NCSLI Meeting Agenda - Monday - May 20, 2019

Time Topic Speaker
8:00 AM - 8:30 AM Registration  
8:30 AM - 8:45 AM Orientation and Introduction Mike Duncan
8:45 AM - 9:15 AM History and Current Research at ORNL Kim Jeskie
9:15 AM - 10:00 AM The Revised SI (vol. 1) and the Redefinition of the Kilogram Leon Chao - NIST
  Abstract: On May 20, 2019, World Metrology Day, the International System of Units (SI) will undergo a paradigm shift from a set of seven base units to a set of seven base fundamental constants. This talk will highlight the evolution of metrology and three of seven SI units/constants (kilogram, meter, second) with an emphasis on the redefinition of the kilogram in terms of a fixed value of the Planck constant, h, using an instrument called a Kibble balance.
10:00 AM - 10:20 AM Break  
10:20 AM - 11:05 AM The Revised System (vol. 2) and Dissemination of the Ohm Alireza Panna-NIST
  Abstract: The redefinition and consequently the revision to the present International System of Units (SI) heralds a new era in measurement which will be traceable to fundamental constants. This talk will briefly describe the revisions made to four of seven SI units (kelvin, mole, candela, and ampere) and its implications. The impact to electrical metrology in terms of the SI derived units of electric potential difference and electric resistance will be presented with an emphasis on resistance. Finally, a description of various scaling techniques to decade resistance levels based on both cryogenic and non-cryogenic current comparator bridges will be presented along with a discussion of the advantages of various scaling paths to describe the dissemination of the Ohm in the revised SI.
11:05 AM - 11:50 AM Graphene based table-top Quantum Hall Resistance Standard Shamith Payagala-NIST
  Abstract: At present, most QHR standards are based on AlGaAs/GaAs heterostructures and rely on the integer quantum Hall effect (QHE) as the foundation for traceability of the ohm (SI unit). Although the effect is well-tested, accessing the QHR with an uncertainty near one part in 109 requires cumbersome and expensive infrastructure to reach low temperatures (0.3 K to 1.6 K) and high magnetic fields (6 T to 12 T), ultimately limiting the efficiency of calibrations and traceability. Graphene, the two-dimensional, honeycomb lattice of carbon atoms, exhibits the QHE at higher temperatures (4 K) and lower magnetic fields (5 T) than in gallium arsenide (GaAs), allowing the operation of epitaxial graphene (EG) QHR devices in cryogen-free refrigeration systems fitted with compact superconducting magnets. This concept motivates research in optimizing EG devices for metrology to promote accessibility to the QHR. Versatility and low operating cost facilitate graphene based QHR systems to be used in metrology labs beyond National Metrology Institutes (NMIs) and a handful of industrial laboratories. We have demonstrated that EG devices can potentially be used up to 10 V, where the precision of DCC room-temperature bridges can provide turn-key resistance traceability for the most demanding applications with a relative uncertainty of 10-8.
11:50 AM - 12:05 PM Picture  
12:05 PM - 1:05 PM Lunch  
1:05 PM - 1:50 PM Current and Future States of Realization of the SI Units at ORNL Greg Strickland, Joe Keck, Brian Sizemore, Chandler Hinton
  Abstract: The ORNL Metrology Laboratory currently realizes SI units by a combination of natural constants and physical artifacts. Staff from the ORNL Metrology lab will provide a brief discussion of the current state of realization of the SI units and how those units are realized. Also discussed will be future plans to realize the SI units, currently realized using physical artifacts, non-artifact-based techniques, including recent efforts to realize the kilogram using natural constants.
1:50 PM - 2:05 PM Tour Instructions and Closing Mike Duncan
2:05 PM - 3:35 PM Tour of ORNL Metrology Labs  
     
     
ORNL Public | Disclaimer | Comments