兰州充气谱仪的焦平面探测系统  

Focal Plane Detection System of Gas-filled Recoil Separator in Lanzhou

作　　者：杨华彬[1,2] 郁琳[1,2] 黄天衡[1] 张志远[1] 马龙[1] 黄明辉[1] 李广顺[1] 吴晓蕾[1] 甘再国[1] 

机构地区：[1]中国科学院近代物理研究所,甘肃兰州730000 [2]中国科学院大学,北京100049

出　　处：《原子核物理评论》2013年第3期369-373,共5页Nuclear Physics Review

基　　金：国家自然科学基金资助项目(11120101005;11005128)~~

摘　　要：在兰州充气谱仪上,设计安装了一套新的焦平面探测系统,该系统包括飞行时间(TOF)探测器、盒型硅(Si-box)探测器阵列和反符合(Veto)探测器3部分。Si-box探测器阵列是由3块位置灵敏硅探测器(PSSD)和8块周边硅探测器(SSD)构成,它对注入核的α衰变的探测效率达到80%左右。Si-box探测器阵列与TOF探测器关联可以有效区分注入信号和α衰变信号。Veto探测器与Si-box探测器阵列和TOF探测器关联可以反符合掉高能轻粒子对注入信号和α衰变信号的干扰。简要介绍了PSSD的能量和位置刻度方法。这套探测器系统已经应用于40Ca+175Lu和40Ca+169Tm的实验。实验结果表明,该探测器系统具备很好的本底抑制能力,能够给出干净的α衰变能谱,结合能量-时间-位置关联测量方法可以实现对单原子的探测和鉴别,总体上达到了预期的设计要求。A new designed focal plane detection system was mounted at the gas-filled recoil separator at Institute of Modern Physics, Chinese Academy of Sciences, which consisted of a time-of-flight （TOF） detector, a silicon-box （Si- box） detector array and a silicon veto detector. Three position sensitive silicon detectors （PSSD） were. surrounded by eight side silicon detectors （SSD） without position sensitive, forming a box of the detector open from the front side. The detection efficiency for α-decays of implanted nuclei was about 80%. The anticoincidence condition for the signals from the TOF detector and Si-box detector array was used to distinguish between the pulses originating from the implanted nuclei and their α-decays. The veto detector information was used to discriminate events due to high-energy charged particles. External energy calibration and position calibration of PSSD are described concisely in this work. This system has been used in experiments of 40Ca＋175Lu and 40Ca＋169Tm. Clean α-decay spectra obtained in these reactions indicated the detection system has a good performance in background suppression. Evaporation residues can be identified by the energy-time-position correlation method. On the whole, the new designed focal plane detection system has achieved the design requirements.

关 键 词：焦平面探测系统 飞行时间 位置灵敏硅探测 周边硅探测器 充气谱仪 盒形硅探测器阵列 

分 类 号：TL817.6[核科学技术—核技术及应用] O571.6[理学—粒子物理与原子核物理]