Time calibration for the end cap TOF system of BESⅢtime-of-flight detector, oiYline calibration, time resolution

The time calibration for end cap TOF system of BESIII is studied in this paper. It has achieved about 110 ps time resolution for muons in dimu events. The pulse height correction using electronic scan curve and the predicted time calculated using Kalman f     

Neutron beam monitor based on a boron-coated GEM

A new thermal neutron beam monitor with a Gas Electron Multiplier （GEM） is developed to meet the needs of the next generation of neutron facilities. A prototype chamber has been constructed with two 100 mm×100 mm GEM foils. Enriched boron-10 is coated on     

用γ放射源测量闪烁体衰减长度的研究

介绍一种利用γ放射源测量闪烁体的衰减长度的方法.这种方法测量速度快,准确性高.在与用宇宙线测量和GEANT4模拟进行比较中,其结果基本一致.这种方法适合闪烁体的批量检测.     

用于中子谱仪密闭型气体探测器的密闭腔研制

为避免高压气瓶带来的人身安全问题、不便携问题和污染工作气体排放问题,气体探测器已由流气型转化为密闭型。密闭型气体探测器可拓展气体探测器的应用范围,提高气体探测器竞争力,其缺点是腔内杂质气体会累积,影响探测器的性能（增益、分辨率和效率）和出现高压打火。本文采用螺旋弹簧密封实现密闭腔的动态高真空密封,采用铝和不锈钢复合板过渡实现铝和不锈钢焊接,采用高温烘烤、真空泵组抽高真空等方法实现密闭腔体净化,尤其是将铝表面微弧氧化技术用于真空腔体的净化。密闭腔微弧氧化后的杂质气体生成率相比未氧化的降低12.1%,杂质气体中氢气含量降低36%,水蒸气、一氧化碳和二氧化碳含量几乎下降1个数量级。腔体1 a内产生的杂质气体含量为0.006%,2个月内产生的水分含量为0.000 5%,可保证探测器2个月内不发生高压打火。研制出的密闭腔体满足中子谱仪密闭型气体探测器物理要求。