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Displaying 31426 - 31450 of 73929

An Optical System for Body Imaging from a Distance Using near-TeraHertz Frequencies

January 26, 2008
Author(s)
William Duncan, Robert E. Schwall, Kent D. Irwin, James A. Beall, Carl D. Reintsema, W.Bertrand (Randy) Doriese, Hsiao-Mei Cho, Brian Estey, Goutam Chattopadhyay, Peter Ade, Carole Tucker
We present the outline of the optical design of a TeraHertz (THz) imager for the detection of shrapnel-loaded improvised explosive devices (IED''s) at ''stand-off'' distances of 14 - 26 meters. The system will use 4 antenna-coupled TES detector arrays of

Analysis of Nuclear Material by Alpha Spectroscopy with a Transition-Edge Microcalorimeter

January 26, 2008
Author(s)
Rob Horansky, Joel Ullom, James A. Beall, Gene C. Hilton, Kent D. Irwin, Leila R. Vale, Don Dry, Stephen Lamont, Clifford R. Rudy, Michael W. Rabin
We present measurements from a cryogenic microcalorimeter designed to detect alpha particles. The enhanced resolution of microcalorimeter alpha detectors will provide new capabilities for actinide analysis. We demonstrate a spectral resolution of 2.4 keV

A TDMA Hybrid SQUID Multiplexer

January 25, 2008
Author(s)
Carl D. Reintsema, James A. Beall, W.Bertrand (Randy) Doriese, William Duncan, S. L. Ferreira, Gene C. Hilton, Kent D. Irwin, Dan Schmidt, Joel Ullom, Leila R. Vale, Yizi Xu
We have developed a multiplexed read-out for transition edge sensors based on a hybrid time- and frequency-domain basis set, similar to that used in time-division multiple-access (TDMA) mobile phones. The hybrid basis set uses bandwidth more efficiently

Characterization of 26 miniSTR loci for improved analysis of degraded DNA samples

January 25, 2008
Author(s)
Carolyn R. Steffen, Margaret C. Kline, Michael Coble, John M. Butler
An additional 20 novel mini-short tandem repeat (miniSTR) loci have been developed and characterized to aid in the analysis of degraded DNA samples. These new markers produce short PCR products in the target range of 50 150 base pairs (bp) by moving the

Determination of Work Functions in the Ta 1-x Al x N y /HfO 2 Advanced Gate Stack Using Combinatorial Methodology

January 24, 2008
Author(s)
Kao-Shuo Chang, Martin L. Green, Jason Hattrick-Simpers, John S. Suehle, Ichiro Takeuchi, Ozgur Celik, S De Gendt
Combinatorial methodology enables the generation of comprehensive and uniform samples, and therefore data sets, compared to the one-composition-at-a-time approach. We demonstrate the efficacy of combinatorial methodology applied to Ta1-xAlxNy alloys as

Hydrogenization of Zr 0.9 Ti 0.1 Cr x Fe 2-x Intermetallic Compounds: Free Electron Model for Magnetic Susceptibility and Thermoelectric Power

January 24, 2008
Author(s)
S. Niyomsoan, P. Termsuksawad, Ronald B. Goldfarb, David Olson, B. Mishra, Z Gavra, V I. Kaydanov
The magnetic susceptibility and thermoelectric power of Zr 0.9Ti 0.1Cr xFe 2-x intermetallic compounds were investigated as functions of hydrogen content. The alloys are all paramagnetic, with magnetic susceptibility and Seebeck coefficient increasing with

Large array of multiplexed gamma-ray microcalorimeters for nuclear-materials analysis

January 24, 2008
Author(s)
W.Bertrand (Randy) Doriese, Joel Ullom, James A. Beall, William Duncan, S. L. Ferreira, Gene C. Hilton, Rob Horansky, Kent D. Irwin, John Mates, Carl D. Reintsema, Dan Schmidt, Leila R. Vale, Yizi Xu, Barry L. Zink, Michael W. Rabin, Minesh K. Bacrania, Stephen Lamont, Andrew Hoover, Clifford R. Rudy, Duc Vo, C. K. Stahle, Kevin R. Boyce, Larry E. Brown, Jonathan M. King, F. S. Porter
We are developing a gamma-ray spectrometer for the analysis of nuclear materials based on an array of superconducting transition-edge-sensor microcalorimeters. The instrument includes eight columns of time-division-SQUID multiplexing circuitry capable of

Materials Analysis with Cryogenic Sensors

January 24, 2008
Author(s)
Joel N. Ullom
Low temperature photon detectors are increasingly attractive tools for materials analysis. Their range of applications has broadened from early work on x-ray fluorescence and now spans the electromagnetic spectrum from terahertz to gamma-ray energies. In

Combinatorial Methodology for the Exploration of Metal Gate Electrodes on HfO 2 for the Advanced Gate Stack

January 23, 2008
Author(s)
Kao-Shuo Chang, Martin L. Green, John S. Suehle, Jason Hattrick-Simpers, Ichiro Takeuchi, K Ohmori, T Chikyow, S De Gendt, Prashant Majhi
Combinatorial methodology offers an efficient platform to accelerate the exploration of new materials. We demonstrate the effectiveness of this technique on the study of new metal gates for the advanced gate stack. We report two examples, Ni-Ti-Pt ternary

Moving Toward Semantic Interoperability of Medical Devices

January 22, 2008
Author(s)
John J. Garguilo, Sandra I. Martinez, Richard M. Rivello, Maria Cherkaoui
NIST researchers are collaborating with medical device experts to facilitate the development and adoption of standards for medical device communications throughout the healthcare enterprise as well as integrating it into the electronic health record. NIST

Operation of an X-ray transition-edge sensor cooled by tunnel junction refrigerators

January 19, 2008
Author(s)
Nathan A. Tomlin, James A. Beall, Gene C. Hilton, Kent D. Irwin, Galen O'Neil, Dan Schmidt, Leila R. Vale, Joel Ullom
We demonstrate successful cooling of an X-ray transition-edge sensor (TES) using solid-state refrigerators based on normal-metal/insulator/superconductor (NIS) tunnel junctions. Above the TES transition temperature (Tc), we use Johnson noise thermometry to

256-Channel Magnetic Imaging System

January 18, 2008
Author(s)
Fabio C. da Silva, Sean Halloran, Anthony B. Kos, David P. Pappas
We present the design and fabrication of a magentoresistive imaging system capable of measuring 256 channels simultaneously along linear ranges of 4 mm and 13 mm. The channels are interfaced by custom electronics and the images are displayed in real time

Constraints on a Synthetic-Noise Source for Johnson Noise Thermometry

January 18, 2008
Author(s)
David R. White, Samuel Benz
Conventional Johnson noise thermometers based on switching correlators have conflicting matching requirements for the sensing resistance. To mitigate distortion effects in the correlator, the RT products of the two sensors must be the same, and to mitigate

Current Status of the Quantum Metrology Triangle

January 18, 2008
Author(s)
Mark W. Keller
The quantum metrology triangle is a test of the consistency of three quantum electrical standards: the single-electron tunneling current standard, the Josephson voltage standard, and the quantum Hall resistance standard. This paper considers what is known

Demonstration of a Multiplexer of Dissipationless SQUIDs}

January 18, 2008
Author(s)
John Mates, Gene C. Hilton, Kent D. Irwin, Leila R. Vale, Konrad Lehnert
We report on the development of a microwave SQUID multiplexer for reading out arrays of low-temperature detectors. In this frequency-division multiplexer, each SQUID couples to a high-Q superconducting resonator so that flux through the SQUID shifts the

The Modified-Single Fiber Test: A Methodology for Monitoring Ballistic Performance

January 18, 2008
Author(s)
Jae Hyun Kim, Walter G. McDonough, William R. Blair, Gale A. Holmes
In an effort to develop a minimally invasive testing methodology for monitoring the in-service performance of soft body armor, the ASTM D3379-75 standard was modified by measuring the fiber diameter at 5 equally spaced locations along a 6 cm gauge length

Overcoming Impediments to Cell Phone Forensics

January 16, 2008
Author(s)
Wayne Jansen, Aurelien M. Delaitre, Ludovic Moenner
Cell phones are an emerging but rapidly growing area of computer forensics. While cell phones are becoming more like desktop computers functionally, their organization and operation are quite different in certain areas. For example, most cell phones do not

256-channel magnetic imaging system

January 15, 2008
Author(s)
Fabio C. Da Silva, Sean Halloran, Anthony B. Kos, David P. Pappas
We present the design and fabrication of a magnetoresistive imaging system capable of scanning 256 channels simultaneously along linear ranges of either 4 or 13 mm. High speed electronics read the channels and transfer the data to a computer that builds

A Weighted GCV Method for Lanczos Hybrid Regularization

January 15, 2008
Author(s)
Julianne Chung, James G. Nagy, Dianne M. O'Leary
Lanczos-hybrid regularization methods have been proposed as effective approaches for solving large-scale ill-posed inverse problems. Lanczos methods restrict the solution to lie in a Krylov subspace, but they are hindered by semi-convergence behavior, in
Displaying 31426 - 31450 of 73929
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