Polarizability of Helium and Gas Metrology

Journal Article · Fri Jun 22 00:00:00 EDT 2007 · Physical Review Letters

DOI:https://doi.org/10.1103/PHYSREVLETT.98.254504· OSTI ID:20953311

Schmidt, J W; Moldover, M R ^[1]; Gavioso, R M ^[2]; May, E F ^[3]

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1. Process Measurements Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-8360 (United States)
2. Istituto Nazionale di Ricerca Metrologica, Turin 10135 (Italy)
3. School of Oil and Gas Engineering, University of Western Australia, Perth 6009 (Australia)

Using a quasispherical, microwave cavity resonator, we measured the refractive index of helium to deduce its molar polarizability A{sub {epsilon}} in the limit of zero density. We obtained (A{sub {epsilon}}{sub ,meas}-A{sub {epsilon}}{sub ,theory})/A{sub {epsilon}}=(-1.8{+-}9.1)x10= {sup -6}, where the standard uncertainty (9.1 ppm) is a factor of 3.3 smaller than that of the best previous measurement. If the theoretical value of A{sub {epsilon}} is accepted, these data determine a value for the Boltzmann constant that is only 1.8{+-}9.1 ppm larger than the accepted value. Our techniques will enable a helium-based pressure standard and measurements of thermodynamic temperatures.

• OSTI ID: 20953311
• Journal Information: Physical Review Letters, Vol. 98, Issue 25; Other Information: DOI: 10.1103/PhysRevLett.98.254504; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0031-9007
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CAVITY RESONATORS
HELIUM
MICROWAVE RADIATION
POLARIZABILITY
REFRACTIVE INDEX