Resistance standards traceable to NIST provide references for measurements of current at levels from 3000 A to below 20 fA and are used to support a wide variety of impedance, temperature, strain, and power measurements. This project develops the technology of quantum electrical measurements including the world's best high resistance standards and superconducting quantum interference device (SQUID) based scaling techniques. We have maintained close working relationships with researchers in other leading national institutes and successfully completed bilateral and key comparisons with the Bureau International des Poids et Measures (BIPM) and other National Metrology Institutes (NMI), serving as the pilot laboratory for several of these comparisons. This leadership has resulted in collaborative research on cryogenic current comparators (CCCs) and improved resistance standards, development of low current and high current measurement techniques for reduced uncertainty of measurements based on resistance metrology, and staff being called upon to provide expert peer review of NMIs and evaluating other labs while performing resistance and current comparisons.
The Metrology of the Ohm Project has been a leader in providing internationally consistent resistance standards that are readily available to support the scientific and industrial foundations of the U.S. economy. Through this very broad customer base, the activities of the project enable cost-effective electrical measurements at NIST and at more than 250 U.S. sites, leading to improved performance of products and services in a competitive world environment. The resistance calibration service brings a yearly income to NIST of several hundred thousands of dollars as well as supporting over a dozen other calibration areas. Project staff provide extensive customer contact and consultation on topics including low current measurements (for photodetectors, aerosol electrometers, ionizing radiation measurements) the characterization processes used with resistive shunts at very high current levels, and power loading measurements. Project scientists work in the U.S. and international communities, including support for comparisons at low, moderate, and high resistance levels and development of improved standards and techniques for better agreement between primary references.
The project collaborates in research on low current measurements, ac impedance, and active participation with the Quantum Conductance project that aims to develop quantum Hall resistance (QHR) devices from graphene. We provide ongoing support for the electronic kilogram experiment as well as pursuing scientific breakthroughs to maintain accurate local representations of the unit (conventional standards) and to develop improved quantum metrology, such as the introduction of resistive-winding cryogenic current comparators (CCCs) that enable stable SQUID operation with improved current sensitivity.
Graphene Quantum Hall Effect Parallel Resistance Arrays
Published February 2, 2021 in Physical Review B
Alireza R. Panna, I Fan Hu, Mattias Kruskopf, Dinesh K. Patel, Dean G. Jarrett, Chieh-I Liu, Shamith U. Payagala, Dipanjan Saha, David Newell, Chi-Te Liang, Randolph Elmquist, Albert Rigosi
Comparison between Graphene and GaAs Quantized Hall Devices with a Dual Probe
Published July 31, 2020 in IEEE Transactions on Instrumentation and Measurement
Shamith U. Payagala, Albert F. Rigosi, Alireza R. Panna, Alessio Pollarolo, Mattias Kruskopf, Stephan Schlamminger, Dean G. Jarrett, Ryan Brown, Randolph E. Elmquist, Duane Brown, David B. Newell
Advanced Temperature-Control Chamber for Resistance Standards
Published April 10, 2020 in NIST Journal of Research
Shamith U. Payagala, Alireza R. Panna, Albert F. Rigosi, Dean G. Jarrett
Comparison of Multiple Methods for Obtaining PΩ Resistances with Low Uncertainties
Published September 3, 2019 in IEEE Transactions on Instrumentation and Measurement
Kwang Min Yu, Dean G. Jarrett, Albert F. Rigosi, Shamith U. Payagala, Marlin E. Kraft
Graphene Devices for Table-Top and High Current Quantized Hall Resistance Standards
Published December 10, 2018 in IEEE Transactions on Instrumentation and Measurement
Albert F. Rigosi, Alireza R. Panna, Shamith U. Payagala, Mattias Kruskopf, Marlin E. Kraft, George R. Jones Jr., Bi Y. Wu, Hsin Y. Lee, Yanfei Yang, Jiuning Hu, Dean G. Jarrett, David B. Newell, Randolph E. Elmquist