Study of a magnetic alloy-loaded RF cavity for bunch compression at the CSR

The Heavy Ion Research Facility and Cooling Storage Ring (HIRFL-CSR) accelerator in Lanzhou offers a unique possibility for the generation of high density and short pulse heavy ion beams by non-adiabatic bunch compression longitudinally, which is implemented by a fast jump of the RF-voltage amplitude. For this purpose, an RF cavity with high electric field gradient loaded with Magnetic Alloy cores has been developed. The results show that the resonant frequency range of the single-gap RF cavity is from 1.13 MHz to 1.42 MHz, and a maximum RF voltage of 40 kV with a total length of 100 cm can be obtained, which can be used to compress heavy ion beams of U-238(72+) with 250 MeV/u from the initial bunch length of 200 ns to 50 ns with the coaction of the two single-gap RF cavity mentioned above.

Dissociative recombination of the acetaldehyde cation, CH3CHO+

The dissociative recombination of the acetaldehyde cation, CH3CHO+, has been investigated at the heavy ion storage ring CRYRING at the Manne Siegbahn Laboratory in Stockholm, Sweden. The dependence of the absolute cross section of the reaction on the relative kinetic energy has been determined and a thermal rate coefficient of k(T) = (1.5 +/- 0.2) x 10(-6) (T/300)(-0.70 +/- 0.02) cm(3) s(-1) has been deduced, which is valid for electron temperatures between similar to 10 and 1000 K. The branching fractions of the reaction were studied at similar to 0 eV relative kinetic energy and we found that breaking one of the bonds between two of the heavy atoms occurs in 72 +/- 2% of the reactions. In the remaining events the three heavy atoms stay in the same product fragment. While the branching fractions are fairly similar to the results from an earlier investigation into the dissociative recombination of the fully deuterated acetaldehyde cation, CD3CDO+, the thermal rate coefficient is somewhat larger for CH3CHO+. Astrochemical implications of the results are discussed.

Nuclear physics program at HIRFL

With the commissioning of HIRFL-CSR, HIRFL can provide heavy ion beams with energy covering the range of several MeV/u to 1 GeV/u. In this talk, the experiments on nuclear physics at different energies to be carried out with different experimental setups at HIRFL will be introduced.

TRITON-(HE)-H-3 RELATIVE AND DIFFERENTIAL FLOWS AND THE HIGH DENSITY BEHAVIOR OF NUCLEAR SYMMETRY ENERGY

Using a transport model coupled with a phase-space coalescence after-burner we study the triton-He-3 relative and differential transverse flows in semi-central Sn-132 + Sn-124 reactions at a beam energy of 400 MeV/nucleon. We find that the triton-He-3 pairs carry interesting information about the density dependence of the nuclear symmetry energy. The t-He-3 relative flow can be used as a particularly powerful probe of the high-density behavior of the nuclear symmetry energy.

CONSTRAINTS ON THE DENSITY DEPENDENCE OF THE SYMMETRY ENERGY

Collisions involving Sn-112 and Sn-124 nuclei have been calculated with the ImQMD transport model in order to place constraints on the density dependences of the nuclear symmetry energy. Consistent constraints on the symmetry energy at sub-saturation density have been obtained by comparing these transport calculations to measurements of isospin diffusion and to the ratios of neutron and proton spectra. New isospin diffusion results from E/A = 35 MeV are also presented.

Some Superconducting Magnets at IMP

Some superconducting magnets research at IMP (Institute of Modern Physics, CAS, Lanzhou) will be described in this paper. Firstly, a superconducting electron cyclotron resonance ion source (SECRAL) was successfully built to produce intense beams of highly charged heavy ions for Heavy Ion Research Facility in Lanzhou (HIRFL). An innovation design of SECRAL is that the three axial solenoid coils are located inside of a sextupole bore in order to reduce the interaction forces between the sextupole coils and the solenoid coils. For 28 GHz operation, the magnet assembly can produce peak mirror fields on axis of 3.6 T at injection, 2.2 T at extraction, and a radial sextupole field of 2.0 T at plasma chamber wall. Some excellent results of ion beam intensity have been produced and SECRAL has been put into operation to provide highly charged ion beams for HIRFL since May 2007. Secondly, a super-ferric dipole prototype of FAIR Super-FRS is being built by FCG (FAIR China Group) in cooperation with GSI. Its superconducting coils and cryostat is made and tested in the Institute of Plasma Physics (IPP, Hefei), and it more 50 tons laminated yoke was made in IMP. This super-ferric dipole static magnetic field was measured in IMP, it reach to the design requirement, ramping field and other tests will be done in the future. Thirdly, a 3 T superconducting homogenous magnetic field solenoid with a 70 mm warm bore has been developed to calibrate Hall sensor, some testing results is reported. And a penning trap system called LPT (Lanzhou Penning Trap) is now being developed for precise mass measurements.

DISSOCIATIVE RECOMBINATION OF PROTONATED PROPIONITRILE, CH3CH2CNH+: IMPLICATIONS FOR TITAN'S UPPER ATMOSPHERE

The dissociative recombination of protonated propionitrile, CH3CH2CNH+, has been investigated at the heavy ion storage ring, CRYRING, at the Manne Siegbahn Laboratory, Stockholm University, Sweden. The thermal rate coefficient has been deduced to follow k(T) = (1.5 +/- 0.2) x 10(-6) (T/300)(-0.76) (+/-) (0.02) cm(3) s(-1) for electron temperatures ranging from similar to 10 to similar to 1000 K. Measurements of the branching fractions were performed at similar to 0 eV relative kinetic energy. It has been found that in 43% +/- 2% of the reactions the four heavy atoms remain in the same product fragment. An equal portion of the reactions leads to products where one of the heavy atoms is split off from the other three and 14% +/- 1% result in a breakup into two heavy fragments containing two heavy atoms each. We discuss the significance of the data to Titan's upper atmosphere.

Experimental studies of the dissociative recombination of CD3CDOD+ and CH3CH2OH2+

Aims. We determine branching fractions, cross sections and thermal rate constants for the dissociative recombination of CD3CDOD+ and CH3CH2OH2+ at the low relative kinetic energies encountered in the interstellar medium. Methods. The experiments were carried out by merging an ion and electron beam at the heavy ion storage ring CRYRING, Stockholm, Sweden. Results. Break-up of the CCO structure into three heavy fragments is not found for either of the ions. Instead the CCO structure is retained in 23 +/- 3% of the DR reactions of CD3CDOD+ and 7 +/- 3% in the DR of CH3CH2OH2+, whereas rupture into two heavy fragments occurs in 77 +/- 3% and 93 +/- 3% of the DR events of the respective ions. The measured cross sections were fitted between 1-200 meV yielding the following thermal rate constants and cross-section dependencies on the relative kinetic energy: sigma(E-cm[eV]) = 1.7 +/- 0.3 x 10(-15)(Ecm[eV])(-1.23 +/- 0.02) cm(2) and k(T) = 1.9 +/- 0.4 x 10(-6)(T/300)-0.73 +/- 0.02 cm(3) s(-1) for CH3CH2OH2+ as well as k(T) = 1.1 +/- 0.4 x 10(-6)(T/300)(-0.74 +/- 0.05) cm(3) s(-1) and s(Ecm[eV]) = 9.2 +/- 4 x 10(-16)(Ecm[eV])-1.24 +/- 0.05 cm(2) for CD3CDOD+

重离子束辐照对植物组织培养及转基因操作的影响

目的：建立重离子束辐照结合植物组织培养技术进行植物诱变的新方法，使用该方法率先开展植物组织细胞的传能线密度（LET）生物学效应的研究，尝试重离子束辐照结合农杆菌转染及质粒微注射法转基因操作。 材料与方法：采用兰州重离子研究装置(HIRFL)加速的碳离子束辐照非洲紫罗兰、丽格海棠、新几内亚凤仙以及紫花苜蓿的外植体，测定形态学指标，计算不同外植体的相对生物学效应（RBE）。以非洲紫罗兰叶片外植体为对象研究RBE随LET的变化关系。使用氖离子束辐照烟草叶片外植体结合农杆菌转染方法进行赤霉素4（GA4）基因转染实验；使用碳离子束辐照苜蓿愈伤组织结合质粒微注射方法进行β－葡萄糖苷酸酶（GUS）基因转染实验。 结果： 1. 不同剂量的936MeV的碳离子束和8MV的X射线辐照三种花卉及一种牧草的外植体后，基于存活率的RBE值分别为2.3、1.6、2.1和4.0； 2. LET值在31~151keV/μm区间的碳离子束辐照非洲紫罗兰叶片外植体。基于鲜重增殖（FWI）的RBE值随LET的增加而增加，151keV/μm时达到最高值6.7； 3. 烟草离体叶片外植体经过5Gy的1600MeV氖离子束辐照后进行农杆菌转基因操作，最终获得转染率为3.9%，单纯农杆菌转基因的转染效率为3.2%； 4. 20Gy的936MeV的碳离子束辐照苜蓿愈伤组织后结合组织表面pBI121质粒溶液微量注射处理后，获得GUS基因瞬间表达效率高达84.6%。 结论： 1. 不同花卉植物组织培养用外植体的辐照敏感性不同，本研究发现丽格海棠的辐射敏感性最高，其次是新几内亚凤仙，非洲紫罗兰的最不敏感； 2. 不同花卉植物外植体经离子束辐照诱变处理后，得到的再生植株突变类型不尽相同，主要包括叶的突变和茎的突变； 3. RBE的随LET的增大而增加可以归因于离子在生物体中能量沉积的增加，研究发现各生物学终止点受到损伤或者抑制的程度基本上是随着LET的增大而增大； 4. 通过离子束辐照结合植物组织培养方法最终获得了非洲紫罗兰叶绿素缺失突变体，该突变体通过植物组织培养技术能够稳定遗传； 5. 中能氖离子束辐照能够略微提高烟草农杆菌转基因的转化效率，辐照能够使再生植株花期提前； 6. 中能碳离子束辐照结合苜蓿愈伤组织表面微量注射质粒溶液法进行转基因操作能获得更高的基因转染效率

深层治癌束运线极高、超高真空系统

本论文根据已有的设计方案及图纸，验证设计方案的可行性。主要内容如下：第一，根据公式估算深层治癌束运线各段的真空度，并用VAKTRAK程序模拟出压力分布曲线；第二，运用ANSYS程序对烘烤段各真空管道，尤其是盒形真空室（二极铁真空室）进行力学分析，验证设计尺寸是否可行；第三，根据力学分析，确定超薄壁拱形真空管道的波宽和波高，能够满足使用要求。第四，参考德国GSI有关资料，对膜窗材料进行了计算和验证，并成功的运用到实际中去。 目前，深层治癌束运线真空系统已经安装完毕，经过抽空、检漏，各元件均已达到设计要求，非烘烤段的真空度已达标，烘烤段已达到烘烤前应有的真空度，现正在安装烘烤外套及烘烤控制装置

CSR真空控制系统的研究

本论文主要解决CSR真空系统的控制实现与连锁保护问题。 HIRFL-CSR（Heavy Ion Research Facility at LanZhou-Cooling Storage Ring兰州重离子冷却储存环）是国家重大科学工程。为了保证CSR正常运行，超高真空系统的平均真空度必须达到6×10-9Pa，超高的真空度来之不易，CSR上任何一处真空设备发生故障，就会破坏真空度，所以CSR必须具有响应速度快、安全可靠，稳定性好的真空控制与连锁保护系统。 HIRFL-CSR真空设备有离子泵电源、分子泵、钛升华泵、阀门、真空计等。分子泵只在粗抽时使用，钛升华泵为间歇升华，因此不需要监控。需要显示和控制的设备为离子泵电源、真空计和真空阀门。通过对CSR上每个真空计的真空度数据的监测和真空阀门状态的采集，一旦真空度降低到一定阈值，立即关闭相应位置阀门（保护真空）,并给出故障报警，从而实现真空系统的连锁保护。 真空控制系统以嵌入式处理器ARM、复杂可编程逻辑器件CPLD和微控制器MSP430为核心，实现了远程数据采集、数据显示和自动控制等功能。本系统可以进行现场监控与调试，也可以通过集成的100Mbps以太网接口电路进行远程监测与控制，CSR上各处真空度和真空阀门状态自动传送到中央控制中心，中控中心也可以发送命令查询当前真空设备状态和各种读数。 本文主要介绍了基于ARM、CPLD和MSP430的嵌入式真空控制系统的设计与实现。内容主要包括(1)系统各部分硬件电路设计与真空控制功能实现 ，硬件系统调试 。(2)嵌入式uClinux操作系统构建和在其上进行的应用程序，设备驱动程序，串行通信程序的开发。（3）CPLD的VHDL程序和MSP430的C430程序设计。 本文目的是解决CSR真空控制系统问题，但对于许多远程数据采集与控制等问题的解决有重要参考价值

CSRm高频系统控制器

HIRFL-CSR（Heavy Ion Research Facility at LanZhou-Cooling Storage Ring兰州重离子冷却储存环）是国家重大科学工程，其控制系统是一个庞大的系统，由许多分控制系统组成，高频系统是其重要组成部分之一。加速器的加速过程都是由高频系统来完成的。由于高频控制系统的控制对象就是高频腔体，控制系统的稳定性和输出频率的精确性将直接影响到加速器系统的正常工作，而对于高频系统的状态回读又直接决定了对于高频系统的远程监控能力，所以高频控制系统的设计非常重要。本设计基于现场可编程逻辑门阵列FPGA和数字信号专用处理器DSP搭建， 一方面可以完成从控制中心远程控制高频腔体，另一方面也可以完成对于当前状态的读取，所经过的通道也是多样化的，包括CPCI总线通信，CANBUS总线通信或者是485总线通信。本文的内容包括了1>对于高频控制系统控制对象的分析以及各种控制参数要求。2>组成此系统的硬件部分分析选择以及硬件系统的搭建过程。3>对FPGA和DSP进行程序设计的过程和方法。本文的价值不仅在于对高频系统的控制上，对于其他数据采集系统，远程控制系统以及总线通信和数据分析算法上也有着参考价值

CSR电源调节器硬件平台设计

HIRFL-CSR（Heavy Ion Research Facility at LanZhou-Cooling Storage Ring兰州重离子冷却储存环）是国家重大科学工程，其控制系统是一个庞大的系统，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。加速器运行的所有过程都为电源所控制，所以我们的控制系统的直接控制对象就是磁场电源。为了保证CSR正常运行，控制过程波形的跟踪精度、速度和稳定度，是数字电源调节器的关键所在。电源控制系统以嵌入式处理器ARM、现场可编程门阵列FPGA为核心，实现了远程数据采集、网络通讯和自动控制等功能。本系统可以进行现场监控与调试，也可以通过集成的100Mbps以太网接口电路进行远程监测与控制，CSR上各处输出电压值和电源运行状态自动传送到中央控制中心，中控中心也可以发送命令查询当前电源设备状态和各种读数。本文主要介绍了基于ARM和FPGA的嵌入式电源控制系统的设计与实现。内容主要包括：(1)系统各部分硬件电路设计与电源控制功能实现 ，硬件系统调试 。(2)装载嵌入式Linux操作系统，测试平台接口信号，通过FPGA生成多路数字PWM波形。本文目的是解决CSR电源控制系统问题，但对于许多远程数据采集与控制等问题的解决有重要参考价值

电荷测量与时序逻辑电路的研究

中国科学院近代物理研究所大科学工程HIRFL-CSR（Heavy Ion Research Facility at LanZhou-Cooling Storage Ring兰州重离子冷却储存环）已建成并处于调试和验收阶段，实验探测系统也正在建设当中。CSRm实验探测系统由外靶系统和内靶系统构成，主要用于核物理实验研究。CSRm TOF测量系统是现阶段CSRm实验探测系统的主要任务之一。 针对CSRm TOF测量系统电荷测量部分，论文阐述了一种采用前端ASIC-SFE16（Saclay Front End 16）芯片实现电荷测量的新型方法。它替代了采用分立元件和电子学插件构建系统的传统方法，着重解决了近代核物理实验中越来越突出的多路多道需求和高性能指标要求。根据我所多丝漂移室探测器的实际情况，我们设计了基于ASIC芯片的电荷测量前端电路板，结合中国科技大学的时间测量数字获取板，我们初步完成了对系统软硬件的测试，给出的实验室性能测试指标，为其在实验探测系统中的应用奠定了坚实的基础。 同时为了选出测量中的有用事例，需要进行事例判选，因此我们研制了多路延迟/脉宽调节时序逻辑电路，主要功能是针对提供的多路逻辑时序信号进行延迟和脉宽调节，支持NIM负信号输入和输出。 文中最后一部分论述了根据在调试过程中出现的实际问题所提出的解决方法，主要是针对电路的可靠性设计和噪声的处理

重离子治癌装置的束流位置控制系统

近代物理所依托兰州重离子冷却储存环（HIRFL-CSR）开展重离子治癌研究。在重离子治癌过程中，需要对束流位置十分精确的控制。本文实现了精确控制重离子束对肿瘤实现三维适形扫描。 对肿瘤切片方向定位采用主动磁扫描方式，通过控制X、Y 扫描铁电源实现束流对肿瘤一层切片中各点的扫描，在治疗过程中需要实现位置变化与辐照剂量的联动。为满足束流位置切换时扫描铁电源的阶跃响应过程，采用了一种新的加速器电源控制方式，通过控制频率变化实现扫描铁电源阶跃响应过程。该方法具有精度高、参数少、响应速度快和实时性好的特点。本文提出了扫描铁电源电压控制的数学模型和实现结构，通过FPGA+DSP+DDS的硬件平台实现该电源控制方法。最终完成了对扫描铁电源高精度的控制。 肿瘤深度方向定位实质上是重离子束流Bragg峰的定位。Bragg峰与束流能量的关系要求重离子束在不同能量间切换，因而需要加速器实现变能加速。本文设计完成了适应变能加速的高频控制器，介绍了高频控制器实现方法，从而满足不同深度肿瘤切片对束流能量的要求。 核心及创新点：(1)实现重离子治癌过程中束流位置和剂量的联动; (2)基于频率调节的扫描铁电源控制器; (3)满足变能加速的高频控制器 从现场的测试和应用结果表明位置控制系统达到了设计要求