北京大学静电加速器及其应用  

Electrostatic accelerator facilities and their applications at Peking University

作　　者：徐川[1] 付恩刚 高原[1] 任晓堂[1] Chuan Xu;Engang Fu;Yuan Gao;Xiaotang Ren(State Key Laboratory of Nuclear Physics and Technology,School of Physics,Peking University,Beijing 100871,China)

机构地区：[1]北京大学物理学院核物理与核技术国家重点实验室,北京100871

出　　处：《科学通报》2023年第9期1096-1103,共8页Chinese Science Bulletin

基　　金：国家自然科学基金(U21B2082)资助。

摘　　要：加速器在核物理、材料科学、考古等领域都有着广泛应用.北京大学在20世纪90年代左右有3台静电加速器投入运行,分别是1.7 MV串列静电加速器、4.5 MV单级静电加速器和6 MV串列静电加速器.1.7 MV串列静电加速器配备有高频电荷交换负离子源和铯溅射负离子源,可引出从H到Au之间大部分元素的离子,离子能量从几百keV到若干MeV,主要开展室温及高温离子辐照实验、背散射和沟道分析等离子束分析工作.近年,利用离子辐照束线在核材料研究等方面取得了许多重要科研成果.4.5 MV静电加速器端电压在0.7~3.8 MV连续可调,主要加速氢/氦同位素离子,并可通过辐照靶材料产生准单能直流/脉冲中子场.该中子场主要应用于(n,α)核反应截面的测量.近年,基于4.5 MV静电加速器建立了综合离子束分析系统,可进行卢瑟福背散射、核反应分析和粒子诱发X射线分析3种离子束分析方法的综合应用.利用该方法,对Fe合金样品中杂质元素的含量和部分元素的深度分布进行了测量.6 MV EN串列加速器是牛津大学赠于北京大学,为许多基础和应用研究提供了支持,其主要用于加速器质谱、离子辐照以及离子束分析工作,也可以用来对探测器进行刻度.随着现代离子束分析技术和多束离子辐照装置的发展,3台加速器将为科研提供更好的技术支持.Electrostatic accelerators are powerful tools in many research fields,such as nuclear physics,materials science,and archaeology.Three electrostatic accelerators,the 1.7 MV tandem,the single stage Van de Graaff with a terminal voltage of 4.5 MV,and the EN tandem with a terminal voltage of 6 MV,were installed in 1980s and have been put into operation since the early 1990s at Peking University.The 1.7 MV tandem accelerator is equipped with a radio frequency charge exchange negative ion source and a cesium sputtering negative ion source,which can produce most of the ions from H to Au.It accelerates the ions to energies from several hundreds of keV to several MeV.The accelerator is used for ion irradiation,ion beam modification of materials,as well as ion beam analysis(IBA),such as Rutherford backscattering spectroscopy(RBS)and channeling.Many significant achievements have been made by using the ion irradiation beamline,especially in the research of nuclear materials.The superlattice steel containing a high density of B2-ordered Ni(Al,Fe)superlattice nanoprecipitates(NPs)was irradiated with 6 MeV Au ions at different high temperatures.The superlattice steel exhibits extraordinary radiation tolerance,namely,zero void swelling at 400-600℃ under an average radiation damage of up to 2350 dpa,outperforming most of the other steels studied to date.This paper demonstrates a counterintuitive strategy to enhance the radiation resistance of metallic materials by simply ordered superlattice NPs.For the 4.5 MV electrostatic accelerator,the isotope ions of hydrogen or helium can be produced in the energy range of 0.7-3.8 MeV,and continuous or pulsed quasi-monoenergetic neutron fields(0.03-7 MeV,14-19 MeV)can be generated by ion beam bombarding targets.The neutron fields have applied it to measure(n,α)reaction cross section.Based on the 4.5 MV electrostatic accelerator,a total-IBA system has been established.Total-IBA can obtain self-consistency results through analyzing spectra of different emission particles,without massive mo

关 键 词：静电加速器 离子辐照 核能材料 离子束材料改性 离子束分析 

分 类 号：TL52[核科学技术—核技术及应用]