脉冲硬X射线能注量测量系统结构设计

确定了利用全吸收法测量硬X射线能注量的技术方案,阐述了能注量测量的基本原理。结合实际测量环境,选择光电管和高密度硅酸镥闪烁体作为测量系统,分析了各个测量组件参数的影响因素。利用蒙特卡罗程序模拟了硬X射线在闪烁体中能量沉积的轴向分布,并计算了光子的透射率,据此确定了硅酸镥闪烁体的厚度为20 mm。完成了准直系统和电磁屏蔽系统的设计,增加了信噪比。     

塑料闪烁体中子探测效率及相对发光产额的标定

利用加速器中子源研究了用于标定塑料闪烁体中子探测效率及相对发光产额的实验技术 ,在四川大学原子核科学技术研究所 2 .5MeV静电加速器上 ,利用T(p,n)和D(d ,n)核反应作为中子源 ,在 0 .6—5MeV中子能区对直径为 40mm ,厚度为 5mm的 1 42 1塑料闪烁体的中子探测效率及相对发光产额进行了测定.A method used for the calibration of neutron efficiency and the relative photo yield of plastic scintillator is studied. T(p,n) and D(d,n) reactions are used as neutron resources. The neutron efficiencies and the relative photo yields of plastic scintillators 1421 (40 mm in diameter and 5 mm in thickness) are determined in the neutron energy range of 0.655—5 MeV.     

New Generation of Large Scale Scintillation Counters for Detection of EAS and Use in Guard Systems of Experimental Physics Setups

The work is dedicated to the discussion of four new types of large-area scintillation counters design intended for detection of EAS and the use in the guard systems of experimental physics setups with low-cost production. The solid counters based on scintillating polystyrene plates are produced by melting clear polystyrene granules with additives in a mirror mold. Other counters are based on lentil-like polystyrene scintillation granules which are a new kind of plastic scintillators produced at IHEP. WLS fibers and SiPM as a photo sensor are used for a light detection. The dimensions of the tested detectors were 500 × 500 and to 1000 × 1000 mm2, their measured light output was up to 180 ph.e.     

Characteristics of the 2 m long scintillation counters measured by detecting 90 MeV protons

The characteristics of scintillation counters measured in a 90-MeV proton beam have been presented. Two-meter long scintillators BC-404 and BC-408, which were viewed from both ends with photoelectron multipliers R1828-01 (PMT) have been used. Both the amplitude and time distributions of the PMT signals are well described by the Gaussian function. It turned out that the amplitude resolution σ(А)/А weakly depends on the type of scintillator and the proton position along the counter, and lies in the interval between 4 and 5%. The best time resolution σ(T) is about 50 ps near the counter ends and 63 ps at the center.     

Die Lichtausbeute des Plastikszintillators NE 102A für Elektronen von 3 bis 11 keV

The light yield of the plastic scintillator NE 102A for electrons has been measured as a function of electron energy between 3 and 11 keV and scintillator thickness between 0,1 and 50 mm. The scintillation response is a linear function of the electron energy down to energies of 4 to 8 keV, these values depending on the scintillator thickness. The light yield of thin scintillation sheets for low energies was observed to be considerately larger than for thicker sheets. Two possible explanations are discussed.     

Role of hot electron transport in scintillators: A theoretical study

Despite recent intensive study on scintillators, several fundamental questions on scintillator properties are still unknown. In this work, we use ab‐initio calculations to determine the energy dependent group velocity of the hot electrons from the electronic structures of several typical scintillators. Based on the calculated group velocities and optical phonon frequencies, a Monte‐Carlo simulation of hot electron transport in scintillators is carried out to calculate the thermalization time and diffusion range in selected scintillators. Our simulations provide physical insights on a recent trend of improved proportionality and light yield from mixed halide scintillators. (© 2016 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)     

有机锡化合物掺杂聚乙烯基甲苯基塑料闪烁体的制备、光学和闪烁性能EI北大核心CSCD

传统的塑料闪烁体由于其低有效原子序数和密度,不适用于能谱探测领域。有机重金属化合物掺杂塑料闪烁体的制备为塑料闪烁体实现能谱探测提供了一种有效途径。而有机锡化合物掺杂塑料闪烁体具有高光峰灵敏度,并保留了塑料闪烁体的快衰减特性。本文通过自由基聚合的方法成功制备了不同浓度2-(三丁基锡烷基)呋喃掺杂的聚乙烯基甲苯(PVT)基塑料闪烁体,并对其光学和闪烁性能进行了测试和比较。其中掺杂20%2-(三丁基锡烷基)呋喃的PVT基塑料闪烁体的透光率可达90%,X射线激发发射光谱主峰位于425 nm处,光产额为6700 ph/MeV,能量分辨率为15.8%@662 keV,衰减时间约为4.3 ns。我们也制备了1英寸直径、掺杂20%2-(三丁基锡烷基)呋喃的塑料闪烁体,具有6300 ph/MeV的光产额和15.8%@662 keV的能量分辨率。     

ST-401薄塑料闪烁体中子能量响应测量技术研究

利用中国原子能科学研究院核工业放射性计量测试中心的5SDH-2串列加速器进行了ST-401薄塑料闪烁体的能量响应实验.选用T(p,n)³He反应和D(d,n)³He反应作为中子源，子源，中子束流采用复合屏蔽体进行准直，源强采用正比计数管和半导体望远镜进行监测，实验测量了厚度从0.16mm到2.00mm的八种规格薄闪烁体的能量响应曲线，对实验的结果的不确定度进行了分析.结果表明探测器的灵敏度随着晶体厚度的增加而增加，对于一定厚度的薄闪烁体，随着中子能量的增加，探测器的能量响应曲线坡度不大. 关键词： 塑料闪烁体 能量响应 正比计数器 半导体反冲质子望远镜     

Study on fast luminescence component induced by gamma-rays in Ce doped LiCaAlF6 scintillators

We discuss the origin of the fast luminescence component induced by fast electrons generated in gamma-ray interactions in Ce doped LiCaAlF₆ scintillators. Although the slow luminescence component induced by Ce³⁺ emissions depends on the Ce concentration in the LiCaAlF₆ scintillator, the fast component is independent. The fast component is suggested to be generated in the host matrix of the LiCaAlF₆ crystal. From quantitative considerations based on Frank–Tamm equation, which shows the light yield of the Cherenkov radiation, the Cherenkov radiation was determined as the origin of the fast component. We, additionally, found that the slow rise time of main Ce³⁺ emissions in the Ce:LiCaAlF₆ scintillator plays an important role to perform the pulse shape discrimination.     

Light yield of plastic scintillators in relation to the energy of external electrons

It is shown that the specific light yield of plastic scintillators irradiated with external electrons is not a constant quantity, owing to the probability of quenching at the surface of the scintillator. The degree of proportionality of plastic scintillators can be influenced by the choice of primary additive and its concentration.     

Szintillationslichtausbeute und ihre Richtungsabhängigkeit als Funktion der Temperatur von Anthrazen-, trans-Stilben- und para-Terphenyl-Kristallen bei Beschuß mitα-Strahlen

The scintillation light yield of thin trans-stilbene, para-terphenyl and anthracene crystals and an organic plastic scintillator bombarded with α-particles of ThB has been measured as a function of temperature betweent=20° C and the melting point. The light yield of all the specimens investigated has been found to be reduced with increasing temperature. In all cases at the melting point the light yield will be zero. The scintillation anisotropy of the organic crystal scintillators also has been investigated over the range of temperature mentioned above, and there it is independent of temperature and retains the value measured at room temperature.     

DT聚变脉冲中子产额的活化测量法

设计了一个测量高强度DT聚变脉冲中子产额的活化探测器.该探测器由中子慢化体、天然银片、塑料闪烁体和光电倍增管组成,其输出电流通过一个小电流计来获取.通过分析探测器在直流标定和脉冲测量两种状态下输出电流的变化曲线,求解出了特征参数,进而推导计算出DT聚变脉冲中子源的产额.实践证明,这种测量方法与传统的活化法相比,减少了对...     

BC501A液体闪烁体对γ射线的光输出响应

研究了对BC501A液体闪烁体对γ射线的光输出响应特性。实验上利用γ放射源(60Co,137Cs)测量了不同光电倍增管高压下,尺寸为Φ5.08 cm×5.08 cm的BC501A液体闪烁体探测器的脉冲幅度谱。利用Geant4软件进行模拟,计算结果与实验数据很好地符合,得到了能量分辨函数及能量刻度曲线。利用Geant4研究了BC501A的脉冲幅度谱的康普顿边缘Ec、康普顿峰Emax及康普顿半高点E1/2与能量分辨率的关系。同时模拟结果显示,随γ射线能量(0.2～3 Me V)的增加,康普顿边缘位置Nc/Nmax从0.8至0.7线性减少。     

Characteristics of a stilbene scintillation crystal in a neutron spectrometer

Various organic scintillators are commonly used as the detecting material for neutrons, but these detectors are less sensitive to gamma rays. In particular, stilbene crystals and BC501A (NE213, EJ301) have good pulse-shape discrimination (PSD) between neutron and gamma-ray events, and have been selected as the media for fast-neutron detection among the organic, inorganic and plastic materials in a mixed radiation field. Although some of the scintillation characteristics of stilbene crystals have been studied, the detailed scintillation characteristics of the crystal are not completely understood. In this study, the light yield, decay time and pulse shape discrimination capability of a stilbene crystal were measured because this crystal is an optimized detector in a large flux of neutrons such as those might be found in cyclotron and charged particle accelerator facilities. The pulse-shape discrimination of neutrons and gamma rays with a stilbene crystal was measured using a ²⁵²Cf neutron source at room temperature. A neutron tagger module was used for the neutron and gamma separation using the charge comparison method in real time. The total pulse width for the charge integration and the delay from the peak-to tail start time were optimized for a better neutron and gamma separation. The relative light yield and decay time of the stilbene crystal scintillator were also measured.     

反射镜多靶串接增益饱和软X光激光实验

利用Mo/Si多层膜软X光反射镜实现了类氖锗软X光激光的双程放大,在顺接双靶总长28mm时,加与不加反射镜相比,软X光激光输出强度增强了40倍左右,已接近饱和;光束发散角减小,增益区厚度变薄,光束的空间相干性改善。当串接四靶总长为56mm时,加与不加反射的软X光激光输出强度没有明显的差异,表明已达到深度的增益饱和。     

An experimental study of the relative response of plastic scintillators to photons and beta particles

A scintillation counting system has been constructed with the use of BC-400 and EJ-212 series plastic scintillators along with a subminiature photomultiplier tube to investigate the effect of increasing plastic scintillator thickness on system-integrated counts. Measurements have been carried out using four different gamma sources with different energies ranging from 6 keV to 1.332 MeV and a Ni-63 beta source with a maximum energy of 66 keV. Scintillator thicknesses ranged from 10 μm to 2500 μm. The response of the system was determined by measuring the integrated counts as a function of scintillator thickness. These experimental findings were used to empirically determine the optimum thickness of scintillator material with which to build a low energy beta detector which discriminates against high energy gamma photons in a mixed radiation field environment.     

高能伽玛相机探测量子效率的蒙特卡罗模拟

探测量子效率（DQE）可被用来精确描述图像噪声通过成像系统的传播特性。根据级联理论,简洁得出了零频噪声传播情况下成像系统的DQE 表达式。采用蒙特卡罗程序MCNP 计算了高能X射线的硬化能谱在六种常用闪烁晶体中的能量沉积分布以及高能伽玛相机的DQE,分析了闪烁晶体的材料和厚度对DQE的影响。模拟结果表明,高密度、高原子序数是影响DQE的主要因素,在同样厚度下,LuAP和LSO转换屏的探测量子效率最高。     

Light collection of the POLAR detector

POLAR is a compact polarimeter dedicated to measuring the polarization of GRBs between 50–350 keV. The light collection of 200 mm×6 mm×6 mm plastic bars has been simulated and optimized in order to get uniform response to X-rays at different points along one single bar. According to the Monte Carlo results, the amplitude uniformity strongly depends on the level of polishing of the scintillator surface and the covering. A uniformity of 89% is achieved with a prototype constructed by a non position-sensitive PMT and an array of 4×4 bars.     

基于DRS4测试板的数字波形分析方法（英文）

使用不同的方法来确定La Br3晶体信号的到达时间。在文中信号经过光电倍增管的放大之后由DSR4测试板进行数字采集,其中DRS4是由瑞士PSI研究所生产的高带宽、低功耗以及快读出时间的开关电容阵列。这些优势使得DRS4很具有吸引力,很多实验将传统的ADC与TDC替换为DRS4。采集的波形可以通过不同的方法进行后续处理。其中包括:(1)恒分甄别、(2)波形拟合、(3)PMT脉冲模型法以及(4)均值过滤法。文中实现的恒分甄别的时间分辨与使用模拟电路获取的平均时间分辨相比没有提高。高斯波形拟合法虽然与数字CFD的结果相当,但是却更加耗时。均值滤波法虽然容易实现,但是通过这个方法得到的时间分辨与采样时间在一个量级。而PMT脉冲模型法得到的平均时间分辨为195.4 ps,优于模拟信号的恒分甄别的时间分辨254.7 ps。     

一种大视场反射光学系统的研究

从Schwarzschild系统出发,基于设计大视场光学系统的同心原则,设计了一种大视场的三反射光学系统.该系统有两个球面反射镜,一个二次非球面镜,系统在频率50 lp/mm处22°×11°的条形大视场范围内具有良好的成像性能,可以用于紫外探测光学系统中.