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Search Publications by: Dean G. Jarrett (Fed)

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Displaying 26 - 50 of 178

Graphene Quantum Hall Effect Parallel Resistance Arrays

February 2, 2021
Author(s)
Alireza Panna, I Fan Hu, Mattias Kruskopf, Dinesh K. Patel, Dean G. Jarrett, Chieh-I Liu, Shamith Payagala, Dipanjan Saha, Albert Rigosi, David B. Newell, Chi-Te Liang, Randolph Elmquist
As first recognized in 2010, epitaxial graphene on SiC(0001) provides a platform for quantized Hall resistance (QHR) metrology unmatched by other 2D structures and materials. Here we report graphene parallel QHR arrays, with metrologically precise

The Next Generation of Current Measurement for Ionization Chambers

September 1, 2020
Author(s)
Ryan P. Fitzgerald, Denis E. Bergeron, Dean G. Jarrett, Neil M. Zimmerman, Carine Michotte, Hansjoerg Scherer, Stephen Giblin, Steven Judge
Re-entrant ionization chambers (ICs) are essential to radionuclide metrology and nuclear medicine for maintaining standards and measuring half-lives. Metrology-quality systems must be precise and stable to 0.1% over many years, and linear from 10^(-14) A

AC and DC Quantized Hall Array Resistance Standards

August 28, 2020
Author(s)
Randolph E. Elmquist, Mattias Kruskopf, Dinesh K. Patel, I Fan Hu, Chieh-I Liu, Albert F. Rigosi, Alireza R. Panna, Shamith U. Payagala, Dean G. Jarrett
Quantized Hall array resistance standards (QHARS) span values from 100 (ohm) to 1 M(ohm) and demonstrate precision approaching that of single devices. This paper focuses on QHARS having values near 1 k(ohm) for increased sensitivity using room-temperature

Evaluation of an alternative null detector for adapted Wheatstone bridge

August 24, 2020
Author(s)
Shamith U. Payagala, Alana M. Dee, Dean G. Jarrett
The adapted Wheatstone bridge technique has been utilized at National Institute of Standards and Technology (NIST) and other National Metrology Institutes (NMIs) for high resistance measurements. In this work, we evaluate the suitability of a

Evaluation of NMIJ Traveling Dual Source Bridge Using NIST Adapted Wheatstone Bridge

August 24, 2020
Author(s)
Takehiko Oe, Shamith U. Payagala, Dean G. Jarrett, Nobu-Hisa Kaneko
DC high resistance measurement capability has been evaluated using a NMIJ traveling dual source bridge between NIST and NMIJ. The NMIJ bridge determines the resistance ratio by measuring the voltage ratio using a digital multimeter, 3458A. Based on the

Ohms Law Low-current Calibration System for Ionization Chambers

August 24, 2020
Author(s)
Dean G. Jarrett, Shamith U. Payagala, Ryan P. Fitzgerald, Denis E. Bergeron, Jeffrey T. Cessna, Charles J. Waduwarage Perera, Neil M. Zimmerman
A system for the calibration of electrometers that measure currents from ionization chambers is described. The calibration system uses a 1 GΩ standard resistor in series with a stable voltage source to generate calibration currents from 1 pA to 20 nA

Advanced Temperature-Control Chamber for Resistance Standards

April 10, 2020
Author(s)
Shamith Payagala, Alireza Panna, Albert Rigosi, Dean G. Jarrett
Calibration services for resistance metrology have continued to advance their capabilities and establish new and improved methods for maintaining standard resistors. Despite the high quality of these methods, there still exist inherent limitations to the