Measurement of Townsend's Secondary Ionization Coefficient of MgO Film in Argon

Abstract

Townsend's secondary ionization coefficients γ of MgO in Ar are determined from the breakdown voltages and the Townsend's criterion. Breakdown voltages on MgO film are measured by the both wave forms, discharge current and applied voltage between the electrodes on the oscilloscope. According to the experimental procedure, γ of gold film and stainless steel electrodes are determined and compared with other experimental values. After the confirmation of the validity of those results, we have carried out the determination for γ of MgO. Furthermore, the influence of heating effect of MgO film to the value of γ is also discussed.