Study on using the non-thin–non-thick target method to measure the atomic inner-shell ionization cross-sections induced by near-threshold energy electrons

Beijing Key Laboratory of Passive Safety Technology for Nuclear Energy, School of Nuclear Science and Engineering, North China Electric Power University - Beijing, China

Received: 12 January 2026
Accepted: 7 May 2026

Abstract

Near-threshold electrons may undergo a relatively high energy loss when colliding with target films that are several nanometers thick. In such cases, processing experimental data using the thin target formula method can lead to considerable inaccuracies in the resulting cross-section values. Targets within this energy loss range cannot be treated as either thin or thick targets, we regard them as non-thin–non-thick targets. In this study, we conducted experimental measurements of characteristic X-ray yields induced by near-threshold electrons on Al, W, and Bi targets using the scanning electron microscope facility at Sichuan University. Additionally, we applied numerical-neural network method developed by our research group to analyze the data and obtain K-shell ionization cross-sections of Al and characteristic X-ray production cross-sections of W and Bi for electrons below 30 keV. The obtained cross-section results were compared with those processed using the Monte Carlo (MC) neural network method, the thin target formula method, and theoretical predictions from the Distorted Wave Born Approximation (DWBA). The results indicate that processing experimental data for non-thin–non-thick targets using the thin target formula method is inaccurate, while neural network methods can more effectively handle such data, yielding reliable cross-section results.