It is proposed to measure absolute doubly differential cross sections for secondary electrons ejected from atomic hydrogen by electron impact (threshold 2 KeV). A modulated crossed-beammethod will be used, and the atomic hydrogen beam will be provided by a microwave discharge technique. The energy and angular range of the measured secondary electrons will be from 1.0 eV to near the incident energy and from 6 to 160 degrees, respectively. A particular emphasis will be on the measurements in the low energy range for both incident and secondary electrons. This research program will enable a crucial test of the collision theory and three body continuum problem because the wave functions of atomic hydrogen are known.
