Production of projectile and targetK X-rays by single and multiple electron-capture in collisions of Si14+ and Si13+ ions with argon atoms at 4.5 and 5.5 MeV/amu

Abstract

Projectile and target X-ray cross-sections have been measured in collisions of bare and hydrogenlike Silicon ions with argon atoms. Projectile energies are 125MeV and 153 MeV, i.e. the intermediate velocity region for K-shell capture. Coincidence measurements between X-ray photons and the scattered Si "+ projectiles with charge states n-1, n-2 and n-3 have been made. The relative contribution of charge exchange and direct ionization (or excitation) of the target K-shell has been obtained directly by this new method. Double K-shell electron transfer is demonstrated to be very large in the case of fully stripped Si ions. A thorough theoretical analysis of the data is carried out and multiple capture processes are evaluated using an independent electron model.

Dissociation of multicharged CO molecular ions produced in collisions with 97-MeVAr14+: Dissociation fractions and branching ratios

“…Similar charge multiplication effects caused by Auger decay of L vacancies have been observed in collisons of 1-MeV/amu 0 and F ions with Ar [12]. The dominant mechanism for K-vacancy production in the Ar' ++CO collision system is electron capture to the Ar L shell [13]. However, this same mechanism must also contribute to the Ne results.…”

Multiple electron capture in close ion-atom collisions

“…The only previous report of the cross section for multiple-electron capture being larger than that for single-electron capture, determined by ion-x-ray coincidence, is the observation of double K-to-K transfer in collisions of bare 4.5-MeV /u Si ions in Ar. 12 The results of reference 11 were recently extended to measure capture of up to eight electrons, and the projectile velocity has been varied.l3 New results are presented here for varying the projectile charge state, which varies the number of initial vacancies in the projectile L shell.…”

Electron capture from the krypton M-shell by MeV protons

“…Recently, Belkic et al [10] extended the method of obtaining the CDW electron capture cross section for transitions between arbitrary subshells of an atom. Subsequently, this extended CDW approximation has been used by Andriamonje et al [11] in a detailed evaluation of the cross section for electron capture from the L-shell to L and M-shells in Siq+-Ar collision, with the charge state q = 13 and 14.…”