硅光电倍增器的变温伏安特性及水汽凝结对伏安特性的影响

为了研究硅光电倍增器(SiPM)在低温下能否正常工作,选取了两种典型的SiPM,通过液氮制冷方式,对SiPM在不同温度下的反向伏安特性进行了研究.结果显示,不同SiPM的过偏压范围(VB～Vb)随温度的变化差别很大,并且微量水蒸气凝结仅对未封装的SiPM伏安特性的Vb～VB段有明显影响.分析实验结果得出,SiPM正常工作电压的范围在很大程度上受到衬底材料中缺陷和陷阱浓度的影响.在低温下工作的SiPM,要求其衬底材料中缺陷和陷阱的浓度更低.在进行SiPM的低温应用和测量时,应密切监视偏压加在Vb～VB区间时,器件的电流是否有变化,而不能只观察击穿之前SiPM的漏电情况.

Voltage Current (I V) Characteristics of SiPM at Different Temperatures and The Influence of Water Condensation on The I V Characteristics

In order to study whether the silicon photomultiplier (SiPM) can work properly at low temperatures, the reverse voltage current (I V) characteristics of two typical SiPMs were tested and analyzed under different temperatures by liquid nitrogen refrigeration. The results showed that the maximum over voltage ranges (VB~Vb) of the two SiPMs vary greatly with temperature, and the condensation of trace water vapor only has obvious influence on the I V characteristics of unencapsulated SiPMs only between breakdown voltage(Vb) and run away voltage(VB). The SiPMs working at low temperatures require lower concentration of defects and traps. When applying SiPM in low temperature environment, one should not only observe the leakage before breakdown, but also closely monitor the current of SiPM when the bias is in Vb~VB.