Electron Temperature, and Noise Temperature at 3,000 Megacycles, of Discharges in Argon

Abstract

Noise temperatures at 3,000Mc were compared with the corresponding electron temperatures for the positive columns of some cold cathode discharges in argon. The noise temperatures were measured, using a superheterodyne receiver of low noise figure, by comparing the noise outputs of the various tubes with that from a commercial six watt fluorescent lamp of measured noise output, a rapid comparison between known and unknown noise powers being effected by means of a hand-operated waveguide switch. The noise temperature of the fluorescent lamp in its mounting was measured by comparison with an absolute standard consisting of an incandescent tungsten filament lamp fitted in a suitable waveguide holder. Electron temperatures were measured by the Langmuir single probe method. It is concluded that for most of the tubes measured, noise temperature and electron temperature are in close agreement as required by the theories. The theoretical basis of the work is discussed and gaseous discharge positive column noise is related to the development of noise theory is general. Three theoretical methods for showing the equality of noise and electron temperatures are presented and discusses, and the relationships between them considered.