Doubly differential cross sections of secondary electrons ejected from atomic hydrogen by electron impact

We have measured the doubly differential cross sections, in angle and energy, of secondary electrons ejected from atomic hydrogen by electron impact. The incident energies used were from 25 to 250 eV. The energy and angular range of secondary electrons measured were from 1.0 eV to one-half of the difference between the incident energy and the ionization potential of hydrogen atom and from 12 degree to 156 degree, respectively. Singly differential cross sections and total-ionization cross sections were obtained from the doubly differential cross sections. The present total-ionization cross sections were compared with previous measurements and theoretical results. Discrepancies have been found between the present results and those measurements and theoretical results