Doubly differential cross sections for electron-impact ionization of propane in the energy range from 30 eV to 1 keV

Abstract

Doubly differential electron-impact ionization cross sections of propane were comprehensively measured for electron energies between 30 eV and 1 keV as a function of secondary electron energies and emission angles. The measurements were carried out for secondary electron energies from 3 eV to about half of the primary energy and for emission angles between 10° and 135°. To facilitate practical application and implementation of the data into numerical codes used for radiation transport calculations, a semi-empirical formula was constructed on the basis of existing models. The semi-empirical formula is capable of reproducing the measured data well over a wide energy and angular range. Singly differential ionization cross sections were obtained by the integration of the experimental data over the emission angles and total ionization cross sections (TICSs) were determined by the integration of the data both over the emission angles and secondary electron energies. They were compared to the theoretical results calculated using the binary-encounter-Bethe (BEB) model. The calculated TICSs mostly agree with the data published by other groups within the experimental uncertainties.