权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Research development of microscopic track simulation codes for heavy ions

重离子微观径迹模拟程序研究进展

基本信息

批准号：
12680503
负责人：
UEHARA Shuzo
金额：
$ 1.6万
依托单位：
KYUSHU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12680503/
关键词：
Monte Carlo simulation Cross sections of interactions Charge exchanges Stopping power Heavy ion track structure Full slowing down code Microdosimetry Radiation action モンテカルロシミュレーションマイクロドシメトリ

项目摘要

1. IntroductionRadiation track structure (microscopic spatial distributions of ionization and excitation) obtained by Monte Carlo simulation contributes significantly to research of radiation effects. We have developed new generation track codes for low-energy protons and alpha particles, in which charge exchange processes and nuclear elastic scattering are taken into account.2.MethodsIn the energy range below 0.3MeVu^<-1> for H^+ and He^<++>, neutral or dressed ions such as H^0 or He^+ and He^0 are generated by electron capture. Experimental and theoretical cross sections for all these particles for water molecule were collected and compiled. Secondary electrons ejected by ion impact were traced by the electron code kurbuc developed by ourselves. The reliability of the codes was confirmed by comparing the various physical parameters with the published data3. ResultsCalculated electronic and nuclear stopping powers, ranges and W values agreed with ICRU data within 10% uncertainties. Th … More e codes provided various microdosimetric quantities such as radial dose distributions, restricted stopping powers and lineal energy spectra. These data were in good agreement with the published data.4. ConclusionsNewly developed low-energy codes, lephist for protons and leahist for alpha particles, are "full slowing down codes", not "track segment code" conventionally used. The impact on the research field of track structure may be large. The effective energy ranges are 1 keV to 1 MeV for protons and 1 keV to 8 MeV for alpha particles. Therefore, these are useful for applications to the mechanistic understanding of radiation effects of neutrons and heavy ions in environment. Track structure identifies the products of H_2O^+, H_2O^+ and e_<sub>^- at the physical stage. These products immediately form the radicals, OH, H, e_<aq>^-, and so on, due to chemical reactions with water molecules. The future objective is to develop an inclusive track structure code including radiation chemistry as a function of time between 10^<-15> and 10^<-6>s. Less

1.导论蒙特卡罗模拟得到的辐射径迹结构(电离和激发的微观空间分布)对辐射效应的研究具有重要意义。我们开发了新一代低能质子和α粒子的径迹程序，其中考虑了电荷交换过程和核弹性散射。2.方法在H^+和He^&lt；++&gt；的能量范围内，通过电子俘获产生中性离子或修饰离子，如H^0或He^+和He^0。收集和汇编了所有这些颗粒对水分子的实验和理论截面。用自行开发的电子代码kurbuc对离子碰撞产生的二次电子进行了追踪。通过将各种物理参数与已公布的数据进行比较，证实了程序的可靠性。结果计算的电子和核阻止能力、射程和W值与ICRU数据在10%的不确定度内一致。TH…更多的电子代码提供了各种微剂量学参数，如径向剂量分布、限制的阻止能力和线能谱。这些数据与已公布的数据吻合得很好。结论新开发的低能代码LEPHIST用于质子，LEHIST用于α粒子，是“完全减速代码”，而不是常规使用的“轨道段代码”。对轨道结构研究领域的影响可能较大。质子的有效能量范围是1keV到1 MeV，α粒子的有效能量范围是1keV到8 MeV。因此，这对于从机理上理解环境中中子和重离子的辐射效应是有用的。径迹结构确定了物理阶段H_2O^+、H_2O^+和e_<SUB>^-的产物。这些产物与水分子发生化学反应，立即形成自由基，OH，H，e&lt；aq&gt；^-等。未来的目标是制定一个包罗万象的轨道结构规范，包括辐射化学随时间的变化，时间介于10^&lt；-6；-6；S之间。