R-MATRIX CALCULATIONS FOR DOUBLE-DIFFERENTIAL CROSS-SECTIONS IN ELECTRON-IMPACT IONIZATION OF HELIUM

Double-differential cross sections for electron-impact ionization of h elium are calculated within the R-matrix method. Angular dependences o f the cross sections are presented for the primary (scattered) and sec ondary (ejected) electron for the case where the energy of the primary electron is large compared to that of the secondary electron at incid ent energies of 100, 200 and 300 eV. Comparison with experiment and ot her theories is made and the results are discussed based on the charac teristics of the angle-integrated triple-differential cross section.