-angle X-ray scattering or USAXS imaging—functions much like a film camera, albeit a highly specialized one. And where a camera needs a flash to create images, USAXS has the ultimate flash—the Advanced Photon Source at the Argonne National Laboratory. Measuring 1,104 meters (nearly 0.7 mile) around, the APS is a new-generation synchrotron. It produces an abundance of extremely uniform high-energy X-rays that make the new imaging technique work.

USAXS itself is an already established research technique, yielding plots of data points that correspond to angles and intensities of X-rays scattered by a specimen. With the new system, graphed curves become high-resolution pictures. And when taken from different perspectives, pictures can be assembled into three-dimensional images.

Images are actually maps of the small fraction of X-rays that—instead of being absorbed or transmitted through the sample—are scattered by electrons in the material.

Media Contact:
Mark Bello, (301) 975-3776Up


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NIST Named National Historic Chemical Landmark

The American Chemical Society, the world’s largest scientific society, has declared nearly 40 places, discoveries and achievements as national historic chemical landmarks. Among the facilities honored over the years are the Chandler Chemistry Laboratory at Lehigh University in Bethlehem, Pa. (the first in the United States built specifically to train industrial chemists); the University of California, Berkeley’s Gilman Hall (site of the identification of plutonium); and New York’s Rockefeller University (home to five Nobel laureates in chemistry for breakthrough work on proteins and nucleic acids).

Now, you can add the National Institute of Standards and Technology to the illustrious ACS list.

The landmark designation awarded NIST by the ACS is an outstanding tribute that caps off an exciting centennial year for the agency. NIST was cited as having “made broad-based and comprehensive contributions to chemical science and technology and to the economic strength and competitiveness of the United States.” ACS added that NIST “continues to demonstrate that the intelligent application of research in physical sciences to a wide range of societal changes contributes to a higher quality of life for everyone.”

For more information about the National Historic Chemical Landmarks program, including the NIST declaration, go to

Media Contact:
Michael Newman,  (301) 975-3025Up


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Video Says ‘SURF’s Up’ Again for NIST Summer Student Program

Since 1993, the National Institute of Standards and Technology—with support from the National Science Foundation—has opened up its laboratories to undergraduate students each summer, giving these young scientists and engineers a golden opportunity to work alongside some of the world’s leading experts in science and technology. Known as the Summer Undergraduate Research Fellowship—or SURF—the program offers students majoring in science, mathematics and engineering 12 weeks of unique hands-on learning and direct participation in research efforts within the physics, materials science, chemistry, applied mathematics, computer science or engineering environments at NIST’s Gaithersburg, Md., headquarters.

The 2002 SURF program is expected to run between May 28 and August 16 of next year. Applications—which are submitted by colleges and universities, not individual students—must be in by Feb. 15, 2002.

Persons and organizations wanting to know more about the SURF program should get a VHS video or compact disc copy of a new video available from NIST titled “Wave of the Future: In Their Own Words.” In the 8-1/2 minute show, former SURF students reflect on their experiences in the laboratory, within the NIST campus, and around the Greater Washington, D.C., area.

For a copy of the SURF video or to get more information on the fellowships, contact the SURF Program, NIST, 100 Bureau Dr., Stop 8400, Gaithersburg, Md. 20899-8400; The video and program details also are available online at

Media Contact:
Michael Newman,  (301) 975-3025Up


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Tech Trivia

The NIST Museum in Gaithersburg, Md., contains a sample of platinum-iridium that was tested for its properties by the United States Office of Weights and Measures in 1889. The alloy—which is harder, more rigid and less likely to corrode than brass—was being used at the time to manufacture the international meter bar and kilogram standards, copies of which arrived in the United States the following year from France to serve as the nation’s length and mass standards.

Another weights and measures artifact in the NIST Museum is a precision equal-arm, two-pan Rueprecht balance, constructed in Austria about 1901. It was purchased by NIST’s predecessor, the National Bureau of Standards, in 1945 and used until 1960 to calibrate copies of the kilogram standard housed at NBS. The whole instrument was encased in glass to lessen the effects of the environment on the performance of the balance.

The recipe calls for a tablespoon full of sugar but all you’ve got is a teaspoon. Three teaspoons will give you the required amount. This conversion, along with others between commonly used kitchen units of measurement, may be found on the NIST Office of Weights and Measures web site at

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Editor: Michael E. Newman

Date created: 12/6/01