Spectral-noise characteristics of glow discharges in the frequency range 1kc/s¿8Mc/s

Measurements of the small-signal impedance and noise voltage have been made over the frequency range 1 kc/s to 8 Mc/s for glow-discharge tubes filled with pure neon at pressures from 10 to 60torr. The equivalent circuits of the discharge with respect to the impedance and noise are shown, and the spectral variations of noise voltage and current are explained with reference to them. The relationship between the noise-current spectrum and the convection-current admittance is also given. It has been found that the high-frequency white-noise current from the gas tube is not the same as the shot noise in a temperature-limited diode carrying the same tube current.