FIRST TOWNSEND IONIZATION COEFFICIENT IN HYDROGEN.
LOCKHEED MISSILES AND SPACE CO PALO ALTO CALIF LOCKHEED PALO ALTO RESEARCH LAB
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Roses measurements of the first Townsend ionization coefficient N in hydrogen for Ep100 V 1cm Torr have been questioned by a number of authors principally either because of a supposed neglect of the second Townsend ionization coefficient G, or because electrons allegedly do not have an energy distribution which is only characteristic of Ep, or because of gas purity. In order to resolve these questions, new measurements of N in hydrogen have been carried out for 50or Ep or 800 in an ultrahigh-vacuum system. The present work takes G into account, and the values of N obtained are in agreement with those of Rose over the whole range of Ep studied. Various methods of evaluating N from prebreakdown ionization currents are critically discussed. The present results show that prebreakdown ionization-current data in hydrogen can be represented in the usual way, at least up to Ep 800. Author