MEASUREMENT OF THE ENERGY-DISTRIBUTION OF LOW-ENERGY ELECTRONS AS A FUNCTION OF GAS-DENSITY - DETERMINATION OF ABSOLUTE DIFFERENTIAL ELECTRON-ATOM SCATTERING CROSS-SECTIONS

The development of a sophisticated radiation detector and the study of its energy and directional response require accurate excitation and ionisation cross sections for electrons as a function of energy and angle. However, there is a serious lack of accurate scattering cross sections for electrons of energies of less than a few keV, which usually make up the main body of secondary electrons. A procedure is described with which absolute differential cross sections for electron collision processes tan be measured at low scattering angles. With this procedure, absolute differential cross sections for the 1(1)S --> 2(1)P transition in He are measured for electron energies from 0.6 to 2.0 keV at scattering angles of less than 1.0 degrees. Furthermore, the differential cross sections for the 2P --> 3S transition in Ne are determined for energies from 1.0 to 2.0 keV in the small angle range.