Chapter X: The breakdown of dielectrics

As in previous years there has been much activity in the field of electrical breakdown during 1964. In the section dealing with gas breakdown, work pertaining to phenomena outside the normal range of gas discharges has not been included. Thus, high energy ionization processes and plasma physics are not included, although in some cases the discharges required to form the plasma are of interest. Several important books relating to gas breakdown have been published. Physics of Atomic Collisions by Hasted contains a good account of atomic collisions and other phenomena associated with the study of ionized gases. The appearance of Raether's book Electron Avalanches and Breakdown in Gases will be welcome to all who are working directly in this field or are only interested in a general way. In this volume is contained a summary of the theoretical and experimental work on single electron avalanches as well as the processes leading to a succession of avalanches, and ultimately to breakdown. Much of this material has not been published in English before. The various techniques for observing the development of avalanches are considered in detail; and the results obtained for diffusion coefficients, carrier statistics, electron and ion drift velocities, ionization, and attachment coefficients from these measurements are given. Space charge effects in avalanches of high carrier density are of particular interest. The generation of successions of avalanches resulting from photon and ionic secondary mechanisms is then considered, and the development of a discharge through either the Townsend or streamer mechanism is discussed in detail. A chapter is devoted to applications such as spark chambers and counters; and finally in an appendix, the theories of the transient current build-up are described.