The properties of current limited spark chambers

Abstract

An investigation has been made of the characteristics of the current limited spark chamber, in which it was found that certain anomalies existed in its operation. Such discrepancies are not found in the operation of the more conventional types of chamber. They are thought to be due to charge deposited on the dielectric walls producing internal electric fields across the gas which reduce the chamber efficiency. The variation of the clearing field has been investigated in regions far from the discharge, and would appear to be present throughout the chamber. Measurement of the decay constant of the charge agreed well with the value calculated considering the chamber capacity and surface resistivity of the glass, although on application of this constant, to determine equilibrium values of the clearing fields, a second, much longer decay process seemed to be suggested. A theoretical model for handling such small clearing fields has been examined, and applied to the system, thus giving an indication of the electron drift velocity and density of charge deposited on the walls The development of an approximate semiquantitative model of spark breakdown shows how different pulse delays will affect the growth of streamers, and describes qualitatively certain characteristics of the discharges noted during chamber operation. However, the lack of more detailed knowledge of certain discharge parameters does not allow a more detailed comparison.