CR-39核径迹探测器及其在核科学等研究领域中的应用

介绍了一种核径迹探测器ＣＲ－３９塑料的特性,这种探测器对逞电粒子非常灵敏,它还具有稳定、透明等特点,可记录ｐ、ａ粒子,裂变碎片和其他带电粒子,它是现有固体核径迹探测器中能量沉积密度探测阈最低的材料,介绍了ＣＲ－３９对带电粒子的响应,给出了各种带电粒子的ｖＴ对限定能量损失（ＲＥＬ）的响应曲线,利用ＣＲ－３９与转换屏的组合还可测定能量范围广的中子能谱,可作为方便的个人中子剂量计,介绍了ＣＲ－３９在研究     

半导体望远镜探测系统研制及其在卫星上的应用

简要介绍了由不同厚度的Au-Si面垒和Si(Li)半导体探测器组成的全耗尽带电粒子望远镜系统的制备及其性能,给出了载有该望远镜系统的风云三号卫星（FY-3A）在轨道高度约为830 km辐射区域监测2.9—100 MeV质子和0.15—5.7 MeV电子的结果。In this paper, the performances as well as the production procedure of the charged particle telescope systems consisting of Si(Au) surface barrier detector and Si(Li) detector with different thicknesses were introduced briefly. As an example, the density distributions of the protons and electrons in space detected by the telescope systems mounted on the Fengyun 3 satellite (FY 3A) were also presented.     

高纯锗探测器在近代物理实验教学科研中的应用

高纯锗(HPGe)探测器是上个世纪70年代发展起来主要用于探测?射线的实验仪器。因其具有能量分辨率高、线性范围宽、探测效率高、性能稳定等优点,被广泛应用于核辐射探测领域中。本文对HPGe的基本结构、探测原理、技术发展以及在大学近代物理实验教学科研中的应用进行了详细阐述。     

空间低能离子探测器的紫外响应测试

在空间离子探测过程中,太阳紫外光也会进入探测器产生光污染信号。为了考察它对离子探测的影响,搭建了一套模拟太阳紫外光污染的地面测试系统,并对自主研制的空间低能离子探测器原理样机进行了紫外响应测试。实验结果表明:沿水平方向进入分析器的紫外光响应可以忽略,而以一定倾斜角进入分析器的紫外光响应计数率约为102~ 103 s−1。根据测试结果,估算出探测器对太阳紫外光的抑制率约为10−8,分析了紫外光污染对探测空间低能离子如质子和 粒子的影响。对于质子,由于其通量大,紫外光的影响不大。而对于通量较小的 粒子,紫外光的影响较大,需要进一步采取有效措施进行抑制。此外,本测试系统可以推广到其它空间粒子探测器的太阳紫外光污染的地面模拟测试。In the detection of space ions, solar ultraviolet (UV) can also enter the detector and generate a noise to the signal of ions. A testing system on the ground is built to test the UV response of detector. Experiments on a home-made principle prototype of space low-energy ion detector are carried out by using this system. The results show that the response of detector to the UV entering the electrostatic analyzer along the horizontal direction can be negligible and counts of the response to the UV along a bias direction are about 102 ~103 s−1. According to the measured results, the UV suppression ratio is estimated to be about 10−8 and the inuence of solar UV on the detection of space low-energy ions such as proton and alpha particle has been analyzed. For proton, the inuence is insigni cant due to its high ux. But for the low ux alpha particle, the inuence of solar UV is noticeable and further rejection is needed. In addition, this system can also be applied to test the UV response of other space particle detectors.     

CsI(T1)+光二极管读出探测器在中能重离子核反应实验中的应用

本文报道了CsI(T1)+光二极管读出探测器在中能重离子核反应实验中的应用.研究了这种探测器与半导体探测器构成ΔE-E望远镜鉴别轻带电粒子,及利用过零时间法来鉴别轻带电粒子的实验结果.     

浅谈半导体激光器在物理实验中的应用

本就半导体激光器与氦氖激光器进行了比较,并简单论述了半导体激光在物理实验中的应用,尤其在“全息照相”中的应用。     

基于光探测器空间辐射效应的卫星光通信系统误码率特性

通过对空间辐射环境中PIN光探测器损伤机理的分析,得到了光电流与暗电流在辐照条件下的变化规律.在此基础上,建立了基于PIN光探测器空间辐射效应的卫星光通信系统误码率模型.仿真得出,辐照强度约为5×104 Gy和8×104 Gy时,50MeV质子和10MeV质子辐照条件下的系统误码率先后达到10-6;在5×105 Gy~6×105 Gy范围内,电子与Gamma射线辐照下的误码率亦达到10-6.结合系统误码率的损伤机理,进一步研究了判决阈值对误码率的影响.结果表明,辐照强度为1MGy时,判决阈值由4.3×10-7 A上升至5.5×10-7 A,能够使误码率降低近3个量级.因此,适当选取判决阈值能够有效的改善系统误码率情况.     

带电粒子在磁场中的运动轨迹图示仪

在讲解带电粒子在磁场中的运动时,经常会遇到带电粒子入射速度大小不变,但方向要改变的情况,此时的轨迹已经从静态变为动态．对空间想象能力一般的学生来讲,问题的难度已大为提高;而一般的画图难以获得动态的效果,轨迹已成为解决问题的瓶颈．根据物理教学的直观性原则,一个物理现象,无论语言描述得怎样生动,往往不如让学生看一看现象本身或现象的模拟．笔者想到了自制教具,通过教具使轨迹从静到动,模拟出动态过程,提高学生感觉的清晰度,使学生在动态中捕获信息,找到解决问题的途径,从而发现规律．     

半导体物理效应及其应用讲座第四讲光吸收跃迁效应与半导体红外探测器的应用发展

光吸收跃迁效应是半导体光电探测器的基本物理过程.文章主要介绍光吸收跃迁效应在窄禁带半导体红外探测器应用方面的研究进展.讨论窄禁带半导体带间光吸收跃迁的理论和实验.文章还介绍了本征光吸收系数的表达式及其在材料表征和确定器件截止波长方面的应用,以及它在解释近年来发现的HgCdTe光电二极管电致负荧光现象方面的应用.     

多环型半导体探测器的研制

为了改进低能次级束逆运动学核反应角分布的测量，研制了空心的多环型半导体探测器，用来取代沿用多年的X-Y位置灵敏型半导体探测器. 论述了多环型探测器的优越性，介绍了其制作过程和工艺，给出了已研制成功的十一环探测器的性能测试结果.     

电磁场中带电粒子在非对易相空间的能级

非对易空间效应是出现在弦的尺度下的一种物理效应。 首先扼要介绍了非对易相空间中的量子力学代数、 Moyal Weyl乘法和广义Bopp变换, 然后讨论了电磁场中带电粒子的Hamiltonian算符, 最后给出了其在非对易相空间中的能级情况。     

High Energy Charged Particle Registration in CR-39 Polycarbonated Detector

Track etch rate characteristics of CR-39 plastic detector exposed to ²⁸Si ions of 670 MeV energy have been investigated. Experimental results were obtained in terms of frequency distribution of the track diameter, track density and bulk etching rate. A dependence of the mean track diameter on energy was found. The application of the radiation effect of heavy ions on CR-39 in the field of radiation detection and dosimetry are discussed. Results indicated that it is possible to produce etchable tracks of ²⁸Si in this energy range in CR-39. We also report the etching characteristics of these tracks in the CR-39 detector.     

二维粒子模拟方法及在空间物理中应用

在粒子模拟的PIC(particle in cell)模式中,与场有关的物理量如电磁场等分配在固定的网格点上,而粒子则可在计算区域的任意位置上.设计了一个二维三分量的粒子模拟程序,并用它计算了空间物理中两种常见的物理现象:束流不稳定性和磁场重联.在束流不稳定性问题中,一束速度为V_b=10V_A(V_A为Alfvén速度)的等离子体在背景等离子中运动,通过波粒相互作用可激发沿磁场方向传播的Alfvén波.在磁场重联问题中,具有Harris形态的电流片可自发地引起磁场重联,并且B_y分量的磁场具有四极形分布.     

MRPC探测不同带电粒子的输出信号与工作气体中dE/dx之间的关系

由28个多气隙电阻板室(MRPC)模块组成的探测阵列-STAR/TOFr, 在相对论重离子对撞机(RHIC)实验上获得了大量的数据. 利用质心能量62.4GeV Au+Au对撞的实验数据, 分析了MRPC探测不同带电粒子(K介子、π介子、质子等)时的输出信号与气体中的电离能损(dE/dx)之间的关系, 给出了MRPC的气体电离和雪崩放大一些新的实验结果. 为了进一步解释实验结果, 针对工作条件下MRPC输出信号的特点, 对MRPC的气体电离和雪崩过程进行Monte Carlo模拟, 深入探讨了影响MRPC输出信号幅度的原因.     

医用质子和12C离子束的物理性质研究

质子和重离子在现代放射治疗手段中已起着不可替代的作用， 这主要取决于其独特的物理性质。 利用一步过程和两步过程的物理模型解释了离子能量损失的机制， 同时结合Geant4软件包模拟质子和12C在水中的运输过程， 研究了离子束的物理性质， 并讨论了计算的结果， 说明了质子和12C在医学中应用的优缺点。 Depending on their unique physical properties， proton and heavy ions have taken an irreplaceable role in modern means of tumor treatment. One step process and two step process physical models were employed to explain the mechanism of ion energy loss. The transport process of proton and 12C in water was simulated by Geant4 toolkit to study the physical properties of ion beam. The calculation results were discussed， which showed the advantages and disadvantages of proton and 12C in the medical application.     

改进的物理粘性SPH方法及其在溃坝问题中的应用

在低雷诺数物理粘性SPH方法基础上引入再生核粒子法进行密度重构,既避免了用人工粘性所导致的数值耗散问题,又提高了低雷诺数物理粘性SPH方法的数值稳定性;以溃坝问题为例,对比分析低雷诺数物理粘性SPH方法和本文方法的仿真结果表明,本文方法可有效消除数值不稳定,压强和速度分布更加光滑,粒子秩序更好,可应用于雷诺数较高或粘性不可忽略的流动问题.     

气体喷嘴反冲传输技术及在核科学中的应用

气体喷嘴反冲传输技术是继“跑兔”装置之后发展和完善起来的适合于短寿命核素研究的一种快速而有效的在线脱束方法。 它能够将短寿命核反应产物传输至远离高辐射区的低本底场所进行收集和测量。 该技术已在加速器和反应堆上得到了广泛的应用, 是一种研究核反应、 核谱学和合成与鉴别新元素、 新核素的一种不可缺少的基本实验技术和工具。 描述了气嘴系统的结构、 基本原理、 设计要求以及它的主要特性, 特别是对系统的气体动力学机制以及各种参数对系统特性的影响等进行了讨论。 最后, 综述了它在核物理、 核化学以及质谱学等领域的应用情况, 并且给出了几个应用的典型例子。 The gas jet recoil transport technique is developed and improved as a new rapid and effective on line and off beam method following “rabbit” apparatus in the study of short lives nuclei. It can transport the short half life nuclear reaction products far from high radioactive area for collection and measurement at low background area. This technique has been widely used in the researches with accelerator and reactor. It is indispensable basic experimental technology and tool applied to nuclear reaction, spectroscopy, as well as synthesis and identification of new elements and nuclei. The basic principle, structure, design requirement and main characteristics of gas jet system are described in this paper, especially the mechanism of gas dynamics and the effect of several parameters on the system properties are discussed. Finally, the applications of this technique in several fields such as nuclear physics, nuclear chemistry and mass spectroscopy etc. are comprehensively represented. Several typical applications are also illustrated.     

Improved Particle Swarm Optimization Based on Entropy and Its Application in Implicit Generalized Predictive Control

Setting sights on the problem of input-output constraints in most industrial systems, an implicit generalized predictive control algorithm based on an improved particle swarm optimization algorithm (PSO) is presented in this paper. PSO has the advantages of high precision and fast convergence speed in solving constraint problems. In order to effectively avoid the problems of premature and slow operation in the later stage, combined with the idea of the entropy of system (SR), a new weight attenuation strategy and local jump out optimization strategy are introduced into PSO. The velocity update mechanism is cancelled, and the algorithm is adjusted respectively in the iterative process and after falling into local optimization. The improved PSO is used to optimize the performance index in predictive control. The combination of PSO and gradient optimization for rolling-horizon improves the optimization effect of the algorithm. The simulation results show that the system overshoot is reduced by about 7.5% and the settling time is reduced by about 6% compared with the implicit generalized predictive control algorithm based on particle swarm optimization algorithm (PSO-IGPC).