n型硅脉冲激光掺铟的物理过程与缺陷特性研究

用Nd-YAG脉冲激光对n型硅掺铟,形成外p⁺n结。利用二次离子质谱仪(SIMS)、卢瑟福背散射(RBS)等方法,研究了硅内铟的分布,并分析了用20ns脉冲激光硅掺铟的物理过程,发现当激光能量密度足够大时,在硅表面层存在硅-铟混合熔体和液态硅两部分。当激光能量密度较小时,硅表面层仅有液态硅层、用I-V,C-V和深能级瞬态谱(DLTS)等方法研究了p⁺n结的电学性质,发现在p⁺n结的n区存在两个缺陷。一个能通过快速热退火,在600℃,60s条件下消失,研究表明可能为空位与杂质的复合体。另一个通过快速热退火不能消失,可能与位错有关。 关键词：     

回旋加速器虚拟样机技术进展

基于缩短开发周期、降低物理样机成本及实现创新设计的目的, 虚拟样机(VP)技术被用于低能回旋加速器的设计中. 本文介绍了华中科技大学在回旋加速器VP技术研究上的进展. 提出了面向多学科协同设计的回旋加速器虚拟样机开发思路, 描述了基于Python脚本语言混合编程技术的VP集成平台. 在该平台下, 通过多个设计组件的支持与协作, 可实现对主磁铁、高频腔和中心区等关键部件及回旋加速器整机的优化设计.     

Central region design for a 10 MeV internal ion source cyclotron

Internal ion sources are widely adopted in commercial cyclotrons used for short-life isotopes production. Without beam manipulation provided by the external beam injection line, the central region of this type of cyclotron is more sensitive and should be carefully designed. A design study and beam dynamics simulation for the central region of a 10 MeV compact cyclotron is presented. The OPERA3D/TOSCA code was used to calculate the electric field from a parameterized three dimensional （3D） central region model. With iterative structure optimizations of the central region, the beam centering and vertical focusing is well controlled, and the RF phase acceptance is around 25°. A c＋＋ code for beam simulation in the central region was developed and tested.     

用于中性束注入的大功率射频离子源激励器研制

建立了一个等离子体射频激励器,工作气体为氢气,工作气压为0.3Pa,激励器陶瓷桶直径300mm,工作频率1MHz。实现了RF等离子体激发放电,在输入射频功率16kW条件下,采用朗缪尔探针测得的等离子体密度>10¹⁸m^-3,初步建立了一个RF等离子体源实验平台。     

大功率RF 离子源阻抗匹配电路的设计与实现

在大功率RF 离子源中,激励器的作用是产生等离子体,阻抗匹配电路是激励器吸收RF 功率的关键。将激励器等效阻抗视为一个电阻和一个电感的串联,采用了一种由一个RF 变压器并和两个可调电容组成的阻抗匹配电路,给出了视RF 变压器为理想变压器时阻抗匹配电路的分析模型,推导了阻抗匹配时两个可调电容的电气参数。当激励器实验装置使用一个石英玻璃激励器时,搭建了一个阻抗匹配电路,成功地将RF 功率耦合进激励器并产生了等离子体。     

A permanent magnet electron beam spread system used for a low energy electron irradiation accelerator

The development of irradiation processing industry brings about various types of irradiation objects and expands the irradiation requirements for better uniformity and larger areas. This paper proposes an innovative design of a permanent magnet electron beam spread system. By clarifying its operation principles, the author verifies the feasibility of its application in irradiation accelerators for industrial use with the examples of its application in electron accelerators with energy ranging from 300 keV to 1 MeV. Based on the finite element analyses of electromagnetic fields and the charged particle dynamics, the author also conducts a simulation of electron dynamics in magnetic field on a computer. The results indicate that compared with the traditional electron beam scanning system, this system boosts the advantages of a larger spread area, non-power supply, simple structure and low cost, etc., which means it is not only suitable for the irradiation of objects with the shape of tubes, strips and panels, but can also achieve a desirable irradiation performance on irregular constructed objects of large size.     

回旋加速器虚拟样机技术进展

基于缩短开发周期、降低物理样机成本及实现创新设计的目的,虚拟样机(VP)技术被用于低能回旋加速器的设计中.本文介绍了华中科技大学在回旋加速器VP技术研究上的进展.提出了面向多学科协同设计的回旋加速器虚拟样机开发思路,描述了基于Python脚本语言混合编程技术的VP集成平台.在该平台下,通过多个设计组件的支持与协作,可实现对主磁铁、高频腔和中心区等关键部件及回旋加速器整机的优化设计.