Experimental Determination of the Electron-avalanche and the Electron-ion Recombination Coefficient

The electron-ion recombination coefficient 7 and the avalanche coefficient S = (or -a) ud, where (L and a are the ionization and attachment coefficients respectively and Vd the drift velocity of the electrons, have been experimentally determined in a self-sustained COz-laser system (1: 1:3 mixture) as a function of the E/N value. For low voltages we found the expected decrease of the recombination coefficient for increasing E/N values. However, it appears that for larger voltage the recombination coefficient increases sharply for increasing E/N values. The measurements of 6 show a much smaller value than expected from theoretical calculations. This must be explained by a lower value of the electronenergy distribution function for higher energies, which may be consistent with our measured high recombination probability for electrons having high energy.