ELECTRON-IMPACT EXCITATION OF THE 3(3)P STATE OF HELIUM - COHERENCE PARAMETERS

In an electron-photon coincidence experiment the authors have measured the polarization degree of the decay radiation from the electron impact excited 33P to 23S transition in helium. They performed their measurements perpendicular to the scattering plane. To analyse the polarization they used a beam splitting polarizer instead of the usual sheet polarizer. The linear polarization degree was measured at an electron impact energy of 40 eV and the circular polarization degree was measured at 40, 60 and 80 eV. The electron scattering angle ranged from 32.8’ to 116’. The experimentally determined degrees of polarization are in good agreement with the theoretical results of the distorted-wave Born approximation (DWBA). The scaling relation of Lin et al. (1989) is in agreement with the DWBA results of the circular polarization for 33P excitation. © 1990, IOP Publishing Ltd.