Hamm R N, Turner J E, Ritchie R H, Wright H A
Radiat Res Suppl. 1985;8:S20-6.
Detailed Monte Carlo calculations are presented of proton and alpha-particle tracks in liquid water. The computations treat the interactions of the primary particle and all secondary electrons on a statistical, event-by-event basis to simulate the initial physical changes that accompany the passage of an ion through water. Our methods for obtaining the cross sections needed for such calculations are described. Inelastic scattering probabilities (inverse mean free paths) are derived from a complex dielectric response function constructed for liquid water, based on experimental and theoretical data. Examples of partial cross sections for ionization and excitation by protons are shown. The computation of electron transport and energy loss includes exchange, elastic scattering, and a scheme for the delocalization of energy shared collectively by a large number of electrons in the condensed medium. Several examples of calculated proton and alpha-particle tracks are presented and discussed. The meaning and significance of the concept of a track core are briefly addressed in the light of this work. The present paper treats only the initial, physical changes produced by radiation in water (in approximately 10(-15) s in local regions of a track). The work described here is used in calculations that we have reported in other publications on the later chemical development of charged-particle tracks.
本文给出了质子和α粒子在液态水中径迹的详细蒙特卡罗计算结果。这些计算在统计的、逐个事件的基础上处理初级粒子和所有次级电子的相互作用，以模拟离子穿过水时伴随的初始物理变化。描述了我们获取此类计算所需截面的方法。非弹性散射概率（平均自由程的倒数）是根据基于实验和理论数据构建的液态水复介电响应函数推导出来的。给出了质子电离和激发的部分截面示例。电子输运和能量损失的计算包括交换、弹性散射，以及一种用于处理凝聚介质中大量电子集体共享能量的离域化方案。给出并讨论了几个计算得到的质子和α粒子径迹示例。根据这项工作简要讨论了径迹核心概念的含义和意义。本文仅处理辐射在水中产生的初始物理变化（在径迹的局部区域约10^(-15)秒内）。我们在其他关于带电粒子径迹后期化学发展的出版物中所报道的计算中使用了这里描述的工作。
