Doubly differential cross sections of secondary electrons ejected from molecular oxygen by electron impact

A measurement of the doubly differential cross sections of secondary electrons ejected from molecular oxygen by electron impact has been made. A modulated crossed-beam method was used with incident electron energies from 25 to 250 eV. The energy and angular range of secondary electrons covered from 1.0 eV to one-half of the difference between the incident energy and ionization potential and from 12 degree to 156 degree, respectively. The present results have been compared with the previous measurements and considerable discrepancies were found