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September 14, 2004

  In This Issue:
bullet Scientists Tame 'Hip Hop' Atoms
bullet A Simpler Design for X-Ray Detectors
bullet Emergency 'Shoelacing' for Fractured Phone Systems
bullet Protecting Buildings from Airborne Threats
bullet Testbed to Link Metrology Tools/Software

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Scientists Tame 'Hip Hop' Atoms

NIST logo spelled out with cobalt atoms
Joseph Stroscio; Robert Celotta / NIST
Click on image for high-resolution version.

A 40-nanometer-wide NIST logo made with cobalt atoms on a copper surface. The ripples in the background are made by electrons, which create a fluid-like layer at the copper surface. Each atom on the surface acts like a pebble dropped in a pond.

In an effort to put more science into the largely trial and error building of nanostructures, physicists at the National Institute of Standards and Technology (NIST) have demonstrated new methods for placing what are typically unruly individual atoms at precise locations on a crystal surface.

Reported in the Sept. 9, 2004, online version of the journal Science, the advance enables scientists to observe and control, for the first time, the movement of a single atom back and forth between neighboring locations on a crystal and should make it easier to efficiently build nanoscale devices "from the bottom up," atom by atom.

Colorized version of an image created by the NIST custom-built scanning tunneling microscope as it drags a cobalt atom across a closely packed lattice of copper atoms.
Joseph Stroscio; Robert Celotta / NIST
Click on image for high-resolution version.

Colorized version of an image created by the NIST custom-built scanning tunneling microscope as it drags a cobalt atom across a closely packed lattice of copper atoms. Large round features show the cobalt atom bonding to the copper at its preferred, lowest energy bonding site. Bright triangle-shaped areas show the atoms bonding at a higher energy site. The atom "screeches in protest" when the STM tip forces it to sit at this site. Dark areas show positions that the atom "hops" over, refusing to bond at all.

Click here to hear "sounds" of hip hop atoms
(You will need Real Player on your computer in order to view. Download Real Player free of charge at the Real.Com FreePlayer website.)

The NIST team was surprised to find that the atoms emitted a characteristic electronic "noise" as they moved between two different types of bonding sites on the crystal surface. By converting this electronic signal into an audio signal, the researchers were able to "hear" the switching take place. The sound resembles a hip hop musician’s rhythmic "scratching" and can be used by researchers to know in real time that atoms have moved into desired positions.

Several research groups already are using specialized microscopes to build simple structures by moving atoms one at a time. The NIST advance makes it easier to reliably position atoms in very specific locations. "What we did to the atom is something like lubricating a ball bearing so that less force is required to move it," says Joseph Stroscio, co-author of the Science paper.

Such basic nanoscale construction tools will be essential for computer-controlled assembly of more complex atomic-scale structures and devices. These devices will operate using quantum physics principles that only occur at the atomic scale, or may be the ultimate miniaturization of a conventional device, such as an “atomic switch” where the motion of a single atom can turn electrical signals on and off.

**J.A. Stroscio and R.J. Celotta. 2004. Controlling the Dynamics of a Single Atom in Lateral Atom Manipulation. Science Express, Sept. 9.

For more information, see

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



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A Simpler Design for X-Ray Detectors

A simplified design for ultra-sensitive X-ray detectors offering more precise materials analysis has been demonstrated at the National Institute of Standards and Technology (NIST). The advance is a step toward making such devices cheaper and easier to produce. Users may eventually include the semiconductor industry, which needs better X-ray detectors to identify and distinguish between nanoscale contaminant particles on silicon wafers.

The new design, described in the Sept. 13 issue of Applied Physics Letters,* is among the latest advances in a decade of NIST research on superconducting "transition edge" sensors (TES). These cryogenic sensors absorb individual X-rays and then measure the energy of the X-ray by measuring the resulting rise in temperature. The temperature is measured with a bilayer of normal metal and superconducting metal that changes from zero resistance (superconducting) to a slight resistance level in response to the heat from the radiation. By measuring the X-ray energy, NIST researchers can identify the X-ray "fingerprints" of particular elements.

NIST researchers have built systems offering 30 times better X-ray energy resolution than detectors now used in the semiconductor industry and are pursuing further improvements such as novel detector geometries and materials. In contrast to the usual bilayer TES design, the sensor described in the APL paper combines the normal and superconducting metals into one homogenous layer. Manganese impurities are added to a 400-nanometer-thick aluminum film to lower its superconducting transition temperature to 100 milliKelvin. Fabrication requires about half as many steps as the bilayer design. In addition, the new design exhibits less "noise" in the X-ray signals than is typical for TES sensors, as well as a low sensitivity to magnetic fields that could help in building stable instruments.

Scientists at the University of Notre Dame and Santa Clara University also participated in the research. The work was supported in part by NASA.

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

*S.W. Deiker, W. Doriese, G.C. Hilton, K.D. Irwin, W.H. Rippard, J.N. Ullom, L.R. Vale, S.T. Ruggiero, A. Williams and B.A. Young. 2004. Superconducting transition edge sensor using dilute AlMn alloys. Applied Physics Letters, Sept. 13.



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Emergency 'Shoelacing' for Fractured Phone Systems

When a major disasterman-made or naturaltakes down the phone system, who ya gonna call? No one, 'cause the phone’s dead, right? … Not if you're using a novel emergency communications system under development by the Maryland start-up TeleContinuity Inc. With initial support from the National Institute of Standards and Technology’s Advanced Technology Program (ATP), TeleContinuity is creating a “survivable” emergency telephone system back-up network that keeps individuals, companies and government agencies in touch during disasters by seamlessly merging conventional phone lines and the Internet.

Telecontinuity’s system represents a shift from traditional disaster recovery and business continuity solutions that historically have focused on location-based backup facilities and centralized telecom infrastructures.

The terrorist attacks of Sept. 11, 2001, severely disrupted phone service at the attack sites, particularly in New York, where the collapse of the World Trade Center damaged a major local phone central office. Days and even weeks later, many companies and individuals were still without phone service. During this time, however, Internet links, utilizing different lines and network architectures, operated continuously. TeleContinuity’s founders realized that short-term, emergency phone service could be activated quickly, on any scale, by cross-linking surviving phone system links and Internet links as necessary, a technique they called “shoelacing.”

The company says its initial version of the software for such an emergency system is designed to reroute a user’s phone service within minutes of a major telephone outage by delivering the call to a remote phone, cellphone or even a computer or PDA. By the end of the ATP project in the spring of 2005, the company plans to develop an enhanced version of the software that allows administrators and users to monitor and control networks in an emergency with advanced Web-based controls. Ultimately, commercialization of the technology will require a network of hundreds of nodes that can quickly lace together phone and data network lines regardless of where in the system an outage occurs.

Researchers from the University of Maryland and the University of Pittsburgh assisted in developing the system.

Information on the TeleContinutity ATP project is at, and the company’s Web site is at\

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



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Protecting Buildings from Airborne Threats

A building’s ventilation and air distribution system can play a critical role in protecting occupants from airborne chemical, biological and radiological (CBR) agents, according to National Institute of Standards and Technology (NIST) researcher Andy Persily.

In an article in the September issue of ASHRAE Journal,* Persily, group leader in NIST’s indoor air quality and ventilation program, urges the development of strategies that minimize the impact of CBR events in buildings. He says that a building’s ventilation system can be used to actively protect occupants by diluting CBR agents with outside air, driving contaminants to filters or other air-cleaning equipment, or by selectively depressurizing vulnerable parts of the building. Lower pressures in mail rooms, loading docks and lobbies, for instance, could inhibit CBR movement to the rest of the building.

NIST is currently developing building pressurization strategies that take into account weather conditions, envelope air-tightness and building architecture, particularly building height. Such pressurization systems might be used with ventilation, interior partitions and air-cleaning systems to create emergency “shelters in place” as a refuge for occupants or a safe escape path.

Before considering ventilation changes to address airborne threats, Persily stressed that building owners and managers should understand fully the capabilities of their existing building systems. Otherwise, some changes could make the situation worse. He also warned against making changes to reduce CBR vulnerability that degrade indoor air quality or comfort during normal conditions.

Media Contact:
John Blair,, (301) 975-4261

*A. Persily, Building pressurization as a security tool, ASHRAE Journal, September 2004.


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Testbed to Link Metrology Tools/Software

Continuous inspection of product dimensions is critical in modern manufacturing. A finished product, and all its parts, must fit dimensional specifications. To meet this demand for precision, manufacturers and suppliers regularly use coordinate measuring machines along with inspection planning, execution and analysis programs. Too often, however, these quality control components do not communicate well, particularly when components are mixed and matched from different vendors. The result can be substantial costs to manufacturers who must translate data from one system to another, retrain workers or even buy new machines for their production lines.

The National Institute of Standards and Technology (NIST) has established a testbed at its Gaithersburg, Md., headquarters to help manufacturers improve the interoperability of their dimensional measurement systems. The testbed is using NIST-developed test methods and tools to verify that specific equipment and software conform to new industry standards designed to allow subsystems to "talk" to one another even if they come from different manufacturers.

The NIST testbed was debuted at the International Manufacturing Technology Show in Chicago, Sept. 8-15. The demonstration features the use of two draft standard "languages" being used to link together 10 major measuring components.

Successful implementation of such standards throughout manufacturing should save users time and money, avoid code rewriting and measurement errors, and ultimately encourage a more competitive business environment with lower costs.

Media Contact:
John Blair,, (301) 975-4261


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Quick Links

Two NIST Scientists Earn Presidential Award

Two researchers at the National Institute of Standards and Technology (NIST) were among those honored as recipients of the 2003 Presidential Early Career Awards for Scientists and Engineers on Sept. 9. NIST physicist Scott A. Diddams was honored for his achievements in applying new methods of optical frequency "combs" to measure frequency with unprecedented accuracy, an area that promises to produce the next-generation of atomic clocks. NIST mechanical engineer Jon R. Pratt was recognized for his contributions in the fields of fundamental measurement science, manufacturing research, and precision engineering, including realization and dissemination of the unit of force at the micro- and nano-scale.

The award is the nation’s highest honor for professionals at the outset of their independent research careers. Fifty-seven researchers were recognized in a ceremony presided over by John H. Marburger III, science advisor to the President and director of the White House Office of Science and Technology Policy.

The Presidential Early Career Awards for Scientists and Engineers, established in 1996, honor the most promising beginning researchers in the nation within their fields. Eight federal departments and agencies annually nominate scientists and engineers at the start of their careers whose work shows the greatest promise to benefit the nominating agency’s mission. Participating agencies award these beginning scientists and engineers up to five years of funding to further their research in support of critical government missions.

For more information, see

NIST to Support Cancer Nanotechnology Lab

As part of a new $144.3 million, five-year initiative to develop and apply nanotechnology to cancer research and treatment, the National Institute of Standards and Technology (NIST) and the National Cancer Institute (NCI) have signed a new memorandum of understanding and an interagency agreement. The agreement calls for NIST to provide technology support to a key component of the initiative (known as NCI Alliance for Nanotechnology in Cancer), the Nanotechnology Characterization Laboratory (NCL) at NCI's facility in Frederick, Md. The NCL will perform and standardize the preclinical characterization of nanomaterials developed by researchers from academia, government and industry. The NCL will serve as a national resource and knowledge base for cancer researchers, and facilitate the accelerated regulatory review and translation of nanomaterials and devices into the clinical realm. For information about the NCI Alliance for Nanotechnology in Cancer, go to

September Meetings Planned on Voting Systems

The Technical Guidelines Development Committee, established by the Help America Vote Act, will hold a series of three meetings on the voluntary voting standards development process. Each day’s hearing will be on a specific topic: Sept. 20, Computer Security and Transparency; Sept. 21, Core Standards Requirements and Testing; Sept. 22, Human Factors and Privacy. One hour will be reserved each day for the public and the election community to provide testimony on technical issues related to these topics. The meetings and hearings will be held at the National Institute of Standards and Technology in Gaithersburg, Md. Advance registration is required to attend the meeting. For further information, see

October Workshop Focuses on New Standard for Federal ID

The National Institute of Standards and Technology (NIST) will hold a public workshop Oct. 7 at the Hilton Washington DC North in Gaithersburg, Md., to discuss a new standard for secure and reliable forms of identification issued by the federal government to its employees and contractors. On Aug. 27, 2004, the White House issued a presidential directive calling for a mandatory, government-wide standard. (The directive is available at NIST will develop the standard as a Federal Information Processing Standard tentatively titled “Personal Identity Verification.” Topics to be discussed include verification of identity using fingerprint and facial images and personal identity verification systems architecture, components, algorithms, protocols and management. For further information and to register for the meeting, see

CD-ROM Trains Officials to Spot Scale/Meter Tampering

The National Institute of Standards and Technology (NIST) has just released a CD-ROM Audit Trail training course for weights and measure officials. Audit trails are mechanisms that many scale and meter manufacturers incorporate in their electronic weighing and measuring machines. Audit trails, commonly installed in gasoline pumps and supermarket scanner scales, are used to monitor changes to the machines that affect the accuracy of measurements. Weights and measure officials increasingly use audit trail data to spot tampering and fraudulent practices that hurt consumers and competing, but honest, merchants.

The CD-Rom includes narration, video and graphics to illustrate correct applications of weights and measure standards, explain the principles behind audit trail data acquisition and examples of how audit trail information is accessed on different types of weighing and measuring devices. The CD–ROM also includes interactive exercises that enable users to test their knowledge as they work through the course.

To obtain a free copy of the Audit Trail Device Security CD-Rom, contact NIST WMD, 100 Bureau Drive MS 2600, Gaithersburg, MD 20888-2600, (301) 975-4004, fax: (301) 926-0647, e-mail:

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Editor: Gail Porter

Date created:09/13/04
Date updated:09/14/04