The Refractive Indices and Dielectric Constants of Air and its Principal Constituents at 24,000 Mc/s

Abstract

The refractive indices of air and its principal constituents have been measured at a frequency of 24,000 Mc/s. with a precision comparable with that obtained in the optical range. The method is based on the measurement of the resonant frequency of a cavity resonator first when it is filled with the gas and then when it is evacuated. The source of oscillations used is a Pound-stabilized velocity-modulated oscillator, and its frequency is measured by reference to a high harmonic of a quartz standard, with a precision of 1 part in 108. The cavity is provided with a tuning plunger, which changes the resonant frequency through a range of about 10 Mc/s, and is calibrated to an accuracy of within 1 kc/s.