Recent Results on Radiative Electron Capture

Abstract

We have three new results concerning REC since our last publication.^1–3 (1) The measured REC cross-sections per K-vacancy scale according to the number of “free” electrons in the target atom at least for the cases of CI projectiles incident on C and Cu. “Free” electrons are those bound target electrons with average velocity ≪ than the projectile velocity. Excellent agreement with the Bethe-Salpeter free-electron theory⁴ is obtained if it is assumed that each “free” target electron contributes equally to the REC cross-section, and the effective Cl K-shell binding energy needed to compute the cross-section is taken as the measured thin target e.g. 10 µg/cm² REC centroid energy less the mean kinetic energy of the captured electrons in the projectile reference frame. Our methods of determining the experimental and theoretical REC cross-section per K-vacancy may explain some discrepancies found by Lindskog et al⁵.