Sigmund P, Schinner A
Physics Department, Odense University (SDU), DK-5230 Odense M, Denmark.
Phys Rev Lett. 2001 Feb 19;86(8):1486-9. doi: 10.1103/PhysRevLett.86.1486.
The long-standing problem of the lacking signature of a Barkas effect in the stopping of swift heavy ions under channeling conditions has been analyzed theoretically. The stopping model provides explicit dependences on impact parameter and allows for projectile screening and higher-order Z(1) corrections. The analysis differentiates between principal target shells. A distinct Barkas correction is found in accordance with standard theory. It is less pronounced for channeled than for random stopping because of the dominance of outer target shells. Varying contributions from different target shells to the stopping force may give rise to an inversion of the commonly observed variation with ion energy and charge state of the Barkas correction.
从理论上分析了在沟道条件下快速重离子阻止过程中缺乏巴尔卡斯效应特征这一长期存在的问题。该阻止模型明确给出了对碰撞参数的依赖关系，并考虑了射弹屏蔽和高阶Z(1)修正。分析区分了主要的靶壳层。根据标准理论发现了明显的巴尔卡斯修正。由于外层靶壳层占主导，对于沟道中的情况，该修正不如随机阻止时那么明显。不同靶壳层对阻止力的贡献变化可能导致巴尔卡斯修正随离子能量和电荷态的常见变化出现反转。
