基于LED纳秒级脉冲的SiPM阵列监测电路

SiPM Array Monitoring Circuit Based on LED Nanosecond Pulse

环形正负电子对撞机(CEPC)电磁量能器(ECAL)原型机的探测单元采用硅光电倍增管(SiPM)作为光电转换器件.由于SiPM具有温度依赖性强和响应速度快的特点,需监测电路产生与SiPM响应速度相匹配的脉冲光激发SiPM,对其增益和动态范围进行监测.本文根据模拟仿真结果,设计了基于双NMOS的驱动电路和相应的控制电路,该电路驱动发光二极管(LED)发射纳秒级窄脉冲光,且强度可调.利用光电倍增管(PM T)测得单路LED发光时域特性,脉冲时间宽度约为10 ns.在CEPC ECAL电子学联测中,SiPM监测电路正常工作,批量测得ECAL原型机中SiPM的增益指标,满足原型机的自检需求.

In the prototype of the electromagnetic calorimeter(ECAL) of the circular electron positron collider(CEPC), a silicon photomultiplier(SiPM) is used to convert light to electronic signal as part of detector cell. Due to the strong temperature dependence and fast response speed of SiPM, a monitoring circuit is required to monitor its gain and dynamic range by generating pulse light which matches the response speed of SiPM to excite SiPM. In this paper, based on the simulation result, a dual NMOS-based driving circuit and corresponding control circuit were designed. The circuit drives a light emitting diode(LED) to emit nanosecond-level narrow pulse light with adjustable intensity. The photomultiplier(PMT) was used to measure the time-domain characteristics of single LED light emission, and the time width of light pulse is about 10 ns. In the joint test with the electronics of CEPC ECAL, the SiPM monitoring circuit works as expected, and the gain of SiPMs in the ECAL prototype is successfully measured in batches, which meets the self-test requirement of the prototype.