Compton scattering energy spectrum for Si and Ge systems

In the present work, we study the atomic Compton scattering that could have a great impact on dark matter direct detection experiments. We give a quantitative analysis of the Compton scattering energy spectrum for Si and Ge atomic systems. The theoretical results on Compton scattering are calculated within the frameworks of free electron approximation (FEA) and relativistic impulse approximation (RIA). The low-energy transfer and near photoionization threshold regions are especially considered in this work. In RIA calculations, to obtain the atomic ground states, we adopt an ab initio calculation in the fully relativistic Dirac–Fock theory.