Development of MRPC technology for STAR-TOF

A prototype of multi-gap resistive plate chamber （MRPC） modules with 6 gas gaps of 220 μtm used for the time-of-flight （TOF） detectors has been developed by STAR TOF group. A tray （TOFr） composed of 28 MRPC modules was constructed and operated in STAR for the d＋Au collisions and Au＋Au collisions during 2003 RHIC and 2004 RHIC run. Results show its time resolution is 85 ps with the average efficiency of 95% and clear identification of K/π up to 1.6 GeV and proton/K up to 3.0 GeV.     

Performance of multigap resistive plate chamber in a γ-ray aging test

The aging test of multigap resistive chamber (MRPC) was carried out under conditions of irradiation from a 137Cs γ source facility. The total charge induced at the anode or at the cathode of the MRPC module was about 29 mC. The gamma dose rate was 10-2 Gy.h-1, and the total accumulative radiation dose was 4.3 Gy. After irradiation,there was an obvious degradation in the properties of the MRPC module.     

多气隙阻性板室探测器位置分辨性能的模拟研究

多气隙阻性板室（MRPC）具有效率高、时间分辨优异、性价比高以及便于大面积制造的优点,成为缪子成像技术径迹探测器的良好选择。提高MRPC的位置分辨能力,是近年来的研究重点。本文使用ANSYS Maxwell计算了MRPC的三维静电权场,在此基础上研究了在相同MRPC结构下,读出板背面接地、读出条间距以及宽度占比对MRPC位置分辨能力的影响,同时给出了改善MRPC位置分辨性能的设计建议是读出条间距1 mm、宽度占比50%~60%。     

Performance of multigap resistive plate chamber in a γ-ray aging test

1 Introduction MRPC is a new type of gas detector [1, 2] devel- oped in the last few decades. It has been proposed to be a substitute for the Time of Flight (TOF) detector used in conventional technology in high-energy nu- clear and particle experiments because of its properties of excellent time resolution, high efficiency, simple structure, insensitivity to magnets, and low energy dissipation. The MRPC technology has been adopted for TOF by the STAR group at Relativistic Heavy Ion C…     

A high time resolution multi—gap resistive plate chamber

Research on a single cell Multi-gap Resistive Plate Chamber(MRPC) was carried out for the Time of Flight detector(TOF) R and D of the STAR experiment .The property of the single chamber was tested with the test beam facility T10 at CERN in Geneva,The MRPC was scanned with the test beam to get the efficiency and time resolution at different position of the active area.The HV plateau was also measured.The time resolution is 65 ps which satisfies the requirement of STAR,The working mechanism of the MRPC is also explained.     

MRPC探测快中子研究

介绍了多气隙电阻板室(MRPC)的结构和原理,用蒙特卡罗方法计算了MRPC对快中子的灵敏度,并进行了脉冲中子实验。实验表明,MRPC有望用于飞行时间法测量快中子能谱。     

Performance of two different modules of long-strip multi-gap resistive plate chamber

Long-strip multi-gap resistive plate chamber（LMRPC） were built with（Module 1） or without（Module 2） adhesive tapes and silicones.Their performances were investigated by working gas mixtures of different gradient contents（Test 1:94%freon,5%iso-butane and 1%SF₆;Test 2:90%freon,5%iso-butane and 5%SF₆）.Both the modules achieved 100%efficiency,with time resolutions of 75 and 70 ps.Comparatively,the Module 1 works with a lower applied HV at the higher noise level,and time resolution was not influenced greatly by the adhesive tapes and silicones.     

多气隙电阻板室探测X射线研究

介绍了多气隙电阻板室(MRPC)的结构和原理,用蒙特卡罗方法计算了MRPC对X射线的灵敏度,并进行了脉冲X光机实验.实验表明,MRPC有望作为大面积的阵列探测器用于X射线成像技术研究.     

MRPC辐照性能试验系统设计

研究MRPC探测器的抗辐照性能,对于RHIC-STAR实验MRPC-TOF的长期稳定运行具有重要意义.设计制作了3.7GBq 60Co γ放射源MRPC辐照性能试验系统,并在两种不同剂量率下进行了辐照实验,得到了MRPC辐照前后的性能变化情况.     

电极厚度对MRPC计数率能力的影响

随着加速器亮度的不断提高,对建造TOF系统所需的MRPC探测器的计数率能力的要求也在不断提高。利用DC模型以及二维电阻网络模型,可分析探测器计数率能力随电极厚度的变化关系。本文研究了基于不同电极厚度的MRPC的计数率能力,证实了通过降低电极厚度提高探测器计数率能力的可行性。     

缪子成像系统中二维位置分辨探测器研制

介绍了一种应用于缪子成像系统的新型二维高位置分辨探测器,MRPC探测器的有效面积为1 072 mm×1 072 mm,先后对探测器在宇宙线和X射线下测试其性能,结果表明探测效率高于98%,位置分辨好于272μm。     

MRPC 宇宙线测试技术研究

采用宇宙线测试系统,同时测量两个空间位置对齐的多气隙电阻板室.采用两种不同的事例挑选方法对两个室的性能进行了分析.结果表明,当选取近乎垂直入射的事例时,MRPC的时间分辨、雪崩信号比例等各项性能均得到提高.还研究了pad间串扰对MRPC性能的影响.     

A four-gap glass-RPC time-of-flight array with 90 ps timeresolution

In this paper, we describe the performance of a prototype developed in the context of the ALICE time-of-flight research and development system. The detector module consists of a 32-channel array of 3×3 cm² glass resistive plate chamber (RPC) cells, each of which has four accurately spaced gaps of 0.3 mm thickness arranged as a pair of double-gap resistive plate chambers. Operated with a nonflammable gas mixture at atmospheric pressure, the system achieved a time resolution of 90 ps at 98% efficiency with good uniformity and moderate crosstalk. This result shows the feasibility of large-area high-resolution time-of-flight systems based on RPCs at affordable cost     

工作气体为安全氟里昂时阻性板室的特性

主要描述了在流光工作模式下，用C2H2F4替换CF3Br气体后，阻性板室（RPC）探测效率仍然达到95％左右，时间分辨的FWHM为2ns，是一种很有前途的环保型工作气体。     

新型多条多气隙阻性板探测器的性能测试

为提高德国FOPI系统飞行时间的探测本领,运用新型多条多气隙阻性板探测器对FOPI系统进行升级改造。探测器的制作已完成,为保证探测器的质量,对它们进行了一系列的测量和质量确认。测试结果证明,系统的本底计数率分布在0.2Hz/cm²附近,工作高压9.6kV;利用γ射线放射源测试,时间分辨（包括闪烁体的时间分辨）分布在220～280ps之间;采用质子束流测量,其探测效率可达98%以上,时间分辨可达75ps     

MRPC物理机制研究

主要研究了MRPC单层气隙工作的物理机制.MRPC工作的物理过程可分为初始电离和电子雪崩两个基本点阶段,依据气体导电理论和相关专业软件,可模拟计算出MRPC单层气隙中的感应电流、本征探测效率与时间分辨率等物理参数.将计算结果与实验结果相比,表明在MRPC中,空间电荷效应明显,电子雪崩甚至达到饱和.     

PSpice程序在阻抗板室探测器研制中的应用

研究提出了阻抗板室（RPC）探测器的电子学模型。基于该模型，通过PSpice程序对RPC探测器的电子学读出信号进行了模拟，模拟结果与实验数据和相关的研究结果一致。通过PSpice模拟，能预测RPC探测器的物理性能，为指导RPC探测器的研制提供了一种有效的优化手段。     

Design of Capacitor Blocks with Multi-Channel Switches for Linear Transformer Driver Stages

In the linear transformer driver technology, the low inductance energy storage components and switches are directly incorporated into the individual cavities (named stages) to generate a fast output voltage pulse, which is added along a vacuum coaxial line like in an inductive voltage adder. In this paper, we outline the detailed design concept and the basic parameters of four capacitor blocks with four different types of multi-channel gas switches. The 100 kV capacitor block #1 and #2 incorporate two parallel capacitors (40 nF, 100 kV) and multi-gap multi-channel gas switches with triggering plate or triggering cable. The 200 kV capacitor block #3 and #4 incorporate two capacitors (40 nF, 100 kV) in series and rail-gap gas switches with one triggering rail or two triggering rails. Operating principles of four multi-channel gas switches are illustrated by using the equivalent electrical scheme of each switch. The basic characteristics of four capacitor blocks are given. The effect of stray capacitances on the trigger pulses is also discussed.     

Optimization of Hot Gas Chamber in High Temperature Reactor

The flow field in the hot gas chamber of the High Temperature Gas Cooled Reactor (HTGCR) was studied with the Computational Fluid Dynamics (CFD) program CFX5. On the basis of the experimental studies, the velocity field, pressure field and temperature field in the hot gas chamber and hot gas duct were obtained, and the simulation's accuracy and reliability were validated by comparison with the results of previous experiments. Two other design schemes of the hot gas chamber were calculated in order to determine which hot gas chamber would be optimal for minimizing temperature differences at the inlet of the heat exchanging components. The results indicated that there was much highly turbulent twisting flow in the hot gas chamber, which was responsible for the excellent temperature mixing effect of the hot gas chamber. But the flow in the rib region was calm, and this fact hindered the heat transfer between the hot and cold gas. The temperature mixing coefficient increases with the increase of the hot gas duct's distance from the hot gas chamber. The hot gas chamber without ribs was more beneficial to the heat transfer between air flows with different temperatures, so the hot gas chamber without ribs was indicated as the optimal design.     

Numerical investigations of thermal mixing performance of a hot gas mixing structure in high-temperature gas-cooled reactor

A numerical simulation study was performed to clarify the thermal mixing characteristics of coolant in the core bottom structure of the high-temperature gas-cooled reactor(HTR). The flow field and temperature field in the hot gas chamber and the hot gas duct of the HTR were obtained based on the commercial computational fluid dynamics(CFD) program. The numerical simulation results showed that the helium flow with different temperatures in the hot gas mixing chamber and the hot gas duct mixed intensively, and the mixing rate of the temperature in the outlet of the hot gas duct reached 98 %. The results indicated many large-scale swirling flow structures and strong turbulence in the hot gas mixing chamber and the entrance of the hot gas duct, which were responsible for the excellent thermal mixing of the hot gas chamber and the hot gas duct. The calculated results showed that the temperature mixing rate of the hot gas chamber decreased only marginally with increasing Reynolds number.