Die Statistik der Elektronenlawinen in elektronegativen Gasen, bei hohen Feldstärken und bei großer Gasverstärkung

Abstract

The statistical distribution of the carrier number of single electron avalanches in a TOWNSEND discharge is described by v(n) = 1/n·exp (—n/n̄) if one introduces some simplifying assumptions. These assumptions are violated in the case of electronegative gases, in strong electric fields, and in the case of large gas-amplification. In electronegative gases only a part of the primary electrons form observable electron avalanches. These are still subject to an exponential distribution but with an increased mean value. In strong electric fields the ionization probability depends on the previous history of the individual electrons. This leads to a distribution with a marked maximum and a reduced dispersion. In a first approximation the form of the distribution is determined by the quotient E/α: U_i. In the case of large gas-amplification the further development of the avalanche is influenced by the space charge and one gets a modified exponential distribution. The calculated distributions agree well with the experiments of other authors.