DETERMINATION OF TOTAL EXCITATION CROSS SECTION IN NEON BY COMPARISON OF THEORETICAL AND EXPERIMENTAL VALUES OF TOWNSENDS PRIMARY IONIZATION COEFFICIENT

It is shown that previous theories relating transport and ionization coefficients to fundamental collisional processes between electrons and atoms are incomplete, and can, in some cases, lead to considerable error. The influence of diffusion and injection of new electrons into the discharge through ionization are taken fully into account in the development of a more rigorous Boltzmann equation, which is then solved numerically. A total excitation cross section is found which gives good agreement between experimental values of Townsend's primary ionization coefficient and theoretically predicted values over almost the whole range of E/p0 where experiments have been carried out. The cross section covers a range of electron energy up to 50 eV, and is about 20% lower than the experimental cross section of Maier-Leibnitz.