• 辐射防护监测 •

### 一种基于SiPM的具有高能量分辨率的紧凑型溴化镧γ谱仪

1. 1.中核环保工程有限公司, 北京 100191;
2.中国辐射防护研究院, 太原 030006
• 收稿日期:2019-09-03 发布日期:2020-07-10
• 通讯作者: 刘立业。E-mail:liuliye@cirp.org.cn
• 作者简介:石伯轩(1983—),男,2003年毕业于清华大学工程物理系核工程与核技专业,2007年毕业于日本东京大学系统量子工学系,获硕士学位,2010年毕业于日本东京力学原子力国际核工程与核技术专业,获博士学位,高级工程师。E-mail:shi_boxuan@163.com

### A compact LaBr3:Ce gamma spectrometer based on SiPM with high energy resolution

SHI Boxuan1, LIU Liye2, CAO Qinjian2, XIA Sanqiang2, WANG Xiaolong2

1. 1. CNNC Environmental protection Engineering Co. Ltd. , Beijing 100191;
2. China Institute for Radiation Protection, Taiyuan 030006
• Received:2019-09-03 Published:2020-07-10

Abstract: The PMT-based LaBr3:Ce gamma spectrometer has higher energy resolution than NaI gamma spectrometer, but it has the disadvantages such as large volume, sensitive to magnetic field and high voltage demand. Silicon photomultiplier tube (SiPM) has similar gain and efficiency as PMT, while offering excellent characteristics such as high timing resolution, high magnetic field resistance, low bias and compact size. In this paper, the LaBr3:Ce crystal is coupled with the SiPM array, and the compact LaBr3:Ce γ spectrometer based on SiPM is designed and developed to improve the impact of the shortcomings of SiPM on the performance of gamma spectrometer by reducing noise, optimizing the operating voltage.The noise of working voltage will lead to the deterioration of energy resolution. By designing the CLC-type π filter with passive filter circuit, the high frequency ripple can be filtered by using its different characteristics of DC/AC impedance and the signal-to-noise ratio of working voltage can be increased from 62.6 dB to 74.64 dB before the noise reduction. The minimum energy resolution corresponds to the optimum operating voltage representing a compromise between dark noise, crosstalk, photodetection efficiency, and SiPM gain. The energy resolution at different working voltages is given by experiment, and the optimal working voltage is determined to be 54.8 V. The energy resolution at this voltage is 3.06% (@662 keV), the result of which is very close to 2.89% measured by photomultiplier tube (PMT).

Key words: gamma spectrometer, LaBr3:Ce crystal, SiPM

• TL817