【作者】 闫芳；

【导师】 樊胜； 关遐令；

【作者基本信息】 中国原子能科学研究院 ， 粒子物理与原子核物理， 2006， 硕士

【摘要】 本论文包括两个部分，第一部分是串列加速器头部电极的改进方案，第二部分是串列升级工程在线同位素分离器(ISOL)靶-源中靶材料的研究。中国原子能科学研究院的HI-13串列加速器于1987年10月正式运行至今，头部打火一直是制约头部电压提升的重要原因。继2004年10月加速管改造之后决定进一步采用改变头部电极形状的方式来降低头部表面电场强度、提升头部电压，将头部电极的开放式鼠笼结构改变为一个闭合的整体，去掉等压环，电极边缘用椭圆形状过渡到均压环的位置。本工作采用superfish软件包中的poisson软件计算几种可能形状下表面电场的分布，给出“只改变头部电极形状不改变均压环尺寸”以及“改变头部形状同时改变均压环尺寸”两种情况下的最佳改进方案。在串列升级工程中，在线同位素分离器(ISOL)前接回旋加速器，后接串列加速器及后加速系统，是十分关键的部分，其中的高温、强放射性靶-源装置是该项目的关键技术之一。因为涉及到强放射性及放射性核素的释放问题，靶材料及靶-源结构材料的确定是一个重要的问题。目前候选的材料有天然铜、铝、钼、铅、钨、钽、铀、石墨、水、不锈钢等。在工作条件下，靶材料或结构材料与100MeV、200μA强流质子束相互作用是否会产生我们所感兴趣的放射性核素；有没有难于处理的长寿命放射性核素；冷却指定时间段以后剂量水平能否下降到可接受的范围，这些问题都是靶的设计、更换以及后期处理需要的依据。本工作采用LCS结合C-BURN程序精确计算除铀靶之外的候选靶材料及结构材料与100MeV、200μA强流质子束相互作用所产生的放射性核素活度及射线强度；利用SHIELD程序计算给出铀靶与质子束相互作用出射不同射线的辐射强度及γ射线能谱，并利用CYF+核反应网络方程(NETWORK)计算给出铀靶在质子束照射后产生的γ射线辐射强度，同时利用LCS理论模块结合C-BURN程序估算出铀靶在质子束照射后产生的γ射线辐射强度及其能谱，并将三种不同计算方法给出的结果进行比较。更多还原

【Abstract】 This article consists of two parts, one is modification project of the terminal electrode in HI-13 tandem accelerator, another is investigation of target materials for target-source of ISOL.The HI-13 tandem accelerator of China Institute of Atomic Energy has been running since October 1987, the discharging between terminal electrode and ground has always been a primary restricting cause in the lifting of terminal voltage. After the upgrade of acceleration tube in October 2004, It has been proposed that the voltage on terminal electrode can be lifted by reducing the surface electrostatic field and modification of the shape of terminal electrode from opening cat cage to a close whole part, discarding the equipotential rings, extending the elliptical edge of terminal electrode to the position of 0# equipotential rings.In this work the surface electrostatic field distributing of several possible shapes of the terminal electrode are calculated with Poisson code of Superfish software, two type of optimized modification configuration in different situation are suggested: one is modification the shape of terminal electrode only, another is modification the shape of equipotential rings and the shape of terminal electrode.In the upgrading project of tandem accelerator, Isotope Seperated On Line (ISOL) is a critical part, as it connecting cyclotron in the front and tandem accelerator and post accelerated system at back. The high temperature and strong radioactivity target-source system is one of the critical techniques in ISOL.At present, the candidate target materials are natural Copper, Aluminum, Molybdenum, Lead, Tungsten, Tantalum and Uranium, the candidate configuration materials are Carbon, Water, Stainless steel. Such questions should be investigated: can the interaction of targets with 100MeV, 200μA intense proton beams produce interestedradioactive nuclides, is there any long-life radioactive nuclides, can the radioactivity level fall to an accepted level? This work intends to provide some references for the design and maintenance of target ion source.In this work the radioactive nuclides activity and ray intensity produced by the interaction of candidate target materials and body materials except Uranium with 100MeV,200μA intense proton beams are calculated by LCS+C-BURN code, Also the activity ofradioactive nuclides and ray intensity produced by the interaction of uranium target with intense proton beams are calculated by SHIELD code and CYF+NETWORK code. All of the results are compared with the results calculating by the theoretical module of LCS combining with C-BURN code.更多还原