Institutional Repository of Institute of Modern Physics, CAS
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Dynamic Measurement System for Dipoles of RCS for CS
No full textA dynamic measurement system was developed by the Institute of Modern Physics (IMP) for the dipole prototype of Rapid Cycle Synchrotron (RCS) of China Spallation Neutron Source (CSNS). The repetition frequency of RCS is 25 Hz. The probe is a moving arc searching-coil, and the data acquisition system is based on the dynamic analysis modular of National Instrument. To get the error of high order harmonics of the field at basic frequency, the hardware integrator is replaced by a high speed ADC with software filter and integrator. A series of harmonic coefficients of field are used to express the varieties of dynamic fields in space and time simultaneously. The measurement system has been tested in Institute of High Energy Physics (IHEP), and the property of the dipole prototype of RCS has been measured. Some measurement results and the repeatability of system are illustrated in this paper
Structural stability of C-60 films under the bombardment of 1.95 GeV Kr ions
No full textThe structural stability of C-60 films under the bombardment of 1.95 GeV Kr ions is investigated. The irradiated C-60 films were analyzed by Fourier Transform Infrared (FTIR) spectroscopy and Raman scattering technique. The analytical results indicate that the irradiation induced a decrease of icosahedral symmetry of C-60 molecule and damage of C-60 films; different vibration modes of C-60 molecule have different irradiation sensitivities; the mean efficient damage radius obtained from experimental data is about 1.47 nm, which is in good agreement with thermal spike model prediction
Properties of β-Delayed Proton Emission in Neutron-Deficien Rare-Earth Isotopes
No full text基于兰州重离子加速器国家实验室的 SFC 加速器，通过 58Ni+92Mo、
40Ca+92Mo 和 40Ca+106Cd 熔合蒸发反应，产生了稀土区缺中子β延发质子发射先
驱核。使用氦喷嘴带传输系统将反应产物收集并传输到低本底测量区域，利用
p-γ(X)-γ(X)以及 p-γ-t符合测量，鉴别了β延发质子发射先驱核，获得了延发质子
谱，提取了先驱核的寿命，得到以下物理结果：
(1) 首次观测到146Ho β延发质子衰变至孙子核145Tb激发态的γ跃迁， 提取了
延发质子衰变到孙子核各激发态的相对分支比，结合前人的实验成果，建议了
146Ho 基态的自旋宇称。
(2) 通过分析与延发质子符合的γ跃迁，发现145,147Er 的 1/2+基态和 11/2-同核
异能态均具有延发质子衰变性质，拟合孙子核 144,146Dy 4+→2+跃迁的衰变曲线，
获得了 145,147Er 中 11/2-同核异能态的半衰期。
(3) 重新分析了129Nd β延发质子衰变性质， 结合已有 129Nd EC+β+衰变数据，
指出129Nd中可能存在一个寿命较长的同核异能态。
(4) 与已有实验相比，设置了不同的带传输时间，重新研究了143Dy β延发质
子衰变，得到了与前人不同的相对分支比，建议了 143Dy基态的半衰期
miR-185 regulated DNA-damage response through targeting ATR gene
No full textDNA是生命的信息、遗传中心，同时也是电离辐射的关键靶，维持DNA序列、结构的完整性和遗传稳定性，是细胞的中心事件，并形成 ATM、ATR 为核心的 DNA 辐射损伤监控和应激网络。microRNA（miRNA）是一类新的调控因子，其表达的时空特异性、调控方式的多样性和灵活性，使其成为信使 RNA 强有力的调节子。miRNA层面上研究 DNA辐射损伤修复调控机理，将丰富DNA辐射损伤修复理论，具有重大的理论和应用价值。该方面的研究刚起步，有很多未知领域等待探索。 通过对辐照后临床组织样本的 miRNA 芯片数据分析，发现辐照后 miR-185 的表达显著下降；通过荧光定量 PCR 检验，发现辐照后组织和细胞系中 miR-185 的下调表达具有普遍性；通过 miRanda、RNA22 等靶基因预测软件分析，确定 ATR 为 miR-185 调控的潜在靶基因；通过 Western blot、qRT-PCR 实验，证明 miR-185 抑制 ATR 基因的表达；从而显著性地提高了细胞的辐射敏感性（凋亡比率升高，克隆存活率下降），并检测到 miR-185 可以直接抑制移植瘤的生长。 ATR是 DNA辐射损伤修复关键蛋白激酶，本课题首次发现 miR-185 通过抑制 ATR基因的表达， 调控 DNA 辐射损伤修复。该结果的发现，一方面在 miRNA 层面上丰富了 DNA 辐射损伤修复调控机制，另一方面为 miR-185在肿瘤诊断、放疗靶点、放疗联合基因治疗等方面的潜在应用，奠定了理论基础
IC Design for digital regulator based on the state-space equation solver
No full text兰州重离子冷却储存环是国家重大科学工程，磁场电源系统是 CSR 控制系统中重要
的一部分。本论文即在 CSR 数字化改造工程的背景下，以过程控制器为基础，提出的具
有目前控制领域前沿性，能满足 5 阶及其以下各阶，以极点配置和状态空间方程设计方
法为基础的新一代数字调节控制器。
此新一代数字调节控制器是由用于获取满足用户需求参数的测试与用户系统，用于
实现数字调节器算法的硬件编程和用于对数字调节器参数进行实时管理和给定置入的
上位机软件系统三部分组成。本文主要就此调节器的系统模型优化与仿真，测试与用户
系统和硬件编程部分进行了详细阐述。
核心及创新点： （1）采用了新一代的先进 FPGA+ARM 硬件平台； （2）实现了状态空
间方程直接硬件解算，完成了数字调节器的IC设计； （3）研发了高速、实时的24 位浮
点数运算单元和采用了实时流水线技术的矩阵数学解算； （4）实现了对 5阶及以下各阶
单输入单输出高速高稳定系统的控制。
从测试和应用结果来看，该数字调节控制器系统已经达到了设计要
重离子治癌同步加速器束流累积的方法及其装置
No full text本发明主要涉及一种提高重离子束治癌同步加速器中离子数目的束流累积方法和装置。一种重离子治癌同步加速器中束流累积的方法，有如下步骤：1.将注入器提供的离子束注入到同步加速器中；2.在电子冷却装置内，产生与被冷却离子束流具有相同平均速度的电子束；3.将电子束偏转到同步加速器环上的一个冷却段；4.离子通过冷却段，与电子发生相互碰撞作用，冷却重离子束；5.将作用后的电子偏转出去。本发明还提供一种装置，在同步加速器的直线段的上游中依次设有四级磁铁、补偿螺旋管，在补偿螺旋管的上游及下游设有校正磁铁；在同步加速器的直线段的下游与上游设置相同且对应设置；在同步加速器的直线段中段设置有束流冷却装置。本发明的优点是提供的离子数目显著提高。离子束发射度和动量分散缩小，束流品质提高，束流寿命增长
CURRENT STATUS AND FUTURE PROJECTS OF THE ITHEMBA LABS
No full textThe cyclotron facilities at iThemba LABS have been<br />utilized for isotope production, nuclear physics research,<br />proton therapy and neutron therapy for nearly 25 years.<br />The upgrading and replacing of redundant systems is<br />essential, in order to keep the interruptions due to<br />equipment failure to a minimum. The computer control<br />system will be replaced by an Experimental Physics and<br />Industrial Control System (EPICS) and the analogue lowlevel<br />RF control systems will be replaced with digital<br />systems. The Minimafios ECR ion source is being<br />replaced with an ECR source that was used at the former<br />Hahn Meitner Institute. Another source, based on the<br />design of the Grenoble test source, will be commissioned<br />later this year. To increase the production of radioisotopes,<br />the 66 MeV proton beam is split with an electrostatic<br />channel to deliver two beams simultaneously. The first<br />results with the beam splitter will be reported. A phase<br />measuring system for the separated-sector cyclotron,<br />comprising 21 fixed probes, has been installed. The<br />progress of these projects and the status of the facilities<br />will be presented. Plans for new facilities for proton<br />therapy and radioactive beams will also be discussed
STATUS OF THE LBNL 88-INCH CYCLOTRON HIGH-VOLTAGE
No full textThe goal of the project is to design and install a new<br />center region that allows external beam injection at<br />voltages between 20 and 30 kV for high intensity beams.<br />This new center region will make use of a spiral inflector<br />to eliminate the use of a gridded mirror for high intensity<br />beams. At the same time the mechanical design must be<br />flexible enough to allow use of the existing center region<br />for less intense beams. The use of two or more different<br />center regions is necessary to cover the wide range of<br />operation parameter space utilized by the 88-Inch<br />Cyclotron nuclear science and applied research programs.<br />The project also includes HV upgrades to the external<br />injection lines and HV insulation of the AECR and<br />VENUS sources with the goal to provide focusing for<br />beams up to 25 kV or if feasible up to 30 kV. The current<br />spiral inflector design is based on extensive 3D FEM<br />simulations for which results will be presented. In<br />addition results from ongoing efforts to improve on the<br />transport efficiency from the AECR ion source to the<br />current mirror inflector will be discusse
PROGRESS TOWARDS HIGH INTENSITY HEAVY ION BEAMS AT THE
No full textThe AGOR-facility has an on-going upgrade program<br />aiming at intensities beyond 1012 pps for heavy ion beams<br />up to Pb. The main elements of the program are: further<br />development of the ECR-source, improvement of the<br />transmission into and through the cyclotron, and<br />protection of equipment against excessive beam loss.<br />Further improvement of the ECR ion source is facilitated<br />by the installation of a second source. Redesign of the<br />Low Energy Beam-line, to compensate for aberrations, is<br />in progress; simulations predict a significant increase in<br />transmission. A new, cooled, electrostatic extractor is<br />being commissioned and the beam loss control system has<br />been completed. The main remaining issue is vacuum<br />degradation induced by beam loss caused by charge<br />exchange on the residual gas. Tracking calculations of the<br />distribution of the beam losses over the vacuum chamber<br />to determine the optimum location of scrapers are<br />underway. A gold coating was recently applied to relevant<br />parts of the vacuum chamber aiming at reduction of beam<br />loss induced desorption
CYCLOTRON VACUUM MODEL AND H- GAS STRIPPING LOSS
No full textA model to compute the vacuum in the different parts
of IBA H- cyclotrons has been developed. The pressure
results are then used to compute the beam transmission
through the cyclotron by integration of the residual gas
stripping cross-section along the ion orbits. The model
has been applied to the ARRONAX Cyclone®70 with the
initial vacuum design and the results are compared to the
experimental data. The pressure and the transmission are
in good agreement with experimental data.IMP;Chinese Academy of Science