Determination of electric field-dependent effective secondary emission coefficients for He/Xe ions on brass

摘要

Effective secondary emission coefficients, γ_(eff), for He~(+) and Xe~(+) ions are determined from the experimental Paschen curves of Postel and Cappelli Appl. Phys. Lett. 76, 544 (2000) through Townsend's condition for a self-sustained discharge. The γ_(eff) dependence on the reduced electric field E/p, where p is the gas pressure, is obtained using the calculated dependence of the reduced Townsend's ionization coefficient α(E/p)/p on the reduced electric field. Average values of the secondary emission coefficients are also estimated for brass and atomic and molecular ions as well as excited atoms and molecules of He and Xe, through a best fit of the simulated Paschen curves to the experimental ones. The found average values of the secondary emission coefficients are 0.1 for He and 0.0016 for Xe. Comparison is made with the limited available experimental results.