Time delay of recombination luminescence: Electron thermalization in xenon gas and xenon-nitrogen gas mixtures excited byCf252fission fragments

A time delay of recombination luminescence has been observed in xenon gas and xenon-nitrogen gas mixtures excited by ${}_{}{}^{252}{}_{}{}^{}\mathrm{Cf}$ fission fragments. The measured delay times are in good agreement with the calculated electron thermalization time in the gases. The effect of nitrogen in xenon on the thermalization process is found to be appreciable for [${\mathrm{N}}_2$]/[Xe] > ${10}^{-3\mathrm{}}$, as a result of inelastic collisions by a rotational energy-transfer process for the electron energy of less than 1 eV.