Abstract
The angular distribution of electrons elastically scattered from He has been measured by electron impact utilizing a crossed-beam method. The energy and angular range measured were from 2.0 to 400 eV and from -96° to + 156°, respectively. The present results have been normalized to LaBahn and Callaway's theoretical value at 10.0 eV. The present results agree, in general, with a few previous measurements; however, there are still discrepancies in a detailed shape and magnitude among the measurements. The various theories need more improvements, especially for the backward scattering. It is found that the Born approximation is not yet adequate at 400-eV incident energy.