高能电子轰击金属靶产生正电子的模拟研究  

Simulation of positron production by high energy electron impacting metal target

作　　者：张登红[1] 袁肖肖 王伟[2] 于得洋[2] 蔡晓红[2] ZHANG Deng-hong;YUAN Xiao-xiao;WANG Wei;YU De-yang;CAI Xiao-hong(College of Physics and Electronic Engineering,Northwest Normal University,Lanzhou 730000,Gansu,China;Institute of Modern Physics,Chinese Academy of Sciences,Lanzhou 730000,Gansu,China)

机构地区：[1]西北师范大学物理与电子工程学院,甘肃兰州730070 [2]中国科学院近代物理研究所,甘肃兰州730000

出　　处：《西北师范大学学报（自然科学版）》2018年第6期47-51,共5页Journal of Northwest Normal University(Natural Science)

基　　金：国家自然科学基金资助项目(1167050517)

摘　　要：建立了高能电子束与固体作用产生正电子的蒙特卡罗模拟模型.得出了金属靶材料,靶厚度,电子束能量等对正电子产额的影响.模拟实验表明,金作为靶材料,正电子的产额最高.实验中1cm为最优靶厚度,在此厚度之外,正电子随着厚度增加而减少;对于电子束的能量而言,能量越高,正电子的产额越高,提高电子束能量是增加正电子产额的有效途径.此外,模拟实验还给出了以正电子为主的次级粒子的角分布及能谱,结果表明,次级粒子主要包括正电子,光子,及少量的中子和质子,而且,正电子发射具有明显前倾的特点,能量呈类麦克斯韦分布.In this paper,Monte Carlo Geant4 simulation models for the generation of positrons by high-energy electron beams impacting solid targets are established.The effects of metal target material,target thickness,and electron beam energy on the yield of positive electrons were obtained.Simulation experiments show that the gold target is the best target for positron yield.For the target thickness,1cm is the optimal thickness in the experiment.Outside this thickness,positrons decrease with increasing thickness.For the electron beam energy,the higher the energy,the higher the yield of positrons.Therefore,increasing the electron beam energy is an effective condition for increasing the positive electron yield.The angular distribution and energy spectrum of secondary particles dominated by positrons were given in simulation experiments.The results show that the secondary particles mainly include positrons,photons,and small amounts of neutrons and protons.Moreover,positron emission has a pronounced tendency to lean forward,with a Maxwell-like distribution of energy.

关 键 词：高能电子束 正电子 能谱 金属靶 

分 类 号：O572.322[理学—粒子物理与原子核物理]