Chapter VI the breakdown of dielectrics

Based on a preliminary notice a review of work on electron avalanches and avalanche growth in gases by Raether¹ was mentioned in the 1960 digest. The publication year has since been changed to 1961 and it is, therefore, also included in the bibliography this year. Several other papers on electron avalanche growth and their statistics appeared. Dibbern² used photomultiplier techniques to study the electron components of single electron avalanches in methane and nitrogen and their mixtures and gave drift velocities for electrons in some nitrogen-methane mixtures. Legler³ treated the statistics of electron avalanches in electronegative gases theoretically by assuming high fields and large gas amplification. The results were found to agree well with experiments. Electron detachment from negative ions was studied experimentally by Schlumbohm⁴ who also found good agreement with theory. Kluckow⁵ treated current growth in a Townsend-discharge theoretically for three different cases by assuming: 1) discharge initiated by a single electron, 2) discharge initiated by a great number of electrons released during the build-up time and 3) discharge initiated by almost simultaneous release of 10³ to 10⁶ electrons from the cathode. The latter case could be realized by shining a short flash of ultraviolet illumination on the cathode and in a second paper Kluckow⁶ treated this case for hydrogen gas. Positive ion currents and conditions for breakdown were also evaluated in this paper.