Processes in gases at low pressures induced by electrical breakdown and their influence on the memory effect

This review article first analyzes general characteristics of the electrical breakdown at low pressures, definition of breakdown voltage, and methods for its determination. Characteristic gas-filled diode is the delay of electrical breakdown even when the connected voltage is significantly higher than the breakdown voltage and that time is called the electrical breakdown time delay. Special attention is focused on the dependence of the mean value of electrical breakdown time delay as a function of time between two voltage pulses (relaxation time or afterglow period). This dependence is known as the memory curve. The analysis of these dependences enable the possibility to monitor the presence of certain types of particles in the gases whose energy is sufficient to release electrons upon hitting the cathode, which will initiate the next breakdown. Those particles are responsible for the appearance of memory effect. The presence of these particles has been traced to such low concentrations when cosmic radiation and natural environmental radiation play a dominant role in initiating the breakdown. Since this review article discusses the memory effect in nitrogen and noble gases, significant attention is devoted to the processes in these gases that occur during electrical breakdown, self-sustaining discharge, and during relaxation time and their influence on the behavior of memory curves.