Electron scattering from argon: Data evaluation and consistency

Abstract

The demand for coherent scattering data for modeling electron transport in matter has increased in recent years. While much effort has been devoted to the improvement of models describing electron transport and scattering, the updating of fundamental data sets on the basis of recent experimental results has often been neglected. The use of a well-validated set of electron cross sections ensures accurate calculations of transport parameters and ionization yields, with typical applications in material analysis, detector response studies, plasma diagnostics, physics of the atmosphere, and radiotherapy. Data consistency can be verified on the basis of various theoretical requirements, and systematic errors can be minimized by cross-checking results obtained from independent experiments. For example, the oscillator strength distribution of an atom can be obtained both from photoabsorption experiments and from zero-angle electron-atom collisions at high energy, on the basis of the Bethe theory. A considerable number of all electron-scattering experiments are concerned with light noble gases, in particular with argon. This gas is a dominant constituent of noble-gas discharge plasmas and plays an important role in rare-gas halide lasers and proportional scintillator counters. This work reviews electron-scattering cross sections and optical data for the argon atom, discusses the progress made in the field of electron scattering and photoabsorption, and focuses on the most appropriate criteria for verifying data consistency.