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January/February 2003

  In This Issue:
bullet NIST 'Phantom Material' May Help Improve Metal Detectors
bullet NIST Helps U.S. Capitol with 'Overhead' Problem
bullet Improved Ocean Color Mapping When the NIST SIRCUS Is in Town
bullet New NIST Standards Say 'Hairs' to Better Drug Testing
bullet NIST/ISMT Laboratory Puts the 'Force' With Chipmakers
bullet 'Stone Cold' Video Showcases NIST's Hunt for New State of Matter
bullet Tech Trivia

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NIST ‘Phantom Material’ May Help Improve Metal Detectors

To ensure that security at the nation’s airports is as strong as it can be, metal detectors for detecting concealed weapons must be as sensitive as they can be. However, no one wants these devices to cause problems for innocent passengers using lifesaving personal medical electronic devices (PMEDs) such as cardiac pacemakers. The National Institute of Standards and Technology (NIST) soon may be able to help solve the dilemma.

Providing the solution to this problem may be a new, NIST-developed semisolid “phantom material” that can simulate the electromagnetic characteristics of different human body tissues over a range of frequencies. Created by researchers in NIST’s Radio-Frequency Technology Division, the moldable material (a carbon black-silicone composite) could be embedded with PMEDs, and then sent through a metal detector to determine the effect of the generated magnetic fields on the function of pacemakers, hearing aids, infusion pumps and the like.

Currently, some metal detector manufacturers insert test objects in a liquid that mimics the conductivity of different body tissues, but the objects can shift within the liquid and produce varying readings. Additionally, many test liquids evaporate or are unstable over time.

The new NIST semisolid material can be made to match the conductivity of any body tissue and, because of its rigidity, keeps the PMEDs in a test sample fixed. This material can be made to emulate the electrical properties of a human for the frequencies over which walk-through and handheld metal detectors operate.

This research was funded by the Office of Science and Technology at the National Institute of Justice through NIST’s Office of Law Enforcement Standards.

Media Contact:
Fred McGehan (Boulder), (303) 497-7000



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Historical Restoration Camera Icon- Click for link to photo

NIST Helps U.S. Capitol with ‘Overhead’ Problem

1859 Cross-Section Drawing of the U.S. Capitol Dome and Rotunda
1859 Cross-Section Drawing of the U.S. Capitol Dome and Rotunda

Repairing a leaky roof usually doesn’t require the expertise and skills of researchers at the National Institute of Standards and Technology (NIST)—unless the building in need of help is one of the nation’s most treasured edifices.

When the 150-year-old dome of the U.S. Capitol in Washington, D.C., began leaking during heavy rainstorms a few years ago, the Office of the Architect of the Capitol consulted with engineers involved in welding research at NIST. The daunting task handed them: return the cast-iron supporting structure of the dome’s outer shell to its original condition without replacing the cracked castings or losing any of the iron work’s historical integrity.

That request sparked a search for the right weld that would integrate with 1850s technology. An initial attempt in 1998 failed when the test welds cracked. NIST engineers went back to the drawing board (and the lab) to develop and test other options. The best-working technique turned out to be oxyacetylene braze welding (a flame repair process where the filler metal melts at a temperature below that of the casting) combined with a copper-zinc alloy called low-fuming bronze. The bronze forms joints that are very similar in strength to the original castings.

NIST’s experts have submitted their recommendation to the Architect’s office.

Media Contact:
Fred McGehan (Boulder),  (303) 497-7000Up


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EnvironmentCamera Icon- Click for link to photo

Improved Ocean Color Mapping When the NIST SIRCUS Is in Town

As a result of recent measurement corrections made possible by the National Institute of Standards and Technology (NIST), the Earth’s oceans may look a bit bluer than they did before in satellite images—meaning there may be less carbon in the oceans than previously thought.

A unique NIST tabletop-sized instrument, called the “traveling SIRCUS” (a miniature version of the agency’s Spectral Irradiance and Radiance Calibrations with Uniform Sources facility), was transported to Hawaii last year to calibrate the Marine Optical Buoy systems (known as MOBY) that measure the color and magnitude of light reflected from and within the ocean. Data from these systems are used to calibrate satellite-borne color mapping instruments.

Ocean color is important in climate research because variations in the visible light spectrum reflect the concentration of microscopic marine plants, which utilize carbon dioxide from the ocean/atmosphere system for photosynthesis. These phytoplankton absorb blue light and reflect predominantly green light, whereas water reflects predominantly blue.

The satellite observations are used to produce global assays of biomass and carbon production in the world’s oceans.

The laser-based traveling SIRCUS helped correct errors in the buoy’s measurements.

The corrections are having an impact on scientists’ calculations of the biomass and carbon concentrations present in the oceans, which will provide a more accurate understanding of Earth’s carbon balance and its effect on climate.

Media Contact:
Laura Ost,  (301) 975-4034Up


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Law Enforcement

New NIST Standards Say ‘Hairs’ to Better Drug Testing

Traditional methods of screening job applicants, athletes and others for illicit drug use increasingly are being supplanted or complemented by hair analysis, which offers several testing advantages. The accuracy of such hair tests now can be quality assured through the use of two new Standard Reference Materials (SRMs) from the National Institute of Standards and Technology (NIST).

The new NIST standards, which consist of human hair segments that have been soaked in solutions containing target drugs, help validate the accuracy of test methods for detecting those drugs. The first, SRM 2379, is designed for tests of stimulants (“uppers”) such as cocaine and PCP. Its companion SRM, number 2380, checks tests for depressants (“downers”), such as codeine and THC (the active ingredient in marijuana).

As new hair tissue forms in the roots, drugs and other chemicals from the bloodstream may be absorbed into and retained by the growing follicles. Hair’s advantages in drug testing—when compared to using fluids such as urine—are that it can be collected more easily, is more difficult to switch or contaminate, and retains traces of drugs for at least 90 days (not just two or three). However, hair analysis generally is not applicable to the detection of drug use initiated within the past 10 days. Therefore, it may be favored as a complement to, rather than a substitute for, traditional methods.

NIST began researching the analysis of drugs in hair in 1990 and has conducted seven interlaboratory comparison exercises to see how well different methods work, and in some cases, how well different laboratories conduct such tests.

Media Contact:
Laura Ost,  (301) 975-4034



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NIST/ISMT Laboratory Puts the ‘Force' With Chipmakers

S tar Wars fans know that things go better when the force is with you. While that force helps solve galaxy-sized problems for the Jedi Knights, scientists and engineers at the National Institute of Standards and Technology (NIST) have teamed up with the semiconductor industry to put the force—atomic force microscopy (AFM), that is—to work at the other end of the size spectrum.

Microchip manufacturers frequently need to measure dimensions of only 100 nanometers (four-millionths of an inch or about one-thousandth the width of a human hair) within the devices they create. This is especially true for “critical dimensions” (known as CD in the industry), the smallest size that can be etched into a computer chip uniformly. To ensure that chipmakers can accurately and consistently assess CD, NIST has set up a special semiconductor chip processing laboratory with AFM at International SEMATECH (ISMT) in Austin, Texas. The outputs of this lab are reference standards for the industry—standards contained in microchips that have dimensional features measured with accuracy approaching the level of the distances between atoms in a silicon crystal.

NIST’s CD reference standards consist of micro-machined silicon crystal materials that act as “rulers” for calibrating instruments that make minuscule measurements during the chip manufacturing process. A one-of-a-kind atomic force microscope, operated by NIST personnel assigned to ISMT, can reveal important information about tiny surface features on a chip with unprecedented clarity.

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


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PhysicsCamera Icon- Click for link to photo

'Stone Cold' Video Showcases NIST's Hunt for New State of Matter

It was a scientific milestone that many said would never be realized. Some called it the “Holy Grail of physics.” But on June 5, 1995, physicists Eric Cornell of the National Institute of Standards and Technology (NIST) and Carl Wieman of the University of Colorado at Boulder observed the Bose-Einstein condensate (BEC) for the first time. It had been 71 years since Albert Einstein predicted that a new state of matter would be created if individual atoms melded into a “superatom” at temperatures approaching absolute zero.

For their breakthrough, Cornell and Wieman shared the 2001 Nobel Prize in Physics with Wolfgang Ketterle of MIT.

Recently, Cornell gave a public lecture at NIST’s Gaithersburg, Md., headquarters on his research entitled “Stone Cold Science.” The lecture was videotaped, and the VHS-format program is now available at no charge from NIST.

In the 74-minute video, Cornell chronicles the search for the BEC, describing in detail just what the “weird world of physics at a billionth of a degree from absolute zero” is like. The program will be of great interest to high school, college and graduate-level physics students and teachers, as well as anyone fascinated by the process leading to scientific discovery.

To request a free copy of the educational video, write to NIST Public Inquiries, 100 Bureau Dr., Stop 3460, Gaithersburg, Md. 20899-3460, fax a request to (301) 926-1630, or send an e-mail message to

Media Contact:
Laura Ost,  (301) 975-4034Up


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Tech Trivia

In the 1956 science-fiction film “Earth vs. the Flying Saucers,” a lightweight helmet captured from the alien invaders is said to have been examined by the “Bureau of Standards” (NIST was the National Bureau of Standards, or NBS, from 1901 until 1988). The Bureau scientists, says a general, determined that the helmet was made from “solidified electricity.”

The People’s Almanac (1975) states in the section on the 1945 disappearance of five Navy planes in the Bermuda Triangle that “In 1965-1966, NBS studied the coastline along the edge of the Triangle, using special microphones and instruments to pick up ultrasonic noise. They did hear some strange whispering sounds, but technicians could not identify them.” While NBS researchers did measure the speed of sound in the ocean in the 1950s, no “whispering sounds” were ever noted.

A NIST physicist and his former colleague were prominently mentioned by name in Tom Clancy’s Net Force: Night Moves (2000). David Wineland of NIST’s Time and Frequency Division and Christopher Monroe, now at the University of Michigan, are described on page 126 of the book as having “worked out the single quantum gate by trapping beryllium ions.”

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Editor: Michael E. Newman

Date created:02-20-03