Characteristics of a 4-fold segmented clover detectore

Four high-purity germanium 4-fold segmented Clover detectors have been applied in the experiment of neutron-rich nucleus 21N. The performance of those four Clovers have been tested with radioactive sources and in-beam experiments, and the main results including energy resolution, peak-to-total ratios, the variation of the hit pattern distribution in different crystals of one Clover detector with the energy of γ ray, and absolute full energy peak detection effciency curve, were presented.     

Commissioning of electron cooling in CSRm

A new generation electron cooler has started operation in the heavy ion synchrotron CSRm which is used to increase the intensity of heavy ions. Transverse cooling of the ion beam after horizontal multi-turn injection allows beam accumulation at the injection energy. After optimization of the accumulation process an intensity increase in a synchrotron pulse by more than one order of magnitude has been achieved. In given accumulation time interval of 10 seconds, 10⁸ particles have been accumulated and accelerated to the final energy. The momentum spread after accumulation and acceleration in the 10^－4 range has been demonstrated in six species of ion beams. Primary measurements of accumulation process varying with electron energy, electron beam current, electron beam profile, expansion factor and injection interval have been performed. The lifetimes of ion beams in the presence of electron beams were roughly measured with the help of DCCT signal.     

Studies of timing properties for a TOF counter at an external target facility

Timing and amplitude properties of a prototype scintillator TOF counter at an external target facility are studied with a cosmic rays test. The dependence of signal pulse height and time resolution on the coordinate along the scintillator TOF counter is investigated with two different discriminators. A time resolution of 165 ps can be achieved at the center of the counter with a constant fraction discriminator. Time resolution better than 150 ps is obtained at the center with a leading edge discriminator after time wall（ correction is applied for off-line analysis.     

超重核研究实验方法的历史和现状简介

简单介绍了超重核合成的历史,详细讨论了目前超重核合成最成功的技术路线,包括产生方法、分离手段以及探测技术,并就各种技术的优缺点进行了比较.探讨了目前超重核研究所面临的困难以及介绍了国际上几个主要相关实验室的研究动态,并对超重核研究的发展趋势做了简单展望. The history of the synthesis of the transuranium nuclei is briefly introduced. The most successful techniques currently used for synthesizing super heavy nuclei are surveyed and discussed in detail. The drawbacks and the problems for reaching the stability island of super heavy nuclei with the techniques currently used are discussed. The present status and perspectives of the super heavy nuclei research at different laboratories are also introduced. Finally, a brief prospect on the trends...     

最小发散级数和最大收敛级数不存在理论及其论证

无穷级数是高等数学中的一部分重要内容.在判断无穷级数收敛或发散时,比较原理(比较审敛法或比较判别法)是一个有效的判别法,其基本原理是:     

兰州放射性束流线上速度选择器的设计制造及初步调试

描述了一台在兰州放射性次级束流线(RIBLL)前端安装的速度选择器系统, 该系统由2个三组合四极透镜组和1个正交的电磁场组成, 将用于熔合蒸发余核的研究. 介绍了该设备的设计思路、基本参数和本底抑制能力、传输效率、角度接收度以及动量接收度的测量结果. 结果表明该系统达到设计要求, 进行适当改造后可用于Z≤110的超重核素的研究和中重核区滴线核的研究.     

模拟测试交换格式的研究与实现

为提高自动测试系统对模拟电路故障诊断的效率和水平,研究定义一种模拟电路测试交换机制,为基于模拟仿真测试程序集(TPS)开发和数据的传递提供信息和数据格式;通过Spice对电路进行仿真,将仿真数据进行小波分析提取特征,并由BPN、SVM、AIS进行知识生成与评价,最终实现ATIF文件自动生成;实验将ATIF文件解析导入到后处理环境中由测试程序执行检测故障,验证了测试格式的有效性。     

基于IEEE1232的模拟电路TPS自动生成系统开发

目前在模拟电路故障诊断及测试过程中存在两个问题：测试信号的连续性及容差特性造成的测试信号数量巨大,故障知识表示复杂,测试程序（Test Program,简称TP）的编写多用基于决策知识的人工生成方法。通过对IEEE1232标准的体系结构和诊断推理机要求的分析,论文对IEEEE1232模型体系进行扩充,提出一种包含特征提取技术和多种AI诊断方法的诊断知识库生成协议,设计并实现了符合1232标准知识库的TPS自动生成测试系统。提高了诊断知识的移植性,实现了TPS的自动生成。仿真结果证明了该方案的可行性     

用于重离子治癌回旋引出的实时流强测量系统北大核心CSCD

为满足重离子治癌加速器装置(HIMM)回旋加速器引出段束流流强的测量需求,设计了新的束流流强测量系统,该系统利用积分电流变换器(ICT)及锁相放大器等配套电子学,能够实现束流流强的非拦截实时测量。文中首先分析了中能束线(MEBT)束流流强的测量需求,并对设计方案进行了实验室系统分析和在线束流强测量。实验室结果表明,锁相放大器的幅度和相位响应一致性满足测量需求。由于ICT对束流流强的测量是相对测量,先使用法拉第筒对ICT进行在线标定;标定前先对法拉第筒(FC)(20μA档位)和ICT系统的流强分辨在线测量,分别为6.45 nA和5.163 nA。由于束流抖动的影响,测量的束流的稳定性约90 nA,其对应的相对测量误差约8%,ICT系统响应时间小于1 ms。测量结果表明,该系统满足物理测量需求。回旋加速器高频系统参数变化引起ICT标定系数变化的工作将在进一步工作中展开。     

19F+27Al反应产物的角分布、角分散与耗散机制

完成了114MeV¹⁹F+²⁷Al深部非弹性碰撞产物的角分布测量.分析了反应产物B,C,N,O,F,Ne,Na,Mg和Al的实验室系角分布,讨论了反应形成的中间双核系统随时间演化过程中角分布所表现出的耗散特点.从实验上提取了反应产物各元素的角分散参数并作了角分散参数的理论拟合,讨论了角分散参数的物理意义以及角分散参数与耗散反应产物的电荷数Z之间的依赖关系.