TY - JOUR
T1 - Polarizability of Helium and Gas Metrology
AU - Schmidt, JW
AU - Gavioso, RM
AU - May, Eric
AU - Moldover, MR
PY - 2007
Y1 - 2007
N2 - Using a quasispherical, microwave cavity resonator, we measured the refractive index of helium to deduce its molar polarizability A(epsilon) in the limit of zero density. We obtained (A(epsilon,meas)-A(epsilon,theory))/A(epsilon)=(-1.8 +/- 9.1)x10(-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(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.
AB - Using a quasispherical, microwave cavity resonator, we measured the refractive index of helium to deduce its molar polarizability A(epsilon) in the limit of zero density. We obtained (A(epsilon,meas)-A(epsilon,theory))/A(epsilon)=(-1.8 +/- 9.1)x10(-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(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.
U2 - 10.1103/PhysRevLett.98.254504
DO - 10.1103/PhysRevLett.98.254504
M3 - Article
VL - 98
SP - 254504
JO - Physical Review Letters
JF - Physical Review Letters
SN - 0031-9007
IS - 25
ER -