大面积玻璃RPC模型与性能测试

介绍了可用于粒子探测的大面积玻璃高阻板探测器RPC(Resistive Plate Chamber).使用两块间隔2mm的普通浮法玻璃作为电极,其中充入流动的混合气体(氩气+异丁烷+F134A),工作高压约9600V;性能测试结果,其单室效率可达97%,时间分辨可达到1.8ns.     

RPC读出条的阻抗匹配

文章对高阻板探测器读出条的阻抗匹配问题进行了研究;引入了一个用于计算带状线特性阻抗的经验公式.测量的特性阻抗与经验公式很好地符合,说明这个经验公式可以用于RPC读出条特性阻抗的计算,以改善RPC读出信号的质量,利于RPC探测器性能的测量.     

海拔3220米动量大于4 GeV/c的μ子垂直积分动量谱

我们在云南海拔3220米高山上,利用G-M计数管磁谱仪,测量了动量大于4 GeV/c的宇宙线μ子垂直积分动量谱.实验给出的谱可用一指数函数表示:I（>P）=Q（p+4）^1.86±0.06(cm^-2·sr^-1·s^-1),其中动量P以GeV/c为单位,Q为常数.同时测量了动量在4—23 GeV/c范围μ子的荷电比为N_μ⁺/N_μ^-=1.26±0.11.另外对本谱仪的动量误差问题作了讨论和计算.     

Design and simulations for the detector based on DSSSD

The present paper describes the design and simulation results of a position-sensitive charged particle detector based on the Double Sided Silicon Strip Detector （DSSSD）. Also, the characteristics of the DSSSD and its testing result were are discussed. With the application of the DSSSD, the position-sensitive charged particle detector can not only give particle flux and energy spectra information and identify different types of charged particles, but also measure the location and angle of incident particles. As the detector can make multi-parameter measurements of charged particles, it is widely used in space detection and exploration missions, such as charged particle detection related to earthquakes, space environment monitoring and solar activity inspection.     

水基契伦可夫量能器模型的研究

为了研究极长基线中微子振荡,构造了一个大小为,1m×1m×13m,水基切伦科夫量能器模型.测量得到的水箱的有效衰减长度为(5.74±0.29)m,并且研究了光的收集能力随入射粒子角度变化的关系.同时发展了基于,GEANT4,软件包,包含有详细的光学过程的模拟程序, 所得到的模拟结果与实验测量有很好的一致性. 说明水箱可以作为水基切伦科夫量能器的可行性的方案.     

Comparative studies of silicon photomultipliers and traditional vacuum photomultiplier tubes

Silicon photomultipliers (SiPMs) are a new generation of semiconductor-based photon counting devices with the merits of low weight, low power consumption and low voltage operation, promising to meet the needs of space particle physics experiments. In this paper, comparative studies of SiPMs and traditional vacuum photomultiplier tubes (PMTs) have been performed regarding the basic properties of dark currents, dark counts and excess noise factors. The intrinsic optical crosstalk effect of SiPMs was evaluated.     

Design and performance study of the LEPD silicon tracker onboard the CSES satellite

The low energy particle detector (LEPD) is one of the main payloads onboard the China seismic electromagnetic satellite (CSES). The detector is designed to ascertain space electrons (0.1-10 MeV) and protons (2-50 MeV). It has the capability of identifying the electrons and protons, to measure the energy spectrum and the incident angle of the particles. The LEPD is made up of a silicon tracker system, a CsI (Tl) mini-calorimeter, an anti-coincidence system made by plastic scintillator, as well as electronics and a data acquisition system (DAQ). The tracker is also a kind of E-E telescope; it consists of two layers of double-sided silicon strip detectors (DSSD). The signals emerging from the silicon tracker can be read out by two pieces of application specific integrated circuit (ASIC), which also can generate an event trigger for the LEPD. The functions of the DSSD system in the LEPD for charged particles were tested by 241Am @5.486 MeV α particles. The results show that the DSSD system works well, and has high performance to detect charged particles and measure the position of incident particles.     

A geometric factor calculation method based on the isotropic flux assumption

One of the instruments onboard the China Seismic Electromagnetic Satellite （CSES） is the Low Energy Particle Detector （LEPD）. The primary objective of LEPD is to provide measurements of the fluxes, energy spectra and pitch angles of 100 keV to 10 MeV electrons and protons from 2 to 50 MeV in the Earth＇s magnetosphere. The geometric factor is one of the principle parameters of a detector, which converts the physical quantity-count rate to the particle quantity-flux. In this paper, we calculated the geometric factor of LEPD via computer modeling of an isotropic radiation environment. It was first demonstrated that the radiation intensity related should obey a cosine-law, then a general sampling method of generating this distribution via GPS of GEANT4 was explained. Furthermore, combined with flux normalization, a comparison of the geometric factor calculation of a set of 2-layer detectors with different shapes （cylinder, truncated cone and rectangle） was performed. Results show a generally good agreement between simulation and analytical calculations for the cylinder and truncated cone detectors, and the result of the rectangular one, for which there is no accurate analytical formula, is consistent with the previous simulated results by others. As a practical instance of the 2-layer rectangle detector, the geometric factor of LEPD is 10.336±0.036 m cm2·sr for 10 MeV proton and 8.211±0.032 m cm2·sr for 8 MeV electron.     

地基人工VLF 电波对辐射带电子的调制

辐射带电子的加速与沉降机理是空间物理研究的重要课题.法国DEMETER电磁卫星观测到了美国NPM发射站VLF信号及与之相关的高能电子沉降事例.本研究工作将根据基于回旋共振相互作用的准线性扩散理论,通过对局域投掷角扩散系数的计算,来说明受VLF影响的高能电子的投掷角分布与电子的能量及所处位置的关系.理论计算较好地解释了DEMETER卫星在NPM实验期间所观测到的电子沉降事例.在此基础上进一步讨论了通过人工方式对辐射带高能电子施加影响的效率问题. 关键词： 回旋共振 投掷角散射 电子沉降