SiPM耦合塑料闪烁体探测器放大电路设计

Amplifier circuit for a silicon-photomultiplier-coupled plastic scintillator detector

为了解决硅光电倍增器(Silicon Photomultiplier,SiPM)受环境噪声影响大的问题,设计了一款SiPM耦合塑料闪烁体探测器的信号放大电路。以AD8014放大芯片和CR电路构成负反馈选通放大电路,并且与OPA657跨阻式放大电路进行对比。该款电路以RC滤波输入部分和集成运算放大器构成信号放大电路,具有快上升时间及低输入噪声;以CR高通滤波电路作为比较器信号输入能够有效防止信号反射。实验结果表明:该信号放大电路能够有效滤除环境噪声,并且具备快上升时间。将该电路与塑料闪烁体探测器耦合,在室温下对^(137)Cs源进行暗噪声水平和输出信号一致性测量,其输出脉冲上升时间小于12 ns,暗噪声水平低于30 mV,优于跨阻式放大电路。

[Background]The silicon photomultiplier(SiPM)is sensitive to environmental noise,its performance is greatly affected by ambient noise.[Purpose]This study aims to design a negative-feedback selective amplifier circuit for SiPM coupled plastic scintillator detector to reduce the noise and improve the overall performance of SiPM.[Methods]It is compared with the traditional OPA657 transimpedance feedback amplifier circuit.The circuit consisted of an RC filter input and an integrated operational amplifier AD8014 with advantages of a high gain and low input noise.The CR high-pass filter circuit was used as the comparator signal input to further filter out signal noise and prevent signal reflection from interfering with the amplifier.The experimental circuit is simulated using Micro-cap12 to obtain the relevant circuit parameters.Finally,the dark noise level and signal consistency of a^(137)Cs source at room temperature was record,and performance of this amplifier circuit for SiPM coupled plastic scintillator detector was compared with that of the traditional OPA657 transimpedance feedback amplifier circuit.[Results and Conclusions]Comparison results show that the proposed circuit effectively filters out ambient noise and exhibits a fast rise time.The output pulse rise time is found to be less than 12 ns,and the dark noise level is observed to be less than 30 mV,which are better than those of the transimpedance amplifier circuit.