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Search Publications by: Samuel P. Benz (Fed)

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Displaying 151 - 175 of 277

Measurement Time and Statistics for a Noise Thermometer With a Synthetic-Noise Reference

August 1, 2008
Author(s)
David R. White, Samuel Benz, J Labenski, Sae Woo Nam, Jifeng Qu, H Rogalla, Weston L. Tew
This paper describes methods for reducing the statistical uncertainty in measurements made by noise thermometers using digital cross correlators, and in particular, for thermometers using pseudorandom noise for the reference signal. First, a discrete

Systematic-Error Signals in the AC Josephson Voltage Standard: Measurement and Reduction

June 30, 2008
Author(s)
Regis Landim, Samuel P. Benz, Paul D. Dresselhaus, Charles J. Burroughs
We investigate the dominant frequency-dependent systematic error signals (SES) in the ac Josephson voltage standard. We describe our error measurement technique and a number of methods to reduce the errors. Most importantly we found that a small change in

Design of a Turn-Key 10 V Programmable Josephson Voltage Standard System

June 13, 2008
Author(s)
Paul D. Dresselhaus, Mike Elsbury, Charles J. Burroughs, David I. Olaya, Samuel P. Benz, Norman F. Bergren, Robert E. Schwall, Zoya Popovic
NIST is designing a 10 V Programmable Josephson Voltage Standard (PJVS) system with an improved microwave design and arrays of stacked NbXSi1-x-barrier Josephson junctions. For this new design a ?ground-up? approach, was used which takes into account all

Improvements in the NIST Johnson Noise Thermometry System

June 9, 2008
Author(s)
Samuel Benz, Horst Rogalla, Rod White, Jifeng Qu, Paul Dresselhaus, Wes L. Tew, Sae Woo Nam
We have developed a Johnson noise thermometry system that is calibrated by precision waveforms synthesized with a quantum-accurate voltage noise source (QVNS). Significant improvements to the QVNS and the cross-correlation measurement electronics have

Precision Differential Sampling Measurements of Low-Frequency Voltages Synthesized with an AC Programmable Josephson Voltage Standard

June 9, 2008
Author(s)
Alain Rufenacht, Charles J. Burroughs, Samuel P. Benz, Paul D. Dresselhaus, Bryan C. Waltrip, Thomas L. Nelson
Sampling is a promising technique to compare the stepwise-approximated sine waves synthesized by an AC Programmable Josephson Voltage Standard to the sinusoidal voltages of a secondary source at low frequencies (a few hundred Hz or less). This paper

Progress toward a 1V Pulse-Driven AC Josephson Voltage Standard

June 9, 2008
Author(s)
Samuel Benz, Paul Dresselhaus, Norman F. Bergren, Regis Landim
We present a new record output voltage of 275 mVrms, which is a 25% improvement over the maximum achieved with previous ac Josephson voltage standard circuits. We demonstrate operating margins for these circuits and use them to measure the harmonic

Thermal Voltage Converter Calibrations Using a Quantum AC Standard

April 10, 2008
Author(s)
Thomas E. Lipe Jr., Joseph R. Kinard Jr., Yi-hua D. Tang, Samuel Benz, Charles J. Burroughs, Paul Dresselhaus
We report on the first-ever use of a quantum ac source to calibrate a thermal transfer standard as part of the NIST calibration service for such devices, with reductions in calibration uncertainty of as much as an order of magnitude over traditional ac-dc

Development of a 60 Hz Power Standard using SNS Programmable Josephson Voltage Standards

April 7, 2008
Author(s)
Charles J. Burroughs, Samuel Benz, Paul Dresselhaus, Yonuk Chong, Bryan C. Waltrip, Thomas L. Nelson, J. Williams, D. Henderson, P. Patel, Luis Palafox, Ralf Behr
We are implementing a new standard for 60 Hz power based on precision sinusoidal reference voltages from two independent Programmable Josephson Voltage Standards (PJVS) (one for voltage and one for current). The NIST PJVS systems use series arrays of

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

ACJVS Operating Margins using a Ternary Arbitrary Bitstream Generator

June 22, 2007
Author(s)
Ernest Houtzager, Samuel Benz, Helko vanden Brom
In this paper we present measurements with a pulse-driven AC Josephson voltage standard (ACJVS) that uses a ternary arbitrary bitstream generator as the bias source. From these measurements we conclude that the circuit is operational for voltages up to 220

Design of SNS Josephson Arrays for High Voltage Applications

June 4, 2007
Author(s)
Paul Dresselhaus, Samuel Benz, Charles J. Burroughs, Norman F. Bergren, Yonuk Chong
The voltage from a single, microwave-biased Josephson junction is a small quantity; thus useful voltages are only generated through series arrays of many thousands of junctions. Arrays of superconductor-normal metal-superconductor junctions have been

Precision Measurements using a 300 mV Josephson Arbitrary Waveform Synthesizer

June 4, 2007
Author(s)
Samuel P. Benz, Paul D. Dresselhaus, Charles J. Burroughs, Norman F. Bergren
We have developed a Josephson Digital-to-Analog Converter, otherwise know as a Josephson Arbitrary Waveform Synthesizer, with 300 mV peak output voltage. This is the first system of its kind with demonstrated quantum accuracy. We will show precision

AC-DC Transfer Standard Measurements with an AC Josephson Voltage Standard

April 2, 2007
Author(s)
Samuel P. Benz, Charles J. Burroughs, Paul D. Dresselhaus, Norman F. Bergren, Thomas E. Lipe, Joseph R. Kinard Jr., Yi-hua Tang
In order to improve the NIST low-voltage calibration service for thermal voltage converters, we have constructed an ac Josephson voltage standard system that can synthesize accurate rms voltages up to 100 mV. Using this system, we synthesized dc voltages

Resistance-Based Scaling of LF-and MF-Band Thermal Noise Powers

April 1, 2007
Author(s)
John Labenski, Weston L. Tew, Sae Woo Nam, Samuel P. Benz, Paul D. Dresselhaus, Charles J. Burroughs
A conventional technique for scaling thermal noise power in Johnson Noise Thermometry (JNT) is via resistance ratios. We describe measurements in the low to medium frequency (LF/MF) bands using this approach via correlation methods in the frequency domain

Thermal Stability of Nb/a-NbxSi1-x/Nb Josephson Junctions

February 16, 2007
Author(s)
Burm Baek, Paul Dresselhaus, Samuel Benz
As a high resistivity normal metal barrier for superconducting Josephson junctions, metal-silicon alloys appear to be a good replacement for noble metals and have been applied to the development of quantum voltage standard circuits. We observed that the

Cosputtered Amorphous Nb_xSi_1-x Barriers for Josephson-Junction Circuits

December 1, 2006
Author(s)
Burm Baek, Paul D. Dresselhaus, Samuel P. Benz
Cosputtered Amorphous NbxSi1-x has been developed as a barrier material for Josephson junction array circuits. This material is not only promising as a normal-metal barrier for state-of-the-art Josephson voltage standard circuits, but the capability of

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

100 mV ac-dc Transfer Standard measurements with a Pulse-driven AC Josephson Voltage Standard

July 14, 2006
Author(s)
Samuel P. Benz, Charles J. Burroughs, Paul D. Dresselhaus, Thomas E. Lipe, Joseph R. Kinard Jr.
In order to improve the low-voltage calibration service at NIST we have constructed an ac Josephson voltage standard system with a maximum rms output voltage of 100 mV. Using this system we synthesized sinewaves of various audio frequencies and measured ac