Effect of the integrated time of the induced current signal on the position resolution of the RPC detector

A prototype RPC with position resolution less than 1 mm has been produced and studied. Based on this RPC detector, the effect of the width of the integrated FADC time window on the position resolution of a RPC has been studied experimentally and theoretically. The results of theoretical calculation and experimental measurement have shown good agreement.     

Measurement of avalanche size and position resolution of RPCs with different surface resistivities of the high voltage provider

The effects of surface resistivity of the high voltage provider on the space dispersion of the induced charge of a prototype Resistive Plate Chamber (RPC) have been studied experimentally and theoretically. The results of both experiment and theory agree and confirm that a two-Gaussian function can be used to fit the dispersion of the induced charge of the RPC. It is shown that the Gaussian function with the narrower width is mainly due to the expansion of the avalanche charge in the gas gap of the RPC, and the Gaussian function with the larger width is due to the charge dispersion when it passes through the resistive carbon film. This will be useful in the RPC design when one wants to make an RPC with high position resolution.     

Test of BESⅢ RPC in the avalanche mode

The installation of the BESⅢ RPC system has been completed.Cosmic ray test results show that they perform very well in streamer mode and meet the BESⅢ requirements.We have tested several RPCs in the avalanche mode with the addition of extra SF6 in the gas mixture.We find an efficiency plateau that reaches～95%.and a time resolution of 1.8 ns.This demonstrates that the BESⅢ-type RPC can work in the avalanche mode as well.     

全尺寸CMS RE1/2阻抗板探测器样器束流测试结果

介绍了CMS RE1/2 全尺寸阻抗板探测器的束流测试结果.探测器气体室的阻抗板表面采用不需要淋油的特殊光洁处理,外支撑框架采用铝质蜂窝板,以保证足够的强度以及整个RPC所占空间尽量小.在GIF的束流测试结果表明该样品在高辐射本底下能够达到满探测效率.时间分辨率以及噪声水平都符合CMS实验的要求.     

多隙阻性板室(MRPC)的性能和工作气体关系的模拟研究

多气隙阻性板室(MRPC)以其优良的时间分辨率在粒子物理实验中被用作飞行时间(TOF)探测器. 国际合作项目RHIC-STAR采用MRPC作TOF. 我们已成功地制作出30多个MRPC, 并安装在RHIC-STAR上. 通过模拟计算软件Magboltz,计算了MRPC常用工作气体的物理参数, 并根据气体探测器物理机制, 重点分析了MRPC性能与其工作气体之间的相互关系, 此分析对优化RPC与MRPC混合气体组分是有益的.     

Beam Test Results of the First Full-Scale Prototype of CMS RE1/2 Resistive Plate Chamber

We reported the muon beam test results of the first full–scale prototype of CMS RE1/2 Resistive Plate Chamber (RPC).The bakelite surface is treated using a special technology without oil to make it smooth enough.The full scale RE1/2 RPC with honeycomb supporting frame is strong and thin enough to be fitted to the limited space of CMS design for the inner forward RPC.The muon beam test was performed at CERN Gamma Irradiation Facility (GIF).The detection efficiency of this full scale RPC prototype is>95% even at very high irradiation background.the time resolution (less than 1.2 ns) and spatial resolution are satisfactory for the muon trigger device in future CMS experiments.The noise rate is also calculated and discussed.     

Measurement of avalanche size and position resolution of RPCs with different surface resistivities of the high voltage provider

The effects of surface resistivity of the high voltage provider on the space dispersion of the induced charge of a prototype Resistive Plate Chamber （RPC） have been studied experimentally and theoretically. The results of both experiment and theory agree and confirm that a two-Gaussian function can be used to fit the dispersion of the induced charge of the RPC. It is shown that the Gaussian function with the narrower width is mainly due to the expansion of the avalanche charge in the gas gap of the RPC, and the Gaussian function with the larger width is due to the charge dispersion when it passes through the resistive carbon film. This will be useful in the RPC design when one wants to make an RPC with high position resolution.     

二维位置灵敏硅探测器的应用研究

对二维位置灵敏硅探测器进行了239Puα源刻度测试,并在弹性散射实验中使用了二维位置灵敏硅探测器.考察了两种定位方法在实验中与测试中的一致性.测量了二维位置灵敏硅探测器的能量分辨率、位置分辨率和位置畸变.对位置畸变进行了定性理论解释.     

A simulation study of the e~+/e~- sensitivity of a low resistive phosphate glass electrode in a RPC using GEANT MC

The resistivity of conventional glass is quite high and is unacceptable in a high rate environment. Low resistive glass-electrodes could be a solution for this problem. The present study reports the e+/e-simulation results of an RPC detector made from low resistive phosphate glass electrodes. The detailed geometrical configuration of the content materials which are the essential components of the glass of the RPC detector have been created with the GEANT4 simulation code. Two different types of particle sources, i.e. for e+/e-, have been located on the detectors surface to evaluate the performance of the phosphate glass RPC. Both of the particles have been simulated as a function of their respective energies in the range of 0.1 MeV – 1.0 GeV. The present simulation work has shown that the resistive electrode plays an important role for the particle production in the RPC configuration.     

Layer-by-layer analysis of structures containing δ-layers by secondary ion mass spectrometry taking into account the TOF.SIMS-5 depth resolution function

The depth resolution function of the TOF.SIMS-5 secondary ion mass spectrometer has been studied for several types of analyzed structures under different experimental conditions. A numerical algorithm for calculating the depth distribution profile of an element for a given structure model taking into account ion mixing, induced roughness, and information depth has been realized. The values of the depths of the thin near-surface layers (??-layers) of Ge in a Si matrix and Si in a GaAs matrix were determined by fitting the calculated profiles to experimental ones by varying parameters of the resolution function. It is shown that determination of the depth of the ??-layer from the peak position on the experimental profile yields a large systematic error, account of which noticeably increases the accuracy of estimating the delta-layer??s position.     

A fast muon trigger for the PHENIX forward spectrometer upgrade

The PHENIX forward upgrade adds nosecone calorimeters and level-1 trigger (LVL-1) detectors to the muon forward spectrometers. The muon detector will trigger on high pT muons from W decay and reject background. This will enable study of quark and anti-quark polarizations in the proton. The upgrade will add momentum and timing information to the present muon trigger. Signals from 3 Resistive Plate Chambers (RPCs) will provide momentum and timing information for the LVL-1 trigger. Each RPC carries a plane with coarse structure to establish a space point for timing and one with radial cathode strips for azimuthal resolution. Timing resolution of ≈ 2 ns rejects beam-related backgrounds and tracking from RPCs minimizes muons from hadron decays. RPC information is sent by optical. bers to LVL-1 trigger processors. A discussion of physics measurements possible, layout of the upgrade and details of RPC design and tests are given below. for the PHENIX collaboration Presented in the Poster Session “Future Experiments and Facilities” at the 18th International Conference “Quark Matter 2005”, Budapest, Hungary, 4–9 August 2005.     

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.     

Energy spectrum of cosmic protons and helium nuclei by ahybrid measurement at 4300 m a.s.l.

The energy spectrum of cosmic Hydrogen and Helium nuclei has been measured below the so-called "knee" by using a hybrid experiment with a wide field-of-view Cherenkov telescope and the Resistive Plate Chamber (RPC) array of the ARGO-YBJ experiment at 4300 m above sea level. The Hydrogen and Helium nuclei have been well separated from other cosmic ray components by using a multi-parameter technique. A highly uniform energy resolution of about 25% is achieved throughout the whole energy range (100-700 TeV). The observed energy spectrum is compatible with a single power law with index γ=-2.63±0.06.     

ARGO-YBJ detector simulation using GEANT4

‘G4argo＇, a GEANT4-based simulation package for the ARGO-YBJ detector, is described in this paper. C4argo incorporates in the simulation the true RPC time resolution and another 0.5 ns time uncertainty which is introduced from the offline calibration of TDC. In addition, the correct RPC geometry and the true materials for the ARGO-YBJ experimental hall are implemented. As a result, G4argo simulation shows a very good agreement with real data.     

ARGO-YBJ detector simulation using GEANT4

'G4argo', a GEANT4-based simulation package for the ARGO-YBJ detector, is described in this paper. G4argo incorporates in the simulation the true RPC time resolution and another 0.5 ns time uncertainty which is introduced from the offline calibration of TDC. In addition, the correct RPC geometry and the true materials for the ARGO-YBJ experimental hall are implemented. As a result, G4argo simulation shows a very good agreement with real data.     

HIRFL-CSR外靶终端上硅微条探测器阵列的搭建

硅微条探测器因具有很强的位置分辨率与能量分辨率而在世界各大核物理实验室得到广泛应用。中国科学院近代物理研究所研制了性能优越、位置精度达到0.5 mm×0.5 mm的双面硅微条探测器,用于HIRFL-CSR的外靶实验终端谱仪(ETF)上,用作径迹测量以及△E-E望远镜系统△E的探测。硅微条探测器体积小、集成度高,利用柔性印刷电路板(FPCB)引出信号,配合ASIC芯片的前端电路,能够方便地给出每一条的能量信息和位置信息。在此详细阐述了在HIRFL-CSR的ETF上双面硅微条探测器阵列的搭建,并测量了放射源在真空中探测单元的能量分辨本领。结果表明,该硅条探测器的每个探测单元对5~9 MeV能量的α粒子的能量分辨率在1%左右。     

Primary vertex in the ALICE experiment in absence of the event reconstruction

ALICE is a general-purpose apparatus for the study of ultra-relativistic heavy-ion collisions at the Large Hadron Collider of the CERN. The study of such reactions demands the determination of the primary vertex in three dimensions with good resolution. We have developed an algorithm for finding the vertex position even in absence of the event reconstruction. The performances of such an algorithm have been studied as a function of the vertex position, particle multiplicity and magnetic field.     

Generation of X rays at the grazing incidence of 18-MeV electrons on a thin Si crystal in a betatron chamber

The generation of X rays at the grazing incidence of 18-MeV electrons with a 50-μm-thick Si crystal 4 mm in length along the electron beam has been studied. The crystal has been placed in a goniometer inside the chamber of a B-18 betatron. The results exhibit strong changes in the angular distribution of bremsstrahlung at the variation of the orientation of the crystal. This effect is not observed in the case of the normal incidence of electrons on the surface of a thin crystal where the channeling of electrons, which occurs at certain orientation of the crystal, is absent. Images of a reference microstructure have been obtained with a high resolution of details of the microstructure owing to the smallness of the source of radiation. The dependence of the contrast of an image on the position of the microstructure in the radiation cone has been demonstrated.     

The spatial resolution of the CMS ME1/1 muon station cathode strip chambers with CRAFT08 data

The spatial resolution of the outer part of the ME1/1 muon station has been studied with CRAFT08 (Cosmic Rays At Four Tesla-2008) data at the CMS detector (CERN). The ME1/1 Cathode Strip Chamber (CSC) layer spatial resolution as a function of the CMS solenoid magnetic field is presented. The influence of the strip width and anode wire tilt on the spatial resolution has been studied. Finally, the spatial resolution for the ME1/1 6-layer CSC was calculated and the ME1/1 outer part spatial resolution was estimated.     

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。