多气隙电阻板室的宇宙线测量结果

介绍了20多个多气隙电阻板室的宇宙线测量结果.测量所用的宇宙线平台可以同时测量同一个电阻板室的多个cell,其参考时间的时间分辨为70ps.在宇宙线的测量条件下,用国产材料制作的多气隙电阻板室的时间分辨可达到90ps.利用这套宇宙线测量系统,还对多气隙电阻板室的探测效率和cell间的相互串扰进行了研究.     

MRPC宇宙线批量测试方法探讨

通过分析33个多气隙电阻板室(MRPC)的宇宙线测试结果, 得到了雪崩信号比例和 平均幅度与时间分辨的关系, 计算得出了MRPC的分辨时间随测试事例数的变化 趋势. 据此提出了~MRPC~的宇宙线批量测试方法.     

一个高时间分辨的多间隙电阻板室原型

研制了一种多气隙电阻板室原型并建立了相关的测试系统.利用宇宙线测试系统和欧洲核子中心的试验束装置T1?0对其性能进行了测试,给出了初步结果.时间分辨达到70ps,对最小电离粒子的探测效率大于95%.     

利用ICCD定位宇宙线来测量探测器时间分辨的方法研究

本研究采用双层150 mm×150 mm闪烁条阵列定位宇宙线的入射和出射位置. 阵列信号光使用波移光纤吸收传输,在ICCD相机前插入前置像增强器,使信号光延迟大于200 ns, 使ICCD可以由外部高速触发信号控制,有效记录随机触发事例.该宇宙线定位系统可以同时多点密集测量 通用探测器测试平台的时间分辨和闪烁光的渡越时间.该新方法与传统时间分辨测量方法相比提高了30倍以上 的效率.实验结果显示:时间探测器的时间分辨好于200 ps,满足通用探测器测试平台的设计要求.     

多气隙电阻板室飞行时间谱仪技术

基于多气隙电阻板室(MRPC)技术的飞行时间谱仪广泛应用于现代物理实验,并在粒子鉴别中发挥了重要作用.随着加速器能量和实验亮度的提高,对飞行时间谱仪的粒子计数率和时间分辨要求越来越高.MRPC飞行时间谱仪按技术上可以分成三代.从第一代到第三代,计数率要求越来越高( 30 kHz/cm~2),时间精度也更加严格(20 ps),相应的探测器结构和读出电子学系统呈现出不同的特性.本文总结了三代飞行时间谱仪技术的主要技术特点及主要物理实验,介绍了已经取得的应用成果,提出了该技术的未来发展方向.同时也介绍了MRPC探测器在工业及医学方面的应用.     

高时间分辨MRPC的位置灵敏读出方法

根据MRPC工作机制和高时间分辨的特性, 研制一种位置灵敏MRPC原型及读出方法. 该探测器具有10个220μm气隙, 有效探测面积为20cm×20cm. 前端电子学采用专用ASIC芯片, 具有快时间响应和输入电荷-输出信号宽度的转换功能. 采取同时读取信号传输时间差和感应信号分布的方法实现两维读出. 对该探测器性能的束流测试结果显示: 沿着读出条方向及其垂直方向的位置分辨分别为4.5mm和1.6mm, 其时间分辨达到63ps, 探测效率>95%.     

闪烁光纤量能器单元模型的宇宙线测试

介绍闪烁光纤量能器单元模型宇宙线测试采用的简易实验装置和测量步骤,以及实验数据的分析处理方法.对来自意大利KLOE的铅–光纤量能器单元模型进行了宇宙线测试,对实验数据进行了分析和修正,给出了该单元模型的时间分辨(252ps)和位置分辨(4.1cm)等参数.     

环形正负电子对撞机带电粒子鉴别的飞行时间探测器

环形正负电子对撞机(circular electron-positron collider, CEPC)通过d E/dx的测量进行长寿命带电粒子的鉴别,要求对d E/dx的测量达到约3%的精度.但d E/dx的测量对带电粒子π/K,π/P和K/P各有一个分辨盲区,对应的横动量分别为1 GeV/c, 1.6 GeV/c和2 GeV/c.一种解决方案是采用高精度飞行时间(time of flight, TOF)探测器填补分辨盲区,探测器系统的时间分辨要求小于50 ps.针对这一要求本文提出一种小颗粒飞行时间探测器,具体方案为采用小块塑料闪烁体(1 cm×1 cm×0.3 cm)侧面耦合硅光电倍增管读出.介绍了该探测器的构建以及利用90 Sr电子准直源和高速波形采集电子学对该探测器的性能标定.结果显示,采用恒比定时法,该探测器的时间分辨约为48 ps,可以满足CEPC对飞行时间探测器的要求.     

TOFr在STAR实验中的标定方法

基于多气隙电阻板室(MRPC)的STAR飞行时间探测器的一个板条的原型(TOFr)参加了2003年STAR实验的质子–质子对撞和氘–金对撞的物理运行.利用STAR实验中原有的赝顶点位置探测器(pVPD)和时间投影室(TPC),结合TOFr的时间及幅度信号,并考虑TOFr每个探测单元的尺寸,对影响时间分辨的各种因素进行了修正,实现了对TOFr的标定.实验数据给出的TOFr的本征时间分辨为85ps,在两倍标准方差下,其对π/K及K/p分辨的动量分别达到了1.6GeV/c和3.0GeV/c,大大提高了STAR探测器的粒子鉴别能力.     

电子束时间聚焦技术

利用时间展宽分幅相机研究电子束的时间聚焦现象.当阴极未加载脉冲电压时,测得相机的时间分辨率为80ps.当阴极加载斜率为14V/ps的脉冲电压、电路延时为11.395ns时,相机的时间分辨率为8.8ps,电子束的时间宽度经历了被压缩到被展宽的过程.改变阴极脉冲下降沿斜率,研究电子束时间聚焦时系统时间分辨与下降沿斜率的关系.当下降沿斜率为1V/ps时,时间分辨近似等于80ps,电子束到达微通道板时其时间宽度约等于原始宽度.当斜率大于1V/ps时,时间分辨小于80ps,到达微通道板时电子束时间宽度被展宽.当斜率为0.5V/ps时,时间分辨大于80ps,到达微通道板时电子束时间宽度被压缩.     

MRPC-TOF时间性能和刻度方法的研究

研制的由28个多气隙电阻板室(MRPC)模块构成飞行时间探测系统, 从2003年以来在RHIC-STAR实验上成功运行并获得了大量的实验数据. 为了深入了解MRPC实际运行中的性能,采用质心能量200GeV的Au-Au对撞的实验数据, 对MRPC-TOF的刻度方法进行了深入研究, 主要包括: (1) 对现有的刻度方法做了进一步的改进; (2) 对粒子入射角度等因素进行了修正; (3) STAR径迹重建的位置分辨率对MRPC时间分辨率影响. 用改进后的刻度和修正方法, 计算得到MRPC的本征时间分辨率为大约60ps, 与束流实验结果相近.     

Performance study of new style mosaic MRPC

The Compact Muon Solenoid (CMS) at LHC intends to use a high rate trapezoid MRPC for the muon system upgrade, but the size of the MRPC is limited by the dimensions of low resistivity glass. We have designed a prototype of a large MRPC in which the electrodes are developed by gluing two pieces of glass plates. Simulation of the weighting field and cosmic ray test shows that the efficiency of the glued MRPC is higher than 96% and the time resolution is better than 71 ps.     

A prototype MRPC beam test for the BESⅢ ETOF upgrade

A prototype multi-gap resistive plate chamber (MRPC) with a 2×6 gap structure is developed for the upgrading of the endcap time-of-flight (ETOF) detector in the Beijing Spectrometer (BESⅢ). The prototype MRPC is tested in the E3 beam line of the Beijing Electron Positron Collider (BEPC) with secondary charged particles (π and p, etc) of 600 MeV/c. The test results show that the time resolution of the MRPC can reach 50 ps and that the detection efficiency is greater than 98%.     

Online aging study of a high rate MRPC

With the constant increase of accelerator luminosity, the rate requirements of MRPC detectors have become very important, and the aging characteristics of the detector have to be studied meticulously. An online aging test system has been set up in our lab, and in this paper the setup of the system is described and the performance stability of a high-rate MRPC studied over a long running time under a high luminosity environment.The high rate MRPC was irradiated by X-rays for 36 days and the accumulated charge density reached 0.1 C/cm~2.No obvious performance degradation was observed for the detector.     

Status of the front-end-electronics for the time-of-flight measurements at the MPD experiment

The preamplifier based on the ASIC NINO for the Time of Flight system (TOF) of MPD/NICA was developed and tested. The signal is read from both sides of the strip of the multi gap Resistive Plate Chamber (MRPC). In total there are around 14000 channels of electronics. To measure time of flight of secondary particles from collision of heavy ions on the collider NICA the Time over Threshold (ToT) method is used. According to the bench tests the preamplifier board showed stable work and good time resolution <10 ps for one channel. It was also tested at the test beam facility of the Nuclotron. The time resolution of the TOF detector which used the described preamplifier was reached ～42 ps.     

Performance testing of a long-strip two-end readout multi-gap resistive plate chamber

Multi-gap Resistive Plate Chamber (MRPC) is a new generation of gas detector with good tim-ing and spacial resolution, whose technique is widely applied in some recent high energy (nuclear) physics experiments. In this letter, we report a long-strip two-end readout MRPC and its test beam performance. The measurements show that the long-strip performs a transmission line characteristic and the impedance is independent of the length of strip. The MRPC module we developed is presented to gain a timing resolution of～80 ps and a spacial resolution of ～6.4 mm. The possible application of the MRPC is also discussed.     

Prototype of time digitizing system for BESⅢ endcap TOF upgrade

The prototype of a time digitizing system for the BESⅢ endcap TOF (ETOF) upgrade is introduced in this paper. The ETOF readout electronics has a distributed architecture. Hit signals from the multi-gap resistive plate chamber (MRPC) are signaled as LVDS by front-end electronics (FEE) and are then sent to the back-end time digitizing system via long shield differential twisted pair cables. The ETOF digitizing system consists of two VME crates, each of which contains modules for time digitization, clock, trigger, fast control, etc. The time digitizing module (TDIG) of this prototype can support up to 72 electrical channels for hit information measurement. The fast control (FCTL) module can operate in barrel or endcap mode. The barrel FCTL fans out fast control signals from the trigger system to the endcap FCTLs, merges data from the endcaps and then transfers to the trigger system. Without modifying the barrel TOF (BTOF) structure, this time digitizing architecture benefits from improved ETOF performance without degrading the BTOF performance. Lab experiments show that the time resolution of this digitizing system can be lower than 20 ps, and the data throughput to the DAQ can be about 92 Mbps. Beam experiments show that the total time resolution can be lower than 45 ps.