Space neutron spectrometer design with SSPM-based instrumentation

The compact, robust nature of the CMOS solid-state photomultiplier (SSPM) allows the creation of small, low-power scintillation-based radiation measurement devices. Monitoring space radiation including solar protons and secondary neutrons generated from high-energy protons impinging on spacecraft is required to determine the dose to astronauts. Small size and highly integrated design are desired to minimize consumption of payload resources.RMD is developing prototype radiation measurement and personal dosimeter devices using emerging scintillation materials coupled to CMOS SSPM’s for multiple applications. Spectroscopic measurements of high-energy protons and gamma-rays using tissue-equivalent, inorganic scintillators coupled to SSPM devices demonstrate the ability of an SSPM device to monitor the dose from proton and heavy ion particles, providing real time feedback to astronauts. Measurement of the dose from secondary neutrons introduces additional challenges due to the need to discriminate neutrons from other particle types and to accurately determine their energy deposition. We present strategies for measuring neutron signatures and assessing neutron dose including simulations of relevant environments and detector materials.     

Simulation and characterization of different setups for gamma ray detection using SiPMs and LYSO scintillators

Silicon photomultipliers (SiPMs) coupled to fast bright scintillators, like cerium doped silicate based crystals, allow the construction of compact gamma ray detectors. In this paper we discuss simulation results obtained from Monte Carlo ray tracing tools applied to SiPM and LYSO systems. We address the importance of three key factors in light propagation: the scintillator wrapping, the coupling medium, and the detector coating. We also propose a simple experiment to verify some of the findings related to the investigation of diffusive wrappings.     

硅光电管-闪烁体探测器γ谱仪研制

实验研制了硅光电管-闪烁体探测器γ谱仪。该γ谱仪用硅光电倍增管代替普通光电倍增管作为闪烁体探测器的光学读出端,配置闪烁体探测器,构成新型γ谱仪。测试结果表明:新型γ谱仪随温度漂移变化程度大;能量线性较好,线性相关度R为0.9987;配置LaBr_3:10%Ce~(3+)晶体,其能量分辨率为4.3%~4.9%;配置NaI(TI)晶体,其能量分辨率为8.4%。     

SiPM耦合LYSO晶体探测器的能量分辨和时间分辨

本文采用符合测量的方法研究了SENLE公司生产的型号为Micro FC-30035-SMT的Si PM光电转换器件耦合尺寸为3×3×10 mm的LYSO晶体组成的闪烁探测器的能量分辨率和时间分辨。该探测器测得22Na放射源能量为511 ke V光子的能量分辨率(FWHM)为16%,时间分辨达135 ps。     

基于GAGG:Ce晶体耦合SiPM的位置灵敏探测器的设计与评估

为满足当前γ相机对高分辨率、低成本、小型化探测器的需求,提出了采用硅光电倍增管（SiPM）耦合GAGG:Ce晶体阵列的方式代替传统的位置灵敏型光电倍增管（PSPMT）耦合晶体阵列的方式以构成新型γ相机探测器,并设计了均匀电荷分配电路（SCDC）和阻抗电桥电路作为探测器的读出电路,同时设计了前沿定时电路作为数据采集触发电路。实验结果表明：当温度为25 ℃、探测器供电电压为28.5 V时,该探测器在511 keV射线的激发下,散点图的峰谷比高达3.84,对511 keV和662 keV射线的平均能量分辨率分别为10.63%和9.71%,具有较好的分辨性能。     

GRM在轨标定探测器的设计和实现

伽马射线监视器（GRM）上搭载的在轨标定探测器（GCD）用于在轨探头的增益控制,对于探测器在轨探测性能的研究具有重要意义。本文对其各部分电子学的原理设计、偏压补偿电路的高低温实验验证及结果分析、投产加工及镶嵌源灌封设计等研制过程进行了描述,对设计中出现的问题加以验证及改进。实验和测试结果表明,探测器的功能正确,且探测效率、峰位漂移变化等性能指标均满足任务要求,从而表明该设计可保证GCD在轨功能的可靠实现。     

基于SiPM的高灵敏度大响应范围的弱光探测系统

为了满足在极低和较高光功率范围内对光信号的探测,提出了基于硅光电倍增管(SiPM)的弱光检测系统,该系统包含自动调节偏压电路、电流-电压转换电路、小信号放大电路和滤波电路。测量不同偏压下SiPM的输出与入射光信号之间的关系,实验结果显示,偏压对SiPM的输出有很大影响,不同偏压下,SiPM的探测能力和探测范围都不相同。此外,该系统对25 pW到1.75μW的光信号都有响应,能在极低和较高光功率范围内对光信号进行连续探测。     

基于SiPM的阵列式X射线背散探测器设计

阵列式探测器是背散射成像设备能够小型化的关键。受限于光电转换器件的灵敏度和转换效率等因素,阵列式探测器设计一直进展缓慢。本文提出使用硅光电倍增管(SiPM)作为核心部件,并从准直器、闪烁晶体和光电转换元件进行阵列背散射探测器设计的新思路。利用X射线特征谱线建立仿真模型,确定闪烁体CSI厚度为1 mm;准直器设计为栅格状,栅格高度4 cm,间隔为6 mm;SiPM尺寸相应为6 mm×6 mm。根据设计结果完成了探测器单个组件的加工,通过实际实验验证设计结果,实验证明合理设计的SiPM可以满足本应用长时、低光照强度以及被探测物体的厚度变化范围较大的要求。     

新型α、β放射性活度测量装置设计

为满足便携式核辐射污染监测系统研制需求,设计了一种基于Si PM的小体积α、β放射性活度测量装置。该装置的探测器部分以塑料闪烁体和Si PM为核心,使用该新型探测器能够保证高灵敏度的同时缩小系统体积;计数器部分以FPGA为核心,包含了去抖动、边沿检测、脉冲计数、数码管显示等单元;探测器输出的微弱电流脉冲信号依次经后级电荷灵敏放大、整形滤波、电平转换电路的处理,最终以标准TTL电平信号的形式输出给脉冲计数器,实现对放射性粒子的实时监测。测试结果表明:装置对α源的探测效率约为43.3%,对β源的探测效率约为11.5%,能够有效完成α、β放射性活度测量。     

Comparative studies of silicon photomultipliers and traditional vacuum photomultiplier tubes

Silicon photomultipliers （SiPMs） are a new generation of semiconductor-based photon counting devices with the merits of low weight, low power consumption and low voltage operation, promising to meet the needs of space particle physics experiments. In this