Measurement of Electric Fields as Applied to Glow Discharges

Abstract

Using a combination of well‐known techniques, it has been possible to develop a magnetically compensating, ultra fine, high sensitivity, zero deflection electron beam probe method with automatic recording for measuring fields in glow discharges applicable to a wide variety of similar problems. Fields ranging from 1000 down to 0.2 volts per cm have been measured in one‐twentieth or less the times required with previous techniques and with a gain in sensitivity by a factor of ten or better. Wall potentials can simultaneously be recorded. The method is limited to pressures below about 3 mm for 10 cm diameter glows by diffusion of the beam, but correspondingly greater pressures can be used in smaller tubes or with higher energy (say 50 kv) electron beams. The limitations imposed by the effect of the disturbing magnetic field on the discharge are indicated and examples are given of data taken in a glow discharge.