Pulse Height Spectral Analysis of an Ozonizer Discharge and the Associated Joshi Effect†

Abstract

Measurements by a single channel pulse height analyser of the amplitudes of the discharge pulses in H2, He, Cl2 and I2 vapour excited by a. c. potentials in ozonizers of the Siemens type show a continuous pulse amplitude spectrum from above the noise level (∼0·3 v) to a maximum amplitude whose value depends on the excitation potential. At a given value of the latter, the number of pulses diminishes rapidly with increasing amplitude both in the low (l-25 v) and high (55-99 v) amplitude regions, with a plateau of low slope in between. A side by side measurement of the Joshi effect (i.e. change ± Δi in the discharge current due to external light) revealed a definite dependence of the sign and magnitude of the Ai on the pulse amplitude in all the systems studied. Thus, on irradiation of the discharge by light from a 100 w lamp, the shorter ( <25 v) amplitude pulses showed a 100% increase in number while those of larger amplitudes diminished by 40 to 70 % and pulses of amplitudes above 30 v were completely sup...