K-shell ionization and characteristic x-ray radiation by high-energy electrons and positrons in oriented silicon crystals

Abstract

K-shell ionization and characteristic x-ray radiation (CXR) by high-energy electrons and positrons in oriented silicon crystals are studied using computer simulation. A method for this simulation has been developed and is described in detail. The evolution of the angular distribution of CXR from the upstream surface of the crystal with changes in the angle between the incident particle momentum and the crystal <100> axis or (100) plane, as well as with changes in particle energy over a wide range (1-1000 GeV), is investigated. It is shown that in most cases this evolution is non-monotonic. The physical mechanisms underlying this behavior are discussed. In particular, the impact of the dechanneling process on CXR produced by electrons is analyzed.