Absolute differential cross sections for elastic scattering of electrons by helium, neon, argon and molecular nitrogen

Abstract

An electron spectrometer has been constructed for the study of elastic and inelastic electron scattering processes. Up to now the apparatus has been used to measure differential cross sections of electrons elastically scattered by He, Ne, Ar and N2. Direct absolute cross section measurements were performed on N2 at 500 eV impact energy and at scattering angles between 5 degrees and 9 degrees . Relative cross section measurements were done on He, Ne, Ar and N2 at impact energies between 100 and 3000 eV and scattering angles between 5 degrees and 55 degrees . The relative cross sections were put on an absolute scale by means of the apparatus calibration factor derived from the absolute measurements on N2. Analysis of the exponential behaviour of the differential cross section as a function of momentum transfer yielded apparent polarizabilities of the target.