An integrating current transformer for fast extraction from the HIRFL-CSR main ring

For any experiment that uses the beam of an accelerator, monitoring the beam intensity is always art important concern. It is particularly useful if one can continuously measure the beam current without disturbing the beam. We report here on test experiments for an Integrating Current Transformer (ICT) used to measure fast extraction beams from the HIRFL-CSR main ring (CSRm). The laboratory tests and beam intensity measurement results are presented in this paper. The influence of the kicker noise is also analyzed.

Ultrahigh compression of water using intense heavy ion beams: laboratory planetary physics

Intense heavy ion beams offer a unique tool for generating samples of high energy density matter with extreme conditions of density and pressure that are believed to exist in the interiors of giant planets. An international accelerator facility named FAIR (Facility for Antiprotons and Ion Research) is being constructed at Darmstadt, which will be completed around the year 2015. It is expected that this accelerator facility will deliver a bunched uranium beam with an intensity of 5x10(11) ions per spill with a bunch length of 50-100 ns. An experiment named LAPLAS (Laboratory Planetary Sciences) has been proposed to achieve a low-entropy compression of a sample material like hydrogen or water (which are believed to be abundant in giant planets) that is imploded in a multi-layered target by the ion beam. Detailed numerical simulations have shown that using parameters of the heavy ion beam that will be available at FAIR, one can generate physical conditions that have been predicted to exist in the interior of giant planets. In the present paper, we report simulations of compression of water that show that one can generate a plasma phase as well as a superionic phase of water in the LAPLAS experiments.

Experimental Study on the Exotic Structure of N-12 in RIBLL

We measured the total reaction cross sections of N-12 in Si at 36.2 MeV/u. using Radioactive Ion Beam Line in Lanzhou (RIBLL) with a new method. The reaction target was installed at the intermediate focusing point T1 at RIBLL. This scheme allows us to identify particles before and after the reaction target unambiguously. The total reaction cross section (1760 +/- 78mb) of N-12 in Si is obtained. Assuming that N-12 consists of a core C-11 plus one halo proton, the excitation function of N-12 on the Si and C targets is calculated with the Glauber model and the Fermi-Fermi density distributions. It can fit the experimental data very well. A large diffusion of the protons density distribution supports the halo structure for N-12.

Production of highly charged ion beams with SECRAL

Superconducting electron cyclotron resonance ion source with advanced design in Lanzhou (SECRAL) is an all-superconducting-magnet electron cyclotron resonance ion source (ECRIS) for the production of intense highly charged ion beams to meet the requirements of the Heavy Ion Research Facility in Lanzhou (HIRFL). To further enhance the performance of SECRAL, an aluminum chamber has been installed inside a 1.5 mm thick Ta liner used for the reduction of x-ray irradiation at the high voltage insulator. With double-frequency (18+14.5 GHz) heating and at maximum total microwave power of 2.0 kW, SECRAL has successfully produced quite a few very highly charged Xe ion beams, such as 10 e mu A of Xe37+, 1 e mu A of Xe43+, and 0.16 e mu A of Ne-like Xe44+. To further explore the capability of the SECRAL in the production of highly charged heavy metal ion beams, a first test run on bismuth has been carried out recently. The main goal is to produce an intense Bi31+ beam for HIRFL accelerator and to have a feel how well the SECRAL can do in the production of very highly charged Bi beams. During the test, though at microwave power less than 3 kW, more than 150 e mu A of Bi31+, 22 e mu A of Bi41+, and 1.5 e mu A of Bi50+ have been produced. All of these results have again demonstrated the great capability of the SECRAL source. This article will present the detailed results and brief discussions to the production of highly charged ion beams with SECRAL.

New development of advanced superconducting electron cyclotron resonance ion source SECRAL (invited)

Superconducting electron cyclotron resonance ion source with advance design in Lanzhou (SECRAL) is an 18-28 GHz fully superconducting electron cyclotron resonance (ECR) ion source dedicated for highly charged heavy ion beam production. SECRAL, with an innovative superconducting magnet structure of solenoid-inside-sextupole and at lower frequency and lower rf power operation, may open a new way for developing compact and reliable high performance superconducting ECR ion source. One of the recent highlights achieved at SECRAL is that some new record beam currents for very high charge states were produced by 18 GHz or 18+14.5 GHz double frequency heating, such as 1 e mu A of Xe-129(43+), 22 e mu A of Bi-209(41+), and 1.5 e mu A of Bi-209(50+). To further enhance the performance of SECRAL, a 24 GHz/7 kW gyrotron microwave generator was installed and SECRAL was tested at 24 GHz. Some promising and exciting results at 24 GHz with new record highly charged ion beam intensities were produced, such as 455 e mu A of Xe-129(27+) and 152 e mu A of Xe-129(30+), although the commissioning time was limited within 3-4 weeks and rf power only 3-4 kW. Bremsstrahlung measurements at 24 GHz show that x-ray is much stronger with higher rf frequency, higher rf power. and higher minimum mirror magnetic field (minimum B). Preliminary emittance measurements indicate that SECRAL emittance at 24 GHz is slightly higher that at 18 GHz. SECRAL has been put into routine operation at 18 GHz for heavy ion research facility in Lanzhou (HIRFL) accelerator complex since May 2007. The total operation beam time from SECRAL for HIRFL accelerator has been more than 2000 h, and Xe-129(27+), Kr-78(19+), Bi-209(31+), and Ni-58(19+) beams were delivered. All of these new developments, the latest results, and long-term operation for the accelerator have again demonstrated that SECRAL is one of the best in the performance of ECR ion source for highly charged heavy ion beam production. Finally the future development of SECRAL will be presented.

The Compact Pulsed Hadron Source: A Design Perspective

During the past. decades, large-scale national neutron sources have been developed in Asia, Europe, and North America. Complementing such efforts, compact hadron beam complexes and neutron sources intended to serve primarily universities and industrial institutes have been proposed, and some have recently been established. Responding to the demand in China for pulsed neutron/proton-beam platforms that are dedicated to fundamental and applied research for users in multiple disciplines from materials characterization to hadron therapy and radiography to accelerator-driven sub-critical reactor systems (ADS) for nuclear waste transmutation, we have initiated the construction of a compact, yet expandable, accelerator complex-the Compact Pulsed Hadron Source (CPHS). It consists of an accelerator front-end (a high-intensity ion source, a 3-MeV radio-frequency quadrupole linac (RFQ), and a 13-MeV drift-tube linac (DTL)), a neutron target station (a beryllium target with solid methane and room-temperature water moderators/reflector), and experimental stations for neutron imaging/radiography, small-angle scattering, and proton irradiation. In the future, the CPHS may also serve as an injector to a ring for proton therapy and radiography or as the front end to an ADS test facility. In this paper, we describe the design of the CPHS technical systems and its intended operation.

STATUS AND PROSPECTS OF HIRFL EXPERIMENTS ON NUCLEAR PHYSICS

HIRFL is an accelerator complex consisting of 3 accelerators, 2 radioactive beams lines, 1 storage rings and a number of experimental setups. The research activities at HIRFL cover the fields of radio-biology, material science, atomic physics, and nuclear physics. This report mainly concentrates on the experiments of nuclear physics with the existing and planned experimental setups such as SHANS, RIBLL1, ETF, CSRe, PISA and HPLUS at HIRFL.

同步加速器磁场电源控制系统的优化研究

CSR控制系统是一个基于网络的分布式控制系统，它是由许多分控制系统组成。磁场电源控制系统是CSR控制系统中很重要的一部分，它是一个波形发生、数据采集系统。所有依赖波形控制的系统都可以由它来控制。波形的参数由物理学家根据实验需要计算得出。因为加速器所有的运行状态都被电源所控制，所以控制系统的直接控制对象就是磁场电源。在整个控制系统中最重要的就是控制波形的同步和波形的精度，这是同步加速器控制系统的关键所在。波形的同步由同步时序系统控制，这是CSR成功运行的决定条件。数据的采集、电源状态的监测由数据采集模块CPLD负责完成，与前端ARM控制器结合，形成数据的上行通道。采集到的数据均存放在中央控制室的数据库中，以供参考、后期分析及应用。论文论述了对CSR磁场电源控制系统、时序系统和软件系统的设计实现及优化改进

三相高压变压器型电子加速器性能研究

在当前国际上，强流大功率电子加速器的研究是应用于辐射行业辐射源的一个主要研究方向。内置加速管三相高压变压器型电子加速器与外置加速管强流大功率电子加速器相比，具有结构紧凑、造价低、结构简单等特点。本文对内置加速管三相变压器型电子加速器在研制过程中出现的高压击穿频繁、高压硅堆的损坏率高、能量脉动高、引出窗束流损失大等问题进行了研究，提出并实施了改进措施，得到了较好的调试结果。并对存在的问题进一步提出了改进方案。首先介绍了内置加速管三相变压器型电子加速器的原理、结构及组成。在此基础上，针对在加速器调试过程中出现的经常性高压击穿等严重制约加速器正常运行的问题，通过对三相高压变压器型的高压发生器在变压器特性分析、气体绝缘和电场分布计算、高压电极形状优化、过电压分布的计算、正常工作时的仿真，提出了改进方案。经过改进后，从调试结果来看，所设计的高压发生器能够正常稳定的工作。研究了作为高压发生器易损坏的关键部件之一的高压整流硅堆的性能。根据硅堆内部的结构和在高压发生器中所处的位置，合理的建立了等效电路，并对电路中各结构电容在硅堆耐高压方面的作用进行了详细的理论计算和分析。对硅堆内部管芯的排列及在加速器中的摆放位置提出了改进方案，经过改进，提高了硅堆的耐压值，也保证了高压发生器的正常稳定运行。对于加速器引出窗束流损失大和能量脉动高的问题，用PBGUN程序计算了优化后的阴极鼻锥聚束极结构在强流状态下的束流轨迹和加速管出口处的束斑；对能量脉动测量做了分析，并得到较真实的脉动值。论文最后对内置加速管三相变压器型电子加速器在整体调试中存在电子束受到变压器杂散磁场影响的问题做了介绍，提出了分离式的改进结构

高压变压器型电子加速器理论与实验研究

根据工业辐照对大功率电子加速器的需求，中科院近物所开展了高压变压器型DG系列电子加速器的研制。本文的主要工作是围绕其中两个型号DG-1.2（1.2MeV/40mA）和DG-2.5（2.5MeV/40mA）的研制及产业化而展开的研究。该类型电子加速器具备技术和市场优势， DG系列的研制成功，必将推动我国辐照加工业的发展。论文重点研究了基于空心变压器结构高压发生器的性能，改进了线圈、磁路结构，提高了发生器耦合效率；优化了高压电极结构，改善了电极周围电场分布，提升了发生器的绝缘性能，并评估了发生器高压击穿故障时的特性；选取了匹配的无功补偿方式，提高了发生器的功率因数。设计出新型热辐射间热式强流电子枪，研究了六硼化镧、六硼化镧钡两种材料热阴极的发射特性，均获得300mA以上的稳定束流发射。分析了DG型束流加速、传输结构，改进了引出系统结构，提高了束流引出效率；构建了基于PLC的工业化加速器控制系统，运行状况良好。通过专家测试，DG-1.2型已经达到设计参数1.2MeV/40mA，并能够稳定运行在1.2MeV/50mA；DG-2.5型，1.6MeV/30mA下通过测试，能够调试到2.0MeV/40mA。 最后，分析了DG系列电子加速器的进一步发展方向，初步确定了DG加速器的产业化目标

强流扇聚焦回旋加速器中空间电荷效应的研究

本文比较系统地介绍了扇聚焦回旋加速器内部的束流动力学及其注入系统的一般理论，并结合两台具体的扇聚焦回旋加速器的设计讨论了在回旋加速器以及静电反射镜内空间电荷效应对束流的影响。第一章简单介绍了回旋加速器的发展历史及分类、强流回旋加速器的应用，加速器驱动系统ADS(Accelerator Driving System)、能量放大器EA(Energy Amplifier)方案以及本文工作的主要内容。第二章首先介绍了扇聚焦回旋加速器的基本理论，包括扇聚焦回旋加速器内的轨道理论(静态平衡轨道及加速轨道性质)以及相空间的描述方法等。然后详细讨论了回旋加速器内空间电荷效应的影响及研究方法，包括空间电荷作用下粒子的运动方程、空间电荷电场的不同种类、求解空间电荷电场的基本方法和模型以及空间电荷效应对束流轨道特性和相空间传输特性的影响等。在本章的第4节中，介绍了两台强流扇聚焦回旋加速器(50MeV-6mA H_2~+超导扇聚焦回旋加速器和17MeV-2mA H~-扇聚焦回旋加速器)的具体设计步骤和计算结果,讨论了这两台扇聚焦回旋加速器中加速轨道和相空间的传输以及空间电荷效应的影响。最后，简单介绍了设计时所使用的两个计算程序AGORA_SCE和CINEZ_SCE。第三章首先简单介绍了用于扇聚焦回旋加速器的各种注入方法以及在轴向注入时所采用的不同种类的静电偏转镜。然后详细介绍了目前最常用的螺旋扇型静电偏转镜的基本工作原理，如参考粒子的运动轨道及偏转镜的光学性质等，讨论了螺旋线型静电偏转镜中空间电荷效应的影响。最后仍然以50MeV-6mAH_2~+和17MeV-2mA H~-这两台扇聚焦回旋加速器为例，对它们的静电偏转镜进行了设计，并分别研究了它们在空间电荷效应影响下的轨道特性及相空间传输特性。第四章简单介绍了工作中所用到的一些计算工具，如三维电磁场计算程序MAFIA以及等时场分析程序EQUIL，并给出了17MeV-2mA H~-扇聚焦回旋加速器的等时场的计算结果。论文的最后部分简单总结了本文的工作，并提出了今后进一步的工作设想。

加器束流强度和能量稳定控制系统

本文基于中国科学院的代物理研究所电子辐照室的谐振变压器型电子加速器计算机控制系统的研制工作。首先介绍了研制此种加速器的国际、国内的历史背景和前景，接着介绍了加速器的结构和工作原理，描述了加速器的计算机控制系统，着重介绍了加速器的束流强度稳定系统和能量稳定系统。在束流强度稳定系统中，首先介绍了束流稳定系统的工作原理、实现的方法和对灯丝加热电源的要求；通过对灯丝电源的控制达到对束流强度调节和稳定的目的。而灯丝电源处在IMV左右的高压端，为此设计了光路传输系统，把高压端与低压端隔离开，同时又能传输控制信号。用一台可编程序控制器（PLC）作为主要控制硬件完成控制任务，同时编写了PLC控制软件。对于能量稳定系统，介绍了其工作原理、外部硬件组成（包括另一台PLC站）。针对能量稳定系统的特殊要求，在软件方面设计两种工作模式：变频器稳定模式和加速器调试和维修使用。以上两个控制站都有完备的报菟显示功能。使用组态王5.0开发了上位机（工控机）的动态显示画面，它能完成计算机控制命令的发布、参数显示和随机修改控制参数等功能。实验表明以上工作都达到设计要求，效果良好。

基于PLC的电子加速器安全控制系统

本文主要介绍了我在中科院近物所电子辐照室所研制的大功率电子加速器计算机控制系统方面的工作。文章在简要介绍了加速器的研制背景，该加速器的结构特点和工作原理后，主要叙述了基于可编程控制器（PLC）的加速器计算机控制系统的设计思想、硬件设备的特点和软件系统的组成。集散型计算机控制系统（DCS）硬件和软件的设计内容以及所能实现的控制功能是本文的重点。经过全组人员的共同努力，计算机控制系统已投入使用。并于2000年11月成功地调试出束流。从目前情况来看，加速器计算机控制系统运行正常，取得了满意的效果。

大功率电子加速器的预研与束流传输的研究

电子束辐照烟道气脱除502和NOx技术是一项将辐射物理和辐射化学紧密结合的高新技术。该项技术自1970年被提出后，经历了20多年的逐步发展，已进入了工业装置阶段。目前，在美国、德国、日本、波兰和我国的成都热电厂等处建立了中试厂和工业示范厂。当前在国际上，对一该项目的关键部件电子加速器有两种方案：即日新公司的高压变压器方案和以俄罗斯新西伯利亚核物理研究所的ElV型加速器为代表的谐振变压器型。根据目前国内的实际状况和满足我所及在兰州各研究所的物理实验的需要，中利4院近代物理所在已有技术力量的基础上，并在国家计委的大力支持下，立项研制大功率谐振变压器型电子加速器。这篇论文首先对1.5Mev/300mA三相谐振变压器型电子加速器的高压电极表面电场强度、分布电容、电感、三相谐振频率等作了预研。在此基础上，着重对强流静电加速管轴上电位和电场分布、平面电子枪的实际电流密度、电极膜孔透镜对束流的聚焦性能、加速管中电子轨迹和出射斜率、球面阴极的电子光学特性等作了详细的计算和分析，从计算得到的结果来看，所设计的电场能够满足束流传输的要求。另外，还对加速管非均匀场对电子负载的抑制作用，离子反轰阴极作了初步研究。论文的另一个重点是研究了静电加速管中强流电子束的空间电荷效应。根据实际情况，合理地建立了物理模型。并对模型上的4个不同位置的束内外径向电位分布、空间电荷对轴＿L电位的影响，以及空间电荷力对束流传输的影响等进行了详尽的理论计算和分析。在对轴上电场分布进行分析时，发现可以将电场沿轴向分为3个区域，并认真对每个区域的作用作了详细的分析说明。特别指出了，强流静电加速管的设计关键在加速管的前端，与弱流加速管相比，前者的变化幅度要大得多。论文最后对大功率电子加速器部件的加工和三相谐振变压器高压发生器模拟实验结果给予了介绍和分析。

用于加速器控制的神经元网络的研究与设计

随着HIRFL-CSR工程的进展，前端控制系统的改造在实时性、可靠性和成本等方面提出了更高的要求。而且HIRFL-CSR系统工作坏境非常复杂，各种干扰难以预测，使用传统方法很难达到稳定的控制效果。针对这些问题，本论文利用LonWorks现场总线技术与智能控制相结合的方法，研究和设计了用于HIRFL-CSR端控制的神经元网络系统。本文首先阐述了智能控制的产生与发展，分析了智能控制的结构理论和智能控制的主要技术，深入研究了神经网络算法及一些典型的用于控制的神经元网络模型。并从HIRFL-CSR控制角度出发，设计了用于加速器控制的神经网络控制模型，该神经网络利用一种全局寻优的自适应快速即算法来弥补基本B尸算法的缺陷，使其更加符合HIRFL-CSR控制系统的要求。其次，结合HIRFI-CSR工程的控制要求，采用Lonworks现场总线技术，把传统的集中与分散相结合的集散控制结构，变成新型的全分布式结构，把控制功能、彻底下放到现场，依靠现场智能设备本身实现基本控制功能，形成一个低成本，高可靠性的前端现场智能控制系统。采用神经元芯片实现了智能控制器和网络适配器，结合神经网络控制技术设计和实现了HIRFL-CSR控制网络的试验平台。该神经元网络的整体构架符合现代控制技术的网络化，智能化，分散化和开放化的发展趋势。最后，总结了神经元网络的研究与设计，并提出神多兄网络柞加谏器智能神不课题对HIRFL-CSR控制的完瞥迸行了有益的探索，提出了可行的实现方案，该研究对于HIRFL-CSR控制系给的改造具有重要的工程意义。