北京大学1.7 MV串列静电加速器的离子注入/辐照实验系统  

Ion Implantation/Irradiation System of 1.7 MV Tandem Accelerator at Peking University

作　　者：徐川 付恩刚 XU Chuan;FU Engang(Department of Technical Physics,School of Physics,State Key Laboratory of Nuclear Physics and Technology,Peking University,Beijing 100871,China)

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

出　　处：《原子核物理评论》2021年第4期410-415,共6页Nuclear Physics Review

基　　金：国家重点研发计划项目(2019YFE03120003,2017YFE0302500,2018YFE0307100);国家自然科学基金资助项目(11975034,11921006,U20B2025,U21B2082)。

摘　　要：北京大学1.7MV串列静电加速器运行至今已有三十多年。该加速器配备有高频电荷交换负离子源和铯溅射负离子源,能够引出从H到Au之间的大部分元素的离子。离子能量可被加速至几百keV到若干MeV,主要开展离子注入/辐照实验和卢瑟福背散射(RBS)和沟道分析等离子束分析工作。基于辐照实验需求,建立了高温辐照系统,温度最高可达950℃。为了实现更加精确的离子注入,设计了直接式与间接式两种法拉第杯结构,使束流扫描面积精确控制,并且在测量束流强度时除了抑制次级电子,还考虑到了次级正离子的影响。利用不同能量的Au离子在单晶Si片上进行了注入实验,通过RBS分析显示测量剂量与期望剂量误差在4%以内,此外,注入均匀性的测试表明注入剂量的相对标准偏差为2%。The 1.7MV tandem accelerator at Peking University has been running for more than 30 years. The accelerator is equipped with a Radio Frequency(RF) charge exchange negative ion source and a cesium sputtering negative ion source, which can produce most of the ions from H to Au. It can accelerate the ions to energies from several hundreds of ke V to several Me V. The accelerator is used for ion implantation and irradiation as well as for ion beam analysis, such as Rutherford Backscattering Spectroscopy(RBS) and channeling. Based on the experimental requirements, a high temperature irradiation system was established, with the highest temperature of 950 ℃. In order to achieve more accurate ion implantation, two Faraday cup structures, direct type and indirect type, are designed. The scanning area of the beam is controlled accurately. These designs can not only suppress the secondary electrons, the influence of secondary positive ions is also considered when measuring the beam intensity.The ion implantation experiments of Au ions with different energy on single crystal silicon were carried out. RBS analysis shows that the error between the measured fluence and the expected fluence is within 4%. In addition, the uniformity measurement shows that the relative standard deviation of the implant fluence is 2%.

关 键 词：串列静电加速器 离子注入/辐照 法拉第杯 卢瑟福背散射分析 

分 类 号：TL52[核科学技术—核技术及应用] O571[理学—粒子物理与原子核物理]