NIST Tech Beat - March 6, 2006

Scientists at the National Institute of Standards and Technology (NIST) working with Russian colleagues have significantly improved the design of optical atomic clocks that hold thousands of atoms in a lattice made of intersecting laser beams. The design, in which ytterbium atoms oscillate or “tick” at optical frequencies, has the potential to be more stable and accurate than today’s best time standards, which are based on microwaves at much lower frequencies. More accurate time standards could improve communications, enhance navigation systems, and enable new tests of physical theories, among other applications.

Described in two papers in the March 3 issue of Physical Review Letters,* the heart of the clock consists of about 1,000 pancake-shaped wells made of laser light and arranged in a single line, each containing about 10 atoms of the heavy metal ytterbium. The lattice design results in fewer systematic errors than optical atomic clocks using moving balls of cold atoms, and also offers advantages in parallel processing over other approaches using single charged atoms (ions). The optical lattice, created by an intense near-visible laser beam, is loaded by first slowing down the atoms with violet laser light and then using green laser light to further cool the atoms so that they can be captured. Scientists detect the atoms’ “ticks” (518 trillion per second) by bathing them in yellow light at slightly different frequencies until they find the exact “resonant” frequency (or color) that the atoms absorb best.

Previous lattice-based clocks have used atoms with odd-numbered atomic masses, which have a nuclear magnetic field that causes some additional complications. The new clock uses atoms with even-numbered atomic masses that have no net nuclear magnetic field but have been difficult to use in atomic clocks until now. The researchers found they could apply a small external magnetic field combined with yellow laser light to induce an otherwise “forbidden” oscillation between two energy levels in the atoms. The team reported an extremely precise resonance frequency with a strong signal that demonstrates the clock’s potential for very high stability. The new approach is also applicable to other atoms with even-numbered atomic masses, such as strontium and calcium, which are under study at NIST and other research laboratories around the world.

The Russian guest researchers are affiliated with the Institute of Laser Physics of the Siberian Branch of the Russian Academy of Sciences and Novosibirsk State University, both in Novosibirsk, Russia. The work was supported in part by the National Research Council and Russian Fund for Basic Research.

* Z.W. Barber, C.W. Hoyt, C.W. Oates, L. Hollberg, A.V. Taichenachev and V. I. Yudin. 2006. Direct excitation of the forbidden clock transition in neutral 174Yb atoms confined to an optical lattice. Physical Review Letters. March 3.

** A.V. Taichenachev, V.I. Yudin, C.W. Oates, C.W. Hoyt, Z.W. Barber and L. Hollberg. Magnetic field-induced spectroscopy of forbidden optical transitions with application to lattice-based optical atomic clocks. Physical Review Letters. March 3.

The Consumer Product Safety Commission (CPSC) issued an improved flammability standard* for mattresses and mattress foundation sets last month that should significantly reduce deaths and injuries in bedroom fires started by such common open-flame sources as lighters, candles and matches. Mattresses and sets that comply with the new standard requirements will burn more slowly when put in contact with an open flame than many current products. The standard was developed with assistance from the National Institute of Standards and Technology (NIST).

Slower mattress burning rates should reduce the possibility of flashover, the point at which the entire contents of a room are ignited simultaneously, making conditions in the room untenable and safe exit impossible. By allowing time to escape the fire, the CPSC estimates, the new mattress standard should annually save an estimated 270 lives and prevent 1,330 injuries.

In announcing the new regulations, CPSC Chairman Hal Stratton said, “NIST’s contribution to CPSC’s development of this standard was invaluable.” The test methods, created by NIST, with the support of the mattress industry’s Sleep Products Safety Council, quantify the product’s increased fire resistance. Mattress and set prototypes, using the NIST test, pass the new CPSC performance requirements if, in a 30-minute period in which their product is subjected to open flames, the peak heat release rate does not exceed 200 kilowatts (kW) and the total heat release does not exceed 15 mega joules (MJ) in the first 10 minutes of the test. This heat release rate is substantially below the heat release rate of approximately 1,000 kW, which leads to flashover in a typical room.

The CPSC does not specify how manufacturers are to design their mattresses to meet the standard. The new federal standard for mattresses and sets goes into effect on July 1, 2007.

Interoperability Standards Events Set for March 13-17

Too many software standards can be just as bad as no standards at all, especially if those standards don’t address the issue of “interoperability,” the ability to communicate across different formats. That’s the concern of National Institute of Standards and Technology (NIST) experts who worry that incompatible standards can have the same effect as proprietary software in impeding data exchange between researchers or industrial partners. To help address the issue, NIST has organized an “interoperability week” March 13-17 on its Gaithersburg, Md., campus, as a venue for a variety of independent workshops, each addressing some aspect of interoperability.

Workshop participants will discuss interoperability or harmonization prospects for (1) XML standards used in electronic commerce to exchange supply chain data information, quotes and contract requirements; (2) Open Information and Communication Technology (ICT) standards used in the global economy for manufacturing engineering and health care data records; (3) sensor standards used in rescue efforts or to detect biological, radiological, chemical or nuclear threats; (4) advanced semantic languages (also called “upper ontologies”) used in fields such as biomedical research and computer guided manufacturing processes; and (5) knowledge representation and archival methods designed to allow future researchers to access digital data perhaps hundreds of years from now.

A “collaboration expedition workshop” for federal officials, IT researchers and developers will review emerging information technologies under the Government’s “Federal Enterprise Architecture” and e-government initiatives as well as offer suggestions on how focus groups on specific standards can be formed. A subsequent XML Community of Practice meeting during the week will offer participants an example of how organizations and individuals with common interests share information and leverage activities to achieve interoperability objectives. Interoperability speakers at the March 14 plenary session will include private-sector representatives and congressional policy officials.

The agenda of “Interoperability Week at NIST March 13-17 is available at http://www.mel.nist.gov/div826/msid/sima/interopweek/meetings.htm.

Media Contact:
John Blair, john.blair@nist.gov, (301) 975-4261

Much of science these days depends on “black (or beige) boxes,” scientific instruments that invisibly analyze data and then, voilá, identify the chemistry and/or structure of a sample. While scientists and engineers may be glad that the data crunching is invisible, the quality of the data used is critically important to something that they do care deeply about—getting an accurate answer.

Through two years of meticulous evaluation studies, the National Institute of Standards and Technology (NIST) has helped ensure that “black boxes” that identify crystal structures will have the best possible data. The NIST Structural Database is a compilation of chemical data and three-dimensional crystal structures for approximately 20,000 materials, primarily metals, alloys and intermetallics. (Intermetallic materials are compounds of two or more metals with mechanical properties often resembling a cross between metals and ceramics.)

While the database has been available previously, this latest upgrade features a re-evaluation of all 20,000 crystal structures to ensure that the highest quality data are included. The upgrade efforts include improved standardization of the data provided for each structure and additional data fields for each entry. The structure data provided can be imported into Virtual Reality Modeling Language (VRML) players that allow researchers to view the structures in three dimensions and to rotate them in space.

The database is typically licensed by software companies and instrument manufacturers. For example, the database may be incorporated into software used to identify chemical compositions and/or crystalline structures using electron diffraction. Diffraction instruments work by aiming a beam of radiation (such as X-rays, electrons, neutrons, etc.) at a sample and then analyzing the resulting scattering patterns produced.

For further information on licensing, contact the NIST Ceramics Division, (301) 975-6119.

President Bush’s Health Information Technology Plan calls for ensuring that most Americans have electronic health records within the next 10 years and for developing an internet-based Nationwide Health Information Network to connect patients, practitioners and payers. These initiatives are designed to reduce redundancies and save administrative time, and could greatly improve patient safety and quality of care.

In testimony before the House Subcommittee on Environment, Technology, and Standards on Feb. 23, 2006, William Jeffrey, director of the National Institute of Standards and Technology (NIST), discussed the agency’s role in healthcare and in helping to make this plan a reality.

As part of an interagency agreement signed in September 2005 by NIST and the Department of Health and Human Services, NIST is providing technical expertise to the Office of the National Coordinator (ONC) for Health Information Technology. NIST’s activities in health information technology include:

Secretary of Commerce Carlos Gutierrez has appointed three prominent industry and education leaders to serve on the 10-member panel of judges for the Malcolm Baldrige National Quality Award to replace retiring panel members. The Baldrige Award is the nation’s highest Presidential award for quality and organizational performance excellence.

The new members are: Paula Friedman, corporate vice president, strategy and systems improvement, SSM Health Care, St. Louis, Mo.; William (Bo) McBee, vice president, total customer experience & quality, Hewlett-Packard Company, Houston, Texas; and Diane Kramer Siri, superintendent of schools, Santa Cruz County, Capitola, Calif. Another new judge is yet to be appointed. David C. Branch, chairman and chief executive officer, Branch-Smith Resources, Ltd., Fort Worth, Texas, was appointed as the new chair of the panel.

The panel of judges is part of the award’s mostly private-sector board of about 500 examiners who review applications for the Baldrige Award. The judges review examiner comments and scores, select applicants for site visits and recommend Baldrige Award recipients to the Secretary of Commerce.

Other judges are: Lloyd Barker, Alcoa, Inc., New York, N.Y.; James R. Evans, University of Cincinnati, Cincinnati, Ohio; Steven D. Hagedorn, Mayo Clinic Rochester, Rochester, Minn.; Steven C. Lampa, Marriott International Corp., Washington, D.C.; and Maureen M. Travalini, Kaiser Permanente CSC, Fort Worth, Texas.