光子在组织等效介质中产生的次级电子能量分布研究  

Research on energy distribution of second electrons from photons impacting with atoms in tissue equivalent material

作　　者：张文仲[1] 郭勇[2] 

机构地区：[1]防化指挥工程学院,北京102205 [2]北京放射医学研究所,北京100850

出　　处：《核电子学与探测技术》2008年第3期620-626,共7页Nuclear Electronics & Detection Technology

摘　　要：本文探讨了不同能量光子在组织等效物质中产生的次级电子在能量上的分布规律。依据理论分析和计算，明确了水作为组织等效材料的合理性，利用MC方法中粒子输运技术，对光子在介质中行为进行了真实模拟。通过大量模拟计算，得到了不同能量光子与介质中原子（H、O）相互作用的事件类型的比例分布情况以及在这些事件中产生的次级电子能量分布的真实情形。光子能量小于28keV时，光子与介质原子之间的作用以光电效应为主；能量为28-30keV的光子，光电效应与康普顿散射几率大致相等；能量大于30keV的光子，康普顿散射事件逐步占据主导地位，这种事件几率随光子能量的增加而增大。For research the energy distribution rules of second electrons from photons with different energy which impact with atoms in tissue equivalent material, based on theory analysis and some calculation, are drawed a conclusion that water is a sort of reasonable tissue equivalent material The photon traces in the material were simulated by particle transport technique using Monte Carlo method. A large number photons were transported, the ratio of photoelectric effect to Compton effect was acquired in the tissue equivalent material, meanwhile the energy distribution states of second electrons were observed when photons impact with atoms（H、O） in the material. When the energy of photon is below 28keV, the probability of photoelectric effect will be sign/ficant; As the energy of photon is between 28keV-30keV, both photoelectric effect and Compton effect will happen in the same probability; The Compton effect will be mainly form in the material when the energy of photon is above 30keV.

关 键 词：光子 组织等效物质 次级电子 能谱 

分 类 号：O572[理学—粒子物理与原子核物理]