Calculation of the efficiency of the utilization of alpha particles to preionize the working mixture in gas-discharge lasers and amplifiers

The spatial distribution of the rate of ionization of laser mixtures by alpha particles from a radioactive-isotope layer is analyzed theoretically. Conditions under which the uniformity of ionization by alpha particles is not less than that of ionization by electrons are established, and the possibility of passing to an electroionization excitation mode (where the conductivity of the discharge plasma is sustrained solely through an external ionization source) is evaluated. Results are presented for a CO2:N2:He = 1:5:4 mixture. It is shown that an equivalent current density of 0.1 micro-A/sq cm amagat is sufficient for the efficient preionization of the working mixtures in electric-discharge lasers and amplifiers, but that the corresponding ionization rate is too small for electroionization excitation.