The Theory and Properties of Low Voltage Radiation Counters

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Abstract
The behavior of permanent gas mixtures which lead to low breakdown potentials is discussed, and criteria are established for attaining minimum threshold and operating potentials for G‐M counters. Curves showing the dependence of counter characteristics upon pressure and electrode parameters have been obtained for various mixtures of neon and argon. The properties of cathode surfaces have been investigated and the criteria for obtaining suitable surfaces for counter operation were found. Two classes of counters were observed using these permanent gas mixtures. The first class possesses the lowest range of threshold potentials (approximately 115 to 135 volts) at pressures up to approximately 7 cm Hg. They require quenching circuits having relatively long time constants. The second class of counters have threshold potentials in the range of approximately 135 to 210 volts corresponding to pressures from 7 to 50 cm Hg. They operate with fast quenching circuits. Miniature portable radiation detectors and meters have been made using these detectors.