NIST Tech Beat - June 8, 2007

Researchers at the National Institute of Standards and Technology (NIST) have built a prototype high-speed quantum key distribution (QKD) system, based on a new detector system that achieves dramatically lower noise levels than similar systems. The new system, they say, can perform a theoretically unbreakable “one-time pad” encryption, transmission and decryption of a video signal in real-time over a distance of at least 10 kilometers.

Key distribution—the problem of ensuring that both the sender and receiver of an encrypted message (and no one else) share the same long string of random digits (the so-called “key”) used to encode and decode the message—has always been one of the most important challenges in cryptography. Since the 1980’s it’s been recognized that the unique properties of quantum mechanics—the fact that certain measurements cannot be made without altering the thing measured—offered the possibility of a system that could transmit as long a key as desired between two parties with no chance that it could be copied undetectably by a third party.

Since then the race has been on to build a fast, practical and reliable QKD system. One important requirement for any candidate system is that it be compatible with existing fiber-optic telecom networks that transmit at wavelengths of either 1550 or 1310 nanometers (nm) to reach the greatest distance. Another requirement is a highly efficient photon detector that can detect single photons reliably without introducing significant amounts of “noise.” One of the best low-noise detectors, a silicon-based avalanche photo diode (Si-APD), does not function at the telecom wavelengths. Instead, it operates best at much shorter wavelengths around 700 nm. To take advantage of the Si-APD, the NIST group designed a sub-system to “up-convert” single photons from a transmission wavelength of 1310 nm to 710 nm for high-efficiency detection.

Their QKD system that incorporates this up-conversion technique, described in a recent paper,* generates and transmits secure keys at a rate of over half a million bits per second over 10 km of optical fiber, fast enough to encrypt streaming digital video using one-time pad in real time. The group also has transmitted secure keys at rates near 10 kilobits per second at five times that distance. The same team last year set a speed record for transmission of secure keys over a kilometer of fiber (see www.nist.gov/public_affairs/releases/quantumfiber.htm). This work improves the distance by at least 10 times.

Advantages of the new system, according to the research team, include high speed, high efficiency, low noise and convenience of operation. The fact that it uses a 1310 nm transmission wavelength somewhat limits the propagation distance but adds the advantage that the parallel “classical-quantum” communication, which is needed for a full QKD system, can be realized in a single fiber without significant interference. Details of NIST’s up-conversion QKD research are available at http://w3.antd.nist.gov/quin.shtml.

* H. Xu, L. Ma, A. Mink, B. Hershman and X. Tang. 1310-nm quantum key distribution system with up-conversion pump wavelength at 1550 nm. Optics Express, Vol. 15, Issue 12, pp. 7247-7260.

National Institute of Standards and Technology (NIST) engineers are organizing the fourth in a series of Response Robot Evaluation Exercises for urban search and rescue (US&R) responders to be held on June 18-22, 2007, at Texas A&M’s “Disaster City” training facility in College Station, Texas. These events, sponsored by the Department of Homeland Security’s (DHS) Science and Technology Directorate, test robot performance on emerging standard test methods using actual training scenarios for emergency responders. The results will be used to refine the test methods, and in developing usage guides that match specific kinds of US&R robots to particular disaster scenarios.

This exercise will use two Disaster City training scenarios. A simulated structural collapse of a municipal building will allow responders to deploy robots to search for victims and assist in “rendering the structure safe” for responders to extricate those victims. This will require robots to face a variety of challenges as they traverse complex and confined spaces within the structure’s semi-collapsed walls, sloping floors, rubble and voids while searching for victims. The robots will be deploying high-tech sensors such as laser scanners to capture the size and shape of interior voids to help structural engineers set up shoring supports.

Responders also will use robots to investigate a “train wreck/derailment” involving a passenger train and an industrial HAZMAT tanker train carrying unknown substances. The unknown hazards of the incident will require emergency responders to direct work from a distance of 150 m (500 ft) initially. This scenario will require robots to traverse railroad tracks, wreckage and debris to map the scene, look in windows to locate victims, find hazardous leaks and identify tanker placards describing their contents. Some robots also may take samples of unknown substances for analysis, all while being remotely controlled from a safe distance. This exercise will focus on ground robots that are highly agile, human-portable, or even throwable, and robots that can circumnavigate a large area from a remote operator station. The robots will feature a variety of sensors, including color cameras, two-way audio transmitters, thermal imagers, chemical sensors, 3D mapping systems and GPS locators paired with geographic information systems (GIS).

Robot developers and vendors benefit from these exercises by learning firsthand what emergency responders need to perform their roles safely and effectively, and by getting feedback about their systems during mock deployments. The emergency responders benefit by getting to work with a wide variety of high-tech solutions within their own deployment scenarios and to guide robot developers toward answering their needs. Both communities will benefit from the emerging standard robot test methods being developed as a result of these exercise, which will provide a means of measuring and comparing robot performance to help responders understand the trade-offs of particular devices, and also help measure and compare operator proficiency in performing critical task through remote control interfaces.

This Response Robot Evaluation Exercise is locally hosted by the Texas A&M Engineering Extension Service and the Texas Federal Emergency Management Agency (FEMA) task force team (TX-TF1),

Scientists at the National Institute of Standards and Technology (NIST), along with colleagues at George Mason University and Kwangwoon University in Korea, have fabricated a memory device that combines silicon nanowires with a more traditional type of data-storage. Their hybrid structure may be more reliable than other nanowire-based memory devices recently built and more easily integrated into commercial applications.

As reported in a recent paper,* the device is a type of “non-volatile” memory, meaning stored information is not lost when the device is without power. So-called “flash” memory (used in digital camera memory cards, USB memory sticks, etc.) is a well-known example of electronic non-volatile memory. In this new device, nanowires are integrated with a higher-end type of non-volatile memory that is similar to flash, a layered structure known as semiconductor-oxide-nitride-oxide-semiconductor (SONOS) technology. The nanowires are positioned using a hands-off self-alignment technique, which could allow the production cost—and therefore the overall cost—of large-scale viable devices to be lower than flash memory cards, which require more complicated fabrication methods.

The researchers grew the nanowires onto a layered oxide-nitride-oxide substrate. Applying a positive voltage across the wires causes electrons in the wires to tunnel down into the substrate, charging it. A negative voltage causes the electrons to tunnel back up into the wires. This process is the key to the device’s memory function: when fully charged, each nanowire device stores a single bit of information, either a “0” or a “1” depending on the position of the electrons. When no voltage is present, the stored information can be read.

The device combines the excellent electronic properties of nanowires with established technology, and thus has several characteristics that make it very promising for applications in non-volatile memory. For example, it has simple read, write, and erase capabilities. It boasts a large memory window—the voltage range over which it stores information—which indicates good memory retention and a high resistance to disturbances from outside voltages. The device also has a large on/off current ratio, a property that allows the circuit to clearly distinguish between the “0” and “1” states.

Two advantages the NIST design may hold over alternative proposals for nanowire-based memory devices, the researchers say, are better stability at higher temperatures and easier integration into existing chip fabrication technology.

* Q. Li, X. Zhu, H. Xiong, S.-M. Koo, D.E. Ioannou, J. Kopanski, J.S. Suehle and C.A. Richter. Silicon nanowire on oxide/nitride/oxide for memory application. Nanotechnology 18 (2007) 235204.

Providing strong security for complex federal information systems is a challenging job. But now there’s a new version of a draft guide* for assessing the effectiveness of security of controls in federal information systems from the National Institute of Standards and Technology (NIST) that aims to make the job easier. The content of the new guide is expected to be incorporated into automated tools that support the information security programs of federal agencies.

The 387-page guide is designed to help information system owners and security managers ensure that appropriate computer security controls work as intended to protect information systems from being improperly accessed or compromised. NIST will accept comments on the draft document through July 31, 2007. Comments should be emailed to sec-cert@nist.gov or mailed to NIST at 100 Bureau Dr., M.S. 8930, Gaithersburg, Md. 20899-8930.

The guide is a companion document to NIST Special Publication 800-53, Minimum Security Controls for Federal Information Systems, which spells out the types of security controls such as user authentication, spam protection, cryptography and transmission confidentiality that must be used to protect federal information systems. The Federal Information Security Management Act (FISMA) of 2002 instructs NIST to prepare minimum computer security requirements for all federal information systems other than national security systems.

“The assessment requirements presented in this latest draft are intended to make compliance with FISMA easier, more efficient and ultimately to produce better computer and information security for the federal government,” noted NIST’s FISMA Implementation Project Leader Ron Ross.

* Guide for Assessing the Security Controls in Federal Information Systems: Building Effective Security Assessment Plans, (NIST SP 800-53A), June 2007, pp. 387.

Researchers at the National Institute of Standards and Technology (NIST) have developed two new calibration tools to help correct and validate the performance of analytic instruments that identify substances based on fluorescence.

Recent years have seen a significant increase in the development and use of fluorescence-based analytic techniques. Researchers can detect, measure and identify unknown substances—potentially including chemical and biological weapons—using spectroscopic techniques. In fluorescence spectroscopy, scientists send a beam of light at a certain wavelength into a sample, exciting electrons in particular analytes or fluorescent labels, which then emit light at longer wavelengths with measurable energy levels. This resulting spectral signature, recorded by a fluorescence spectrometer, is distinct for different fluorescent compounds. Many of these assays are being used in areas—including clinical diagnostics, environmental monitoring and drug development—where regulatory requirements are strict and may require standards for instrument qualification and method validation.

To meet these needs, NIST has developed two ready-to-use, fluorescent glass Standard Reference Materials (SRMs), about the size of a pack of a gum, whose certified values can be used to correct fluorescence emission spectra for relative intensity. SRM 2940 (“Orange emission”) has certified values for emission wavelengths from 500 to 800 nanometers when excited with light at 412 nm; SRM 2941 (“Green emission”) has certified values for emission wavelengths from 450 to 650 nm when excited with light at 427 nm.

To use SRM 2941 to calibrate a fluorescence spectrometer, for instance, investigators would excite the glass with light at 427 nm and collect the resulting fluorescence emission from 450 nm to 650 nm. Spectral correction factors for the instrument then could be determined by comparing the measured intensity values to the certified values. The fluorescence spectrum of any unknown sample taken on that instrument that emits from 450 nm to 650 nm then could be corrected to yield its true spectral shape. These standards also are resistant to photodegradation, making them good performance validation standards. Researchers can use them on a day-to-day basis to validate performance by simply measuring their fluorescence intensity under the same conditions, even for fluorescence instruments with non-tunable wavelength selectors, such as filter-based fluorometers and microscopes.

Standard Reference Materials are among the most widely distributed and used products from NIST. The agency prepares, analyzes and distributes more than 1300 different materials that are used throughout the world to check the accuracy of instruments and test procedures.

For more information on SRM 2940, “Relative Intensity Correction Std for Fluorescence Spectroscopy (Orange Emission) 412 nm,” see https://srmors.nist.gov/view_detail.cfm?srm=2940. For more information on SRM 2941, “Relative Intensity Correction Std for Fluorescence Spectroscopy (Green Emission) 427 nm,” see https://srmors.nist.gov/view_detail.cfm?srm=2941.

A new report from the National Institute of Standards and Technology (NIST) and the U.S. Environmental Protection Agency (EPA) offers building owners and managers information on retrofit options to improve the safety of buildings against airborne chemical and biological hazards. The new guide can be used to determine whether or not—and how—to harden existing buildings against accidental chemical releases or possible terrorist threats.

NIST researchers evaluated 14 alternative retrofit techniques based on data from simulated airflow and contaminant transport computer modeling as well as a case study in which retrofits were designed for a high-rise and single story building. In conjunction with the report, NIST also developed a life-cycle cost analysis tool for chemical and biological protection of buildings that helps building owners and managers to compare life-cycle costs of installation, operation and maintenance to determine the most cost-effective combination of retrofit options for their structure.

Retrofit options considered include enhanced particle filtration, sorbent-based gaseous air cleaning, ultraviolet germicidal irradiation, photocatalytic oxidative air cleaning, work area air capture and filtration equipment such as mail handling tables, ventilation system recommissioning, building envelope air-tightening, building pressurization, relocation of outdoor air intakes, shelter-in-place, isolation of vulnerable spaces such as lobbies, system shutdown and purge cycles, and automated heating, ventilating and air-conditioning (HVAC) operational changes in response to contaminant sensing.

Potential advantages, disadvantages and knowledge gaps are discussed for each technology. For example, the researchers note that filtration and air cleaning options have the advantage of being always in operation. But, as the report notes, their disadvantage is a current lack of standards for testing and rating gaseous air cleaning systems and other air cleaning approaches. The study also notes the potential for increased energy efficiency and improved indoor air quality results from various retrofit options, which could play a role in life-cycle cost comparisons of different strategies.

The analysis of retrofit strategies useful against chemical and biological building contamination and the development of software tools to select cost-effective ways to mitigate the hazards was performed under an Inter-Agency Agreement (IAG) with the EPA’s National Homeland Security Research Center, Decontamination and Consequence Management Division.

Eighty-four organizations have started down the path they hope will lead to their being honored with the 2007 Malcolm Baldrige National Quality Award, the nation’s highest recognition for excellence. Applicants include two manufacturers, four service companies, seven small businesses, 16 educational organizations, 42 health care organizations -- and in a category in which the Presidential award may be given for the first time—13 nonprofits/governmental organizations.

The 84 applicants will be evaluated rigorously by an independent board of examiners in seven areas: leadership; strategic planning; customer and market focus; measurement, analysis and knowledge management; workforce focus; process management; and results. Examiners provide each applicant with a wealth of feedback on strengths and opportunities for improvement.

Named after Malcolm Baldrige, the 26th Secretary of Commerce, the Baldrige Award was established by Congress in 1987. The award promotes excellence in organizational performance, recognizes the achievements and results of U.S. organizations, and publicizes successful performance strategies. The award is not given for specific products or services. Since 1988, 67 organizations have received Baldrige Awards.

Postdoctoral fellows currently working in the Greater Washington, D.C., area have a unique opportunity to advance their research careers at the Second Annual Post-Doc Conference: Access to STEM (Science, Technology, Engineering and Mathematics) Talent being held on June 27, 2007, at the Gaithersburg, Md., headquarters of the National Institute of Standards and Technology (NIST).

Rockville Economic Development Inc. and the Tech Council of Maryland are hosting the conference with NIST.

The conference will introduce young Ph.D. researchers to career possibilities in industry, government agencies and non-profits, as well as entrepreneurial opportunities, in the Greater D.C. area. A job fair showcasing local companies looking for Ph.D. talent, résumé reviews by human resources professionals, and access to immigration attorneys also will be offered.

Due to NIST security regulations, registration for the conference will close at 5 p.m. Eastern Daylight Time on June 20, 2007. No walk-ins will be allowed. Registration is limited to those who are currently doing post-doctoral work in a Greater D.C. area federal agency or academic institution. Post-docs must submit a copy of their résumé when registering.

Three scientists from the National Institute of Standards and Technology (NIST) were among the eight federal employees who received the Arthur S. Flemming Award in ceremonies held June 4 at George Washington University. The Flemming Awards honor those with three to 15 years of public service experience for extraordinary contributions to the federal government.

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Editor: Michael Baum

Date created: June 8, 2007
Date updated: June 8, 2007
Contact: inquiries@nist.gov