Systematics of heavy-ion charge-exchange straggling

NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS

卷:384

Article

Sigmund, P.¹  Schinner, A.² 

[1] Univ Southern Denmark, Dept Phys Chem & Pharm, DK-5230 Odense M, Denmark

[2] Johannes Kepler Univ Linz, Dept Expt Phys, A-4040 Linz, Austria

关键词: Stopping power;    Straggling;    Swift heavy ions;    Charge states;    Shell effects;   

DOI  :  10.1016/j.nimb.2016.07.016

来源: Elsevier

【 摘 要 】

The dependence of heavy-ion charge-exchange straggling on the beam energy has been studied theoretically for several ion-target combinations. Our previous work addressed ions up to krypton, while the present study focuses on heavier ions, especially uranium. Particular attention has been paid to a multiple-peak structure which has been predicted theoretically in our previous work. For high-Z(1) and high-Z(2) systems, exemplified by U in Au, we identify three maxima in the energy dependence of charge-exchange straggling, while the overall magnitude is comparable with that of collisional straggling. Conversely, for U in C, charge-exchange straggling dominates, but only two peaks lie in the energy range where we presently are able to produce credible predictions. For U-Al we find good agreement with experiment in the energy range around the high-energy maximum. The position of the high-energy peak which is related to processes in the projectile K shell is found to scale as 4, in contrast to the semi-empirical 412 dependence proposed by Yang et al. Measurements for heavy ions in heavy targets are suggested in order to reconcile a major discrepancy between the present calculations and the frequently-used formula by Yang et al. (C) 2016 Elsevier B.V. All rights reserved.

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