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Metrology

Electrical / electromagnetic metrology

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Displaying 151 - 175 of 470

Measurement of the Planck constant at the National Institute of Standards and Technology from 2015 to 2017

July 28, 2017
Author(s)
Darine El Haddad, Frank Seifert, Leon Chao, Antonio Possolo, David B. Newell, Jon R. Pratt, Carl J. Williams, Stephan Schlamminger
Researchers at the National Institute of Standards and Technology(NIST) estimate the value of the Planck constant as h = 6.62606994(10) x 10^-34 Js, hence with relative standard uncertainty 15.3 x 10^-9. This measurement result is based on over 17,000

An improved electronic measurement of the Boltzmann constant by Johnson noise thermometry

July 18, 2017
Author(s)
Jifeng Qu, Samuel Benz, Kevin Coakley, Horst Rogalla, Weston L. Tew, David R. White, Kunli Zhou, Zhenyu Zhou
Recent measurements using acoustic gas thermometry have determined the value of the Boltzmann constant, k, with a relative uncertainty less than 110-6. These results have been supported by a measurement with a relative uncertainty of 1.910-6 made with

A Review of the IEEE 1785 Standards for Rectangular Waveguides above 110 GHz

June 6, 2017
Author(s)
Ronald A. Ginley, Nick M. Ridler
A new series of standards has recently been published by IEEE defining waveguide for use at millimeter-wave and terahertz frequencies. The series comprises three standards covering different aspects of this technology: (i) frequency bands and waveguide

Comprehensive circuit model of auto-limiting superconductor devices and systems

May 31, 2017
Author(s)
Jordi Mateu, C Collado, A Hueltes, D Garcia-Pastor, R Perera, Nikhil M. Joshi, Xifeng Lu, Nate Orloff, Jim Booth
This paper presents a phenomenological equivalent circuit to model the phenomenon occurring when a section of superconducting transmission line transits from the superconductor to the normal state. This phenomenon allows the use of superconductors for the

3-Port Frequency Selective Absorptive Limiter

May 1, 2017
Author(s)
A Hueltes, Eduard Rocas, Carlos Collado, Jordi Mateu, D Garcia-Pastor, James Booth, Rafael P. Robles
This paper proposes a novel 3-port absorptive limiter for frequency selective circuits based on a similar configuration than a conventional 90º hybrid coupler. This circuit uses the switching features existing in common diode devices to changes between the

Validation of Robotics for Antenna Measurements

March 18, 2017
Author(s)
Jeffrey R. Guerrieri
This paper presents recent measurements using the newly developed Configurable Robotic Millimeter-Wave Antenna (CROMMA) facility by the Antenna Metrology Lab at the National Institute of Standards and Technology (NIST). NIST set out to develop an antenna

Insulator-quantum Hall transition in monolayer epitaxial graphene

July 22, 2016
Author(s)
Lung-I Huang, Yanfei Yang, Randolph Elmquist, Shun-Tsung Lo, Fan-Hung H. Liu, Chi-Te Laing
We report on magneto-transport measurements on low-density, large-area monolayer epitaxial graphene devices grown on SiC. We observe temperature (T)-independent crossing points in the longitudinal resistivity (rho)sub(xx), which are signatures of the

10 Volt Automated Direct Comparison of Two Cryocooled Programmable Josephson Voltage Standards

July 9, 2016
Author(s)
Alain Rufenacht, Yi-hua D. Tang, Paul Dresselhaus, Charles J. Burroughs, Robert E. Schwall, Samuel P. Benz
We have performed direct dc comparisons between two cryocooled 10 V programmable Josephson voltage standards utilizing an automated synchronization scheme for the voltage reversals, which enables the use of a high sensitivity null detector on its 3 µV

Direct comparison of a Pulse-driven Josephson Arbitrary Waveform Synthesizer and a Programmable Josephson Voltage Standard at 1 Volt

July 9, 2016
Author(s)
Alain Rufenacht, Nathan Flowers-Jacobs, Anna Fox, Charles J. Burroughs, Paul Dresselhaus, Samuel P. Benz
We have performed direct ac comparisons between two types of quantum voltage standards, a pulse- driven Josephson arbitrary waveform synthesizer and a programmable Josephson voltage standard, at 1 V rms amplitude and a frequency of 100 Hz. The system

Josephson-Based Full Digital Bridge for High-Accuracy Impedance Comparisons

July 9, 2016
Author(s)
Frederic Overney, Nathan Flowers-Jacobs, Blaise Jeanneret, Alain Rufenacht, Anna Fox, Jason Underwood, Andrew D. Koffman, Samuel P. Benz
This paper describes a Josephson-based impedance bridge capable of comparing any types of impedance over a large bandwidth. The heart of the bridge is a dual AC Josephson Voltage Standards (ACJVS) source which offers unprecedented flexibility in high

Simultaneous Double Waveform Synthesis with a Single Programmable Josephson Voltage Standard

July 9, 2016
Author(s)
Alain Rufenacht, Anna Fox, Paul Dresselhaus, Charles J. Burroughs, Samuel P. Benz, Bryan C. Waltrip, Thomas L. Nelson
We have recently demonstrated new 2 V PJVS devices configured with two voltage outputs and two sets of least significant bits in order to simultaneously generate two independent stepwise output waveforms. This development improves upon our previous

Josephson-Based Full Digital Bridge for High-Accuracy Impedance Comparisons

June 24, 2016
Author(s)
Frederic Overney, Nathan Flowers-Jacobs, Blaise Jeanneret, Alain Rufenacht, Anna Fox, Jason Underwood, Andrew D. Koffman, Samuel P. Benz
This paper describes a Josephson-based full digital impedance bridge capable of comparing any two impedances, regardless of type (R-C, R-L, or L-C), over a large frequency range. At the heart of the bridge are two Josephson arbitrary waveform synthesizer

Edge-state Transport in Graphene p-n Junctions in the Quantum Hall Regime

December 7, 2015
Author(s)
Nikolai Klimov, Son T. Le, Jun Yan, Pratik Agnihotri, Everett Comfort, Ji Ung Lee, David B. Newell, Curt A. Richter
We experimentally investigate charge carrier transport in a graphene p-n junction device by using independent p-type and n-type electrostatic gating which allow full characterization of the junction interface in the quantum Hall regime covering a wide

Quantized Hall resistance in large-scale monolayer graphene

November 28, 2015
Author(s)
Yanfei Yang, Chiashain Chuang, Chieh W. Liu, Randolph Elmquist
Abstract: Graphene is an atomic-thickness carbon lattice that can be exfoliated from solid graphite or grown using high temperature processing methods on a variety of substrates. Many practical applications of large-area graphene, however, are limited by

First measurements of the flux integral with the new NIST-4 watt balance

March 31, 2015
Author(s)
Darine El Haddad, Frank Seifert, Leon Chao, Yusi A. Cao, Georgio A. Sineriz, Jon R. Pratt, David B. Newell, Stephan Schlamminger
In early 2014, construction of a new watt balance, named NIST-4, has started at the National Institute of Standards and Technology (NIST). In a watt balance, similar to a mass comparator, the gravitational force of an unknown mass is compensated by an

Cryocooled 10 V Programmable Josephson Voltage Standard

December 11, 2014
Author(s)
Alain Rufenacht, Logan A. Howe, Anna Fox, Robert E. Schwall, Paul Dresselhaus, Charles J. Burroughs, Samuel Benz
Implementation of programmable Josephson voltage standard (PJVS) circuits on cryocooler at 4 K is a challenge. The limited cooling power of the cryocoolers has to balance the heat dissipated by the PJVS circuit in order to maintain a stable temperature

NIST 10 V Programmable Josephson Voltage Standard System Using a Low Capacity Cryocooler

November 6, 2014
Author(s)
Logan A. Howe, Anna Fox, Alain Rufenacht, Charles J. Burroughs, Paul Dresselhaus, Samuel Benz, Robert E. Schwall
Rising costs of and difficulty in obtaining liquid helium in many areas of the world provides strong motivation for cryogen-free operation of superconducting devices such as NIST Programmable Josephson Voltage Standard (PJVS) systems. However, operation on

Alignment and testing of the NIST Calculable Capacitor

August 24, 2014
Author(s)
Yicheng Wang, Felipe Guzman, Corey A. Stambaugh, Radek Smid, Hugo Zuniga Calvo, Andrew Koffman, Jon Pratt, John Lawall
This paper reports progress on the NIST effort to develop a new calculable capacitor, focusing on improvement of the guard electrode motion control as well as issues associated with the overall electrode alignment. Design of a multi-wavelength Fabry-Perot
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