NIST Tech Beat - August 11, 2003

Editor’s Note: With the July 9, 2003 issue, we combined under one title two NIST newsletters, NIST Update and NIST TechBeat. We’ve made the change to help improve the timeliness of our topics. Our goal is to include newsworthy topics tied to publication of peer-reviewed papers, conference presentations, and other timely “news hooks” as often as possible. We also will be including photos and graphics whenever possible.
We hope you like the new look! Please let me know if you have any comments or suggestions.

New NIST Facility Soon Will Be ‘Reflecting’ on Safer Signs

Our roadways should get safer in the future, now that the National Institute of Standards and Technology (NIST) has developed a way to accurately and reliably measure how light reflects off stop signs and other road markings.

Road signs and markings are designed to be visible at night by retroreflectivity—that is, they reflect some of the light emitted by a vehicle’s headlights back toward the driver’s eyes. However, measurements of retroreflectivity have varied so much among different devices and laboratories that federal transportation officials have been unable to define minimum standards for this Congressionally mandated characteristic.

Recently, NIST established a facility—funded by the Transportation Research Board of the National Cooperative Research Program—that resolves numerous measurement problems and improves accuracy. Inside the facility, one finds a long black tunnel with a set of tracks on which sits an instrumented platform. Signs or materials are mounted on the platform, which can be moved 3 to 30 meters (10 to 100 feet) from a light source at one end of the tunnel. Using custom software, scientists precisely control all of the components and measure the characteristics of light reflected from the sign to a detector located close to the source.

NIST expects that the facility will begin providing calibration services early in 2004.

Finding Dirty Bombs and Other Radiation Threats

researcher using dectection device with truck

To receive a high-resolution version of this image, contact Gail Porter.

In an age of terrorism, law enforcement agents and other first responders need to be prepared for a wide range of threats, including so-called “dirty bombs” and other radiation hazards. To help ensure the performance of devices used to detect such threats, National Institute of Standards and Technology (NIST) researchers are working with the Institute of Electrical and Electronics Engineers (IEEE) and the American National Standards Institute (ANSI) to develop new standards for a variety of radiation detectors and monitors.

With partial funding from the Department of Homeland Security (DHS) and NIST’s Office of Law Enforcement Standards, NIST researchers are investigating a wide variety of detection devices, ranging from 3-meter-high portal towers that scan truck trailers while they move through checkpoints to small, pager-size monitors that serve as personal dosimeters. Many of these devices originally were designed for monitoring workers in factories and laboratories. The new standards under development will ensure that the devices work as intended under the new conditions now encountered in homeland security related tasks.

For example, some devices work differently in the rain or high humidity conditions, as well as in wide temperature ranges. So far, the NIST researchers also have found that the calibration of some detectors depends a lot on the exposure rate and energy of the radiation detected. The accuracy of 19 different hand-held detectors ranged within plus or minus 5 percent of the actual radiation value to plus or minus 40 percent depending on whether they were measuring high, medium or low energy radiation sources.

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

NIST Developing Virtual Reality Training Tool for Firefighters

To learn how to fight a fire, say those who work in this dangerous profession, you have to train in an actual blaze. But how do you safely prepare for that first blaze or fire situations that you’ve never seen before?

The National Institute of Standards and Technology (NIST) is developing a virtual reality simulation of fire situations that will enable fire professionals to demonstrate how life-threatening conditions can develop in structures and to test firefighting tactics on computers without risk to life and limb.

To build the most realistic physics-based computer fire simulations to date, NIST experts are reworking the agency’s fire modeling software—known as the Fire Dynamic Simulator (FDS)—and fire imaging program—known as Smokeview. Refinements to FDS will increase the system’s ability for simulating the smoke, hot air and other gas flow caused by fire, wind, ventilation and structural conditions. The upgrade also will improve data processing, yielding speedier calculations that will permit even the most complex fires (such as a multistory or multibuilding event) to be portrayed.

NIST will be working with firefighter instructors to develop a simulation of all of the possible outcomes for different fire scenarios used in training. These will be incorporated into a software package, enabling users to change a simulation with the click of a mouse. Immediately, firefighters will be able to learn the ramifications of actions such as opening a window, closing a door or focusing a hose spray in a certain direction. Enhancement of fire-related images, such as picturing “smoke” realistically on the computer screen (instead of denoting it symbolically with contours, dots or vectors) will add to “real” feel.

For a description of NIST’s current FDS and Smokeview software packages, see “Understanding Fire and Smoke Flow Through Modeling and Visualization” in the July-August 2003 issue of IEEE Computer Graphics and Applications. For more information on the virtual reality project, contact Glenn Forney, (301) 975-2313, gforney@nist.gov.

MEP Helps Small Kentucky Firm Play Big Role in Defense

While Semicon Associates may be a small company, it has some very big customers, including the U.S. military. Semicon manufactures communication systems components used in a wide variety of space, medical and military equipment, including the F-18 Hornet fighter aircraft and the Tomahawk cruise missile.

Although business has been good for the 80-employee company, Semicon managers wanted their firm to better serve current customers and expand its customer base. The Kentucky Manufacturing Assistance Center (KMAC), an affiliate of the National Institute of Standards and Technology (NIST) Manufacturing Extension Partnership (MEP), helped Semicon managers and employees assess the company’s short- and long-term market situation, reach a consensus about future directions, and develop and implement the steps needed to reach their goals. KMAC also helped the company implement the processes and standards needed to meet ISO (International Organization for Standardization) quality standards.

As a result, the company is more competitive and profitable; has reduced costs, lead times and defects; increased defense sales by about 20 percent; and created 10 new jobs.

“ As a mission-critical defense supplier, we at Semicon are very proud of the part we play in keeping our country’s defenses strong,” says Semicon President Jeffrey Waldal. “We are better able to serve our customers in the near term as a result of the Kentucky Manufacturing Assistance Center’s assistance … and … our firm has developed a roadmap that will lead to future success.”

For more information on KMAC, call (859) 252-7801 or go to www.kmac-mep.org. Details on the NIST MEP can be found at www.mep.nist.gov or manufacturers can reach the center serving their area by calling (800) MEP-4MFG (637-4634).

Single Photon Detector Conquers the Dark Side

Researchers from the National Institute of Standards and Technology (NIST) and Boston University have demonstrated a detector that counts single pulses of light, while simultaneously reducing false or “dark counts” to virtually zero.

Reported in the July 28, 2003, issue of Applied Physics Letters*, the advance provides a key technology needed for future development of secure quantum communications and cryptography.

Quantum communications and cryptography is a codemaker’s Holy Grail. The idea is to use a rapid series of light pulses (photons) in one of two different states to transmit information in an unbreakable code.

The photon detector project is part of a multi-disciplinary NIST effort to develop the sophisticated measurement methods needed to make quantum communication and cryptography possible. Funding was provided by the Defense Advanced Research Projects Agency (DARPA) and the NIST Advanced Technology Program (ATP).

Most current photon detectors operate best with visible light, cannot reliably detect single photons and suffer from high dark counts due to random electronic noise. The new device operates with the wavelength of near-infrared light used for fiber optic communications and produces negligible dark counts. Instead of using light-sensitive materials, the NIST device uses a tungsten film coupled to a fiber optic communication line. The film is chilled to 120 milliKelvin, at its transition temperature between normal conductivity and superconductivity. When the fiber optic line delivers a photon to the tungsten film, the temperature rises and the apparatus detects it as an increase in electrical resistance.

The device detects about 20,000 photons per second and works with an efficiency of about 20 percent. With planned improvements, the research team hopes to increase efficiencies to greater than 80 percent.

* Miller, A.J., Nam, S.W., Martinis, J.M. and Sergienko, A.V. Demonstration of a low-noise near-infrared photon counter with multi-photon discrimination, Applied Physics Letters (July 28, 2003), Vol. 83, No. 4, pp. 791-793.

NIST Helps Chip Industry Measure Features by Counting Atoms

The quest to develop the nanotechnology equivalent of ruler--length-measurement references based on the spacing of atoms in a perfectly ordered crystal--has inspired a burst of innovation at the National Institute of Standards and Technology (NIST). Progress to date has yielded a novel device that can resolve distances smaller than the radius of an atom and a reliable method for writing 10-nanometer-sized features on silicon.

NIST researchers are packaging the new technology and know-how into a scanning tunneling microscope (STM) system designed to write patterns with dimensions determined by counting the atoms that make up the patterns’ structural features. Ultimately aiming for an accuracy of better than 1 nanometer, the team intends to supply the semiconductor industry with benchmark references to calibrate measurement tools used in research and production.

To measure exceedingly small distances, members of the “atom-based artifacts project” developed a novel diode-laser based interferometer. The new, compact instrument incorporates elements of two types of existing interferometers—devices that determine the distance between two objects on the basis of light interference patterns—but achieves much higher levels of resolution. To date, the team has measured distances in increments smaller than 10 picometers, or less than one-hundredth of a nanometer.

Efforts to produce durable, silicon-based measurement references have paid off with a method for reliably writing patterns with 10-nanometer linewidths—equivalent to about 30 silicon atoms across. These STM-written patterns are long-lived, even outside of a vacuum, and recent work suggests that reactive ion etching can increase their three-dimensional relief.

Quick Links

NIST Receives Valuable Chemical Data from Dow: Dow Chemical Co. has donated an extensive collection of more than 50,000 infrared spectra—independently valued at more than $5 million—to NIST for incorporation into its Chemistry WebBook. The WebBook is an online resource (http://webbook.nist.gov/) that 600,000 users rely on annually for a wide range of research and development applications and educational purposes. To learn more, go to www.nist.gov/public_affairs/releases/dowchemical.htm.