The low-pressure mercury discharge under different modes of operation

摘要

It has been shown previously that the pulsed operation of a low-pressure discharge leads to modulated emission profiles, which one can follow through time [1], A single emission cycle of a low-pressure discharge in pulsed operation is characterised typically by a sequence of five periods of behaviour [2]. The first is a "dark" period between the application of the voltage and the onset of emission. The second is a rapid transient build up which leads into a third period of high current flow. The fourth period is the rapid decay of emission after the pulse is terminated and in the fifth and final phase an afterglow develops which continues until the next pulse rising edge. The duration of different phases depends sensitively on the applied field strength, pulse duration, repetition frequency, the buffer gas and its pressure, etc. In this study we have concentrated in the first three periods, which constitute the emissions during the application of the voltage pulse and looked into how the emission profiles recorded at various distances from the cathode differ.