LHAASO-WFCTA硅光电倍增管增益温度漂移精确补偿方法

大型高海拔空气簇射观测站(Large High Altitude Air Shower Observatory,LHAASO)的广角切伦科夫望远镜阵列(Wide Field of View Cherenkov Telescope Array,WFCTA)采用新型的固态半导体探测器硅光电倍增管(silicon photomultiplier tube,SiPM)作为光敏探测器.由于SiPM的增益对温度较为敏感,为使SiPM增益在变温环境下保持稳定,本文研究出了SiPM增益温度漂移的精确补偿方法.该方法通过粗调和细调两个数字电位器的方式实现对低压差线性稳压器(low dropout regulator,LDO)输出偏压的调节,并根据刻度出的模数转换器(Analog-to-Digital Converter,ADC)监测值与真实偏压的关系,利用ADC的监测值进行反馈调节的方法实现偏压的精确调节,最终实现SiPM增益的精确补偿.通过使用以该方法实现的电路后,在相似温度变化范围内,SiPM的增益波动由补偿前的71.8%降低至0.8%.结果显示该方法能够实现对因温度引起的SiPM增益漂移的很好的补偿.

Precise compensation method for gain temperature drift of silicon photomultiplier tube of LHAASO-WFCTA

The Wide Field of View Cherenkov Telescope Array (WFCTA) of Large High Altitude Air Shower Observatory (LHAASO) uses silicon photomultiplier tube (SiPM), a new solid state semiconductor detector, as a photosensitive detector. Since the gain of SiPM is sensitive to temperature, in order to keep the gain of SiPM stable under the environment of variable temperature, a precise compensation method for SiPM gain temperature drift is developed in this paper. The method realizes the bias adjustment of LDO output by means of coarse and fine adjustment of two digital potentiometers. According to the relationship between the calibrated ADC monitoring value and the real bias voltage, we uses the ADC monitoring value for feedback regulation to realize the precise bias adjustment, and finally obtain the accurate compensation of SiPM gain. Using the circuit realized by this method, the gain fluctuation of SiPM is reduced from 71.8% before compensation to 0.8% within the similar temperature variation range. The results show that this method can achieve a good compensation effect for SiPM gain temperature drift.