Electron Energy Conversion to EUV Radiation in the K_α Line of Be in the "Shooting Through" Geometry

A model is presented and the interaction of accelerated electrons with atoms in a thin film "shooting through" Be target is theoretically described. The algorithm is based on the Monte Carlo simulation of the electron motion in the target accompanied by energy losses in elastic and inelastic interactions. The conversion of the electron energy to the radiation energy in the 11.4-nm K_α line of Be and the emission spectrum are calculated. The maximum conversion efficiency to the solid angle 4π CE = 3.0 × 10^–4 is achieved for the electron energy E_e = 2.0 keV and a 40-nm-thick freely suspended beryllium film. 200-nm and 400-nm-thick films were experimentally investigated. The maximum conversion efficiency to the solid angle 4π for a 200‑nm-thick film and the electron energy E_e = 2.75 keV was CE_exp = 9.2 × 10^–5, whereas the calculated value was CE_calc = 2.5 × 10^–4. The observed discrepancy between the theory and experiment is explained in the paper.