Glow Discharge Detection of Long Wavelength Electromagnetic Radiation: Cascade Ionization Process Internal Signal Gain and Temporal and Spectral Response Properties

Abstract

The mechanism of long wave electromagnetic signal detection by glow-discharge plasma, based upon gas breakdown theory by high frequency electric fields, is developed to include internal signal amplification of the order of that associated with the photomultiplier, upper and lower limits to response linearity, temporal and spectral response properties, and noise in the abnormal glow discharge. Agreement between signal-to-noise expressions in this analysis and measurements involving simple and inexpensive glow discharge indicator lamps exhibiting excellent sensitivity to microwave radiaion is quite good. An inherent ideal limit to speed of response is derived which indicates picosecond-order risetimes are theoretically possible if parasitic reactance effects which limit risetimes of present day devices to microsecond order can be overcome. Sensitivity can be improved further by increasing the number of free electrons. Enhanced diffusion current losses for a subnormal glow yield spectrally flat response which can be useful in radiometric applications.