Coincidence studies of He (11S-21P) excitation by electron impact

Abstract
Three different approaches, using coincidence techniques, are described and results presented relative to the excitation of the substrates of He (21P) by electrons of incident energy between 30 and 80 eV and for electron scattering angles from 5 degrees to 42 degrees . One approach involved a vacuum UV polarization analysis. The results show a wide divergence between experiment and the existing theories at the larger scattering angles.