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Displaying 226 - 250 of 425

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

Lumped 50 Ohm Arrays of SNS Josephson Junctions

December 1, 2006
Author(s)
Nicolas Hadacek, Paul Dresselhaus, Samuel Benz
For the first time lumped series arrays of Josephson junctions have been fabricated with a transmission line-matched 50 Ohm nresistance and having the thousands of junctions necessary to produce a metrologically significant voltage. Using such arrays we

Electrical Properties of Nb-MoSi2-Nb Josephson Junctions

June 6, 2005
Author(s)
Yonuk Chong, Paul Dresselhaus, Samuel Benz
We present a detailed study of the electrical properties of planar Nb-MoSi2-Nb Josephson junctions. The Nb-MoSi2-Nb junction is an excellent system to study proximity-coupling in junctions with rigid superconductor/normal metal boundaries by controlling

Practical High-Resolution Programmable Josephson Voltage Standards using Double- and Triple-Stacked MoSi 2 -Barrier Junctions

June 1, 2005
Author(s)
Yonuk Chong, Charles J. Burroughs, Paul Dresselhaus, Nicolas Hadacek, Hirotake Yamamori, Samuel Benz
We have developed vertically stacked superconductor-normal metal- superconductor Josephson junction technology for the next generation quantum voltage standards. Stacked junctions provide a practical way of increasing the output voltage and operating

Application of the Josephson Effect to Metrology

October 1, 2004
Author(s)
Samuel P. Benz, Clark Hamilton
The unique ability of a Josephson junction to control the flow of magnetic flux quanta leads to a perfect relationship between frequency and voltage. Over the last 30 years, metrology laboratories have used this effect to greatly improve the accuracy of dc

Double-stacked MoSi2-barrier junctions for programmable Josephson voltage standards

June 1, 2004
Author(s)
Yonuk Chong, Charles J. Burroughs, Paul D. Dresselhaus, Nicolas Hadacek, Hirotake Yamamori, Samuel P. Benz
We are developing MoSi2-barrier stacked junction arrays for Josephson voltage standards in order to increase the output voltage, operating bandwidth, and operating margins. In this paper we present results of a programmable voltage standard circuit with

More Diamagnetism Demonstrations

February 1, 2003
Author(s)
Chris Conery, Loren F. Goodrich, Theodore C. Stauffer
The availability of very strong permanent magnets allows observation of phenomena previously difficult to see. The diamagnetism of water and diamagneticly stabilized magnetic levitation are now easy to demonstrate.

Single-Cooper-Pair Transistors: Requirements for Robust 2e Periodicity

January 3, 2003
Author(s)
Joe Aumentado, Mark W. Keller, John M. Martinis
The superconducting analog of the single-electron transistor (SET), the single-Cooper-pair transistor (SCPT), is comprised of two ultrasmall tunnel junctions in series forming an island (see Figure 1(a)). Transport through the SCPT depends on the

Stacked Nanoscale Josephson Junction Arrays for High-Performance Voltage Standards

December 4, 2002
Author(s)
Samuel Benz, Paul Dresselhaus, Yonuk Chong, Charles J. Burroughs
Superconducting Josephson voltage standard systems have replaced electrochemical cell (battery-like) artifact standards for voltage metrology because quantum-based systems produce precise and accurate voltages independent of any material parameters. The

Refrigeration Methods for Superconductors

December 1, 2002
Author(s)
Ray Radebaugh
This chapter reviews various methods commonly used for achieving the cryogenic temperatures required of superconducting materials. The problems associated with cryogenic refrigerators (cryocoolers), such as poor reliability, low efficiency, electromagnetic

All-NbN Digital-to-Analog Converters for a Programmable Voltage Standard

November 21, 2001
Author(s)
Hirotake Yamamori, M. Itoh, H. Sasaki, A. Shoji, Samuel Benz, Paul Dresselhaus
Five-bit all-NbN digital-to-analog converters (DACs) for a programmable voltage standard have been fabricated using NbN/TiNx/NbN Josephson junctions and their operation has been demonstrated. The DAC consists of six arrays of 128, 128, 256, 512, 1024 and

Broadband Josephson Voltage Standards

May 20, 2001
Author(s)
Clark A. Hamilton, Samuel P. Benz
A Josephson junction is a perfect frequency to voltage converter, that is, V=f/K j where K j = 483597.9 GHz/V. This unique property has been used to convert a narrow (1 Hz) band 75 GHz reference frequency to a dc voltage standard. Josephson standards use

Coplanar Transmission Lines with Meandering Center Conductors in Y-Ba-Cu-O/Au Bilayers

June 1, 1999
Author(s)
C Weber, Ronald H. Ono, James Booth, Leila R. Vale, Samuel Benz, A. M. Klushin, H. Kohlstedt, R. Semerad
We have investigated both conventional and meandering coplanar microwave transmission lines patterned in Y-Ba-Cu-O/Au bilayers on yttria-stablized zirconia and sapphire substrates. Within the meandering waveguides, the gentre conductor was deformed from a

Operating Margins for a Superconducting Voltage Waveform Synthesizer

June 1, 1999
Author(s)
Samuel Benz, Clark A. Hamilton, Charles J. Burroughs
Operating margins for biolar superconducting voltage waveform synthesizer were measured. Current ranges were determined for 101 equally spaced dc voltage steps between - 18.6 and + 18.6 mV. The measured voltages of these steps deviated from the expected
Displaying 226 - 250 of 425