Electron impact excitation of the 31P state of helium using the electron-photon angular correlation technique

Excitation of the 3 1 P state of helium by low-energy electrons has been studied by measurement of the angular correlations between the scattered electrons and the 501.6 nm photons emitted in decay to the 2 1 S state. Measurements have been made over a large angular range at incident electron energies of 26.5 and 29.6 eV. Comparisons are made with a very recent 19-state R-matrix calculation and with 2 1 P data previously reported, McAdams et al. (1980), Crowe and Nogueria (1982).