Measurements of Absolute Electron Capture Cross Sections in He2+ -He and Ne8+ -O2, N2, CH4 Collisions

Abstract: The total absolute cross sections of single- and double-electron capture (SEC and DEC) in the collisions of He²⁺ with He and Ne⁸⁺ with O₂, N₂, and CH₄ were studied in the energy ranges 3.5 to 50 keV/u and 2.8 to 40 keV/u, respectively. Through a deep analysis of the experimental systematic uncertainties in the measurement procedure and data evaluation, the error in the experimental results of the SEC cross sections is less than 9%. Within the uncertainties, the present results of the He²⁺ -He collision show good consistency with previous measurements, validating the experimental system and paving the way for precise measurements of EC cross sections for a variety of ions and neutral gases. The present measurements allow for a test of EC theory and provide crucial EC cross section data for the establishment of plasma models in fusion research and astrophysical X-ray studies.