Doubly differential cross section of secondary electrons ejected from gases by electron impact: 50-400 eV on CO2

Doubly differential cross sections of secondary electrons ejected from C${\mathrm{O}}_2$ by electron impact have been measured by means of a crossed-beam method. The incident energies used were 50, 100, 200, and 400 eV. The energy range and angular range of secondary electrons measured were from one-half of the difference between incident energy and ionization potential to 1.0 eV and from 12 to 156°, respectively. The present results agree with the results of Rapp and Englander-Golden for the total ionization cross sections and with that of Opal et al. for the singly differential cross sections. The doubly differential cross sections show larger values at extreme angles and smaller values near 90° than those of Opal et al.