HIRFL改造中的加速器物理问题

从加速器运行的角度对兰州重离子加速器 HIRFL建成以来所存在的问题进行了总结 ,结合放射束物理和冷却储存环 CSR对 HIRFL的新要求 ,从加速器的物理设计方面提出了一些改进方案 .主要问题有 :超低能束流传输的空间电荷效应的影响 ,扇聚焦回旋加速器 SFC高频加速电压不对称对束流轨道的影响 ,用半频聚束的方式补偿两台回旋加速器的纵向不匹配 ,前束线上聚束器的工作模式的选取 ,强杂散磁场对超低能和低能束流传输的影响 ,分离扇回旋加速器 SSC注入区过垫补磁场对注入束流轨道的影响 ,SFC和 SSC的单圈引出 ,重离子通过剥离膜后的束流损失和束流品质的变坏等.From the viewpoints of the HIRFL operation and the new requirements to HIRFL by the study of radioactive beam physics and CSR project, the HIRFL upgrading program has been proposed after studying the existing problems found during the operation and new problems when increasing the beam intensιty and ion variety. The accelerator physics problems of the upgrading program were discussed here, which include the space charge effect on the very low energy beam line...     

兰州重离子加速器冷却储存环

 兰州重离子加速器(HIRFL)由用作注入器的扇聚焦回旋加速器(SFC)和分离扇回旋加速器(主加速器SSC)组成,是加速中、低能重离子束流的回旋加速器系统.     

兰州重离子加速器综述

兰州重离子研究装置(HIRFL)是由离子源,注入器(扇聚焦回旋加速器,SFC)和主加速器(分离扇回旋加速器,SSC)组成的。由离子源产生的束流经过注入器SFC的预加速后,通过前束流线注入到主加速器SSC,束流在主加速器加速到最大能量后,由后束流线送到各个实验终端。本文首先介绍了HIRFL的建造过程、束流特性和主要结构。然后描述了SSC和束流线的调束过程、调束方法及运行状态。最后展望了HIRFL广泛的应用前景。     

HIRFL的束流品质

HIRFL兰州重离子研究装置(HIRFL)包括一台能量常数K=69的扇聚焦回旋加速器(SFC)作为注入器,和一台能量常数K=450的分离扇回旋加速器(SSC)作为主加速器。SFC 和SSC 之间有60米的前束流线(L_1)相连,沿L_1装有1个剥离器和2个聚束器.束流从SSC通过后束流线(L_2)被引导到实验大厅........     

CSR空间电荷效应的研究

针对兰州重离子加速器冷却储存环的流强设计 ,对其空间电荷效应进行了讨论 .随着流强增高和发射度降低 ,束流自作用场效应 (空间电荷效应 )逐渐显现 .散焦的空间电荷力造成的粒子自由振荡频移和束流包络增长 ,带来了不稳定因素 ,这些不稳定因素就限定了储存环的流强极限.Cooler Storage Ring (CSR), an upgrading program planned at the Heavy Ion Research Facility in Lanzhou (HIRFL), will supply beams with higher quality and intensity. Space charge effects should be considered due to this magnitude of intensity in CSR. The concept and some phenomena of space charge effects are discussed. Space charge intensity limit and space charge tune shift of normal CSR operation are given. It is of significance for the construction and operation of the future facility.     

HIRFL与CSR的匹配研究

国家重大科学工程HIRFLCSR冷却储存环计划主环CSRm利用已有的HIRFL作为注入器,为了更好地利用HIRFL加速器的能力,对这两台加速器的匹配在原来的初步考虑的基础上进行了较为详细的研究,提出了分别利用HIRFL自己的注入器SFC单独注入到CSR以及SFC加上主加速器SSC注入到CSR的两套方案,既可以提高HIRFL与CSR的总传输效率,又可以在SFC与CSR联合运行的同时使SSC与另建的小回旋加速器组合加速质子,从而充分提高HIRFL的运行效率.     

HIRFL Operation and Upgrade

After almost one year shutdown for upgrading the vacuum chamber of the iniector SFC,SFC has been in operation separately since May 2003. The SFC operation statistics and accelerated heams from May to December 2003 are shown in Table 1 and 2. The main cyclotron SSC has beenfor still shut down in 2003 for upgrading the SSC power supply system, control and diagnostic system, and themain experimental area, LECR3, an ECR ion source dedicated for atomic physics and surface physics research, has provided 2488 hours beams for experiments of atomic physics research.     

HIRFL–CSR加速器中束流与真空中剩余气体的碰撞损失

研究了重离子加速器中束流与真空中剩余气体的碰撞损失过程和碰撞截面,在依据大量实验数据的基础上,提出了一组计算离子一原子的电荷交换截面的经验公式.以兰州重离子加速器HDRFL及冷却储存环CSR为例,给出了依据碰撞截面的公式计算束流在加速器真空中的传输效率的方法,并计算了在不同真空度下HIRFL的ECR源轴向注入束运线、注入器SFC、前束运线、主加速器SSC和后束运线等不同加速阶段及CSR的传输效率,并提出合理的真空度要求.HIRFL的真空分布测量和束流的损失测量证明了该计算方法的可靠性.     

SFC新引出系统的物理设计研究

兰州重离子加速器(HIRFL)是一个回旋加速器组合系统. 它的注入器是K=69的扇聚焦回旋加速器.在十多年运行过程中, 曾做过两次较大的改进, 使加速的束流种类及流强都有了显著的改善.但由于SFC的引出效率比较低, 只有30%左右, 一方面损失了大量束流, 另一方面许多束流损失在引出静电偏转板上, 造成了大量出气, 破坏了真空, 难以维持长期大束流运行. 文章重新对SFC引出系统进行了物理设计研究, 在真实磁场的基础上做了大量计算工作, 得到了一个新的引出 系统方案.     

基于HIRFL-CSR中剥离器的支束线物理设计

介绍了通过剥离器后不同电荷态的束流在弯曲磁铁中的传输情况,由此引出一种切割束流的方法,在此基础上设计了一条支束线,以实现两个实验终端同时供束,增加供束时间.在束运线设计过程中,根据HIRFL CSR的实际条件,对束流的中心轨迹和束流包络做了详细的计算,给出了束流输运线的几何布局和各个元件的基本物理参数. A new branch beam line downstream of the stripper located between SFC and SSC is designed to collect the beams with the charge states other than the most intensive one. The layout of the branch beam line and the physical parameters for each dipole and quadrupole are given based on careful calculations.     

HIRFL新的束流分配系统

随着CSR的建成和兰州重粒子加速系统(HIRFL)实现质子加速,HIRFL现有的束流传输系统已不能满足越来越多的物理实验对供束时间的要求,为此,对原有的HIRFL的束流输运系统进行了分时供束改造,新的束流分配系统可以在给CSR供束和不供束两种情况下,同时使用SFC和SSC的束流在多个实验终端进行物理实验,介绍了新设计的HIRFL束流分配系统的布局和束流光学计算结果.     

New Beam Distribution System

With construction of CSR and acceleration of proton at HIRFL, the existing beam handling system can not meet the requirements of nuclear physics experiments for more and more beam time. For this reason, a new beam distribution system based on time is being constructed. The new system not only deliuers beams to the new terminals for reaser-ch program of proton and heavy ion therapies, single particle effects of spaceflight electronics components and irradiration effecs of living things, but also can provide beams for CSR when physics experiments are done on the experimental terminals with the beam from both SFC and SSC. The layout, performance and beam optics calculations of the new distribution system are presented.     

MSC1210电源控制器的程序优化

为了解决兰州重离子研究装置( HIRFL ) 电源控制系统中的MSC1210 控制模块在调束过程中出现的各种故障,对其主芯片程序进行了优化设计。首先介绍了控制器的各种故障现象,分析了形成原因,然后制定了详细的设计方案,最后采用了以状态机为基础的指令接收过程、带校验机制的通信方式及远程指令复位等方法进行程序优化。实验室测试和现场使用结果表明,优化后的控制器运行稳定可靠,满足加速器的需求。The MSC1210 control module is one of the most important power supply controllers of Heavy Ion Research Facility in Lanzhou ( HIRFL ), but there are several problems during beam tuning. In order to deal with the problems,the main chip’s program was redesigned. In this paper we introduced the controller’s fault phenomena, and analyzed the reasons; then scheduled the optimized program in detail. Several methods were employed to improve the system performance, including instruction receiving process which is based on state machine, the communication mode with parity mechanism, and the remote instruction reset method. Both laboratory and commissioning tests indicate that the optimized controller is stable and reliable, and meet the operation requirement of HIRFL.     

新核素合成、高激发热核和放射性束物理前沿再获一批重要成果

综述了中国科学院近代物理研究所最近三年来在新核素合成、高激发热核和放射性束物理前沿领域取得的重要进展．其主要成果是在兰州重离子加速器和放射性束流线上获得的.The recent remarkable achievements in IMP in the research frontiers of synthesis of new nuclides, highly excited hot nuclei and radioactive ion beam physics are reviewed. Most of the achievements are made at the HIRFL and RIBLL of IMP.     

Beam transport experiment with a new kicker control system on the HIRFL

A kicker control system is used for beam extraction and injection between two cooling storage rings(CSRs) at the Heavy Ion Research Facility in Lanzhou(HIRFL). To meet the requirements of special physics experiments, the kicker controller has been upgraded, with a new controller designed based on ARM+DSP+FPGA technology and monolithic circuit architecture, which can achieve a precision time delay of 2.5 ns. In September2014, the new kicker control system was installed in the kicker field, and the test experiment using the system was completed. In addition, a pre-trigger signal was provided by the controller, which was designed to synchronize the beam diagnostic system and physics experiments. Experimental results indicate that the phenomena of "missed kick"and "inefficient kick" were not observed, and the multichannel trigger signal delay could be adjusted individually for kick power supplies in digitization; thus, the beam transport efficiency was improved compared with that of the original system. The fast extraction and injection experiment was successfully completed based on the new kicker control systems for HIRFL.     

HIRFL的辐照治癌终端

为了进行重离子束流的肿瘤治疗和生物效应的研究,HIRFL正在建造一个辐照治癌终端.主要介绍了该终端的束流制备方法和束流线的布局、性能参数和束流光学设计计算结果. A new experimental terminal is being constructed at HIRFL for research program of proton and heavy ion therapies and irradiation effects of living things . The beam preparation method and the layout, performance and beam optics calculation of the beam line are presented.     

放射性核束物理与核天体物理

基于兰州重离子加速器国家实验室 (HIRFL )的中能放射性核束线 (RIBLL)及北京串列加速器国家实验室 (HI- 1 3 )的低能放射性核束线 (GIRAFFE) ,开展放射性核束物理和核天体物理研究 ,拟解决的关键科学问题是 :远离β稳定线核的结构与反应 ;超重新核素及近滴线核素的合成和性质研究 ,极端同位旋非对称核物质特性和关键的天体核反应研究 .研究内容分成 7个课题 :(1 )晕核研究 ;(2 )新核素合成及超重新核素研究 ;(3 )丰中子核结构和反应 ;(4)丰质子核结构和反应 ;(5 )高自旋的同位旋相关性 ;(6 )关键天体核反应 ;(7)系统的理论研究 .上述研究也将是2005年建成的国家大科学工程——兰州冷却贮存环的主要科学目标的研究基础 .简述了近期的主要工作进展. Based on the intermediate energy radioactive Ion Beam Line in Lanzhou (RIBLL) of Heavy Ion Research Facility in Lanzhou(HIRFL) and Low Energy Radioactive Ion Beam Line (GIRAFFE) of Beijing National Tandem Accelerator Lab (HI-13) the radioactive ion beam physics and nuclear astrophysics will be researched in detail. The key scientific problems which will be researched as high priority are: the nuclear structure and reaction for nucleus far from β-stability line; the syntheses...