通过分析多像素光子计数器(MPPC)的工作原理和其光学串话(OC)效应的特点, 提出在使用MPPC输出雪崩信号的幅度或电荷量作为光子计数的参量时, 利用MPPC的OC效应能提高MPPC的光子探测效率的观点, 并从理论上分析了OC效应对光子探测效率的影响。理论分析结果显示, 在这两种光子计数模式下, 利用OC效应能明显提高MPPC的光子探测效率。利用本文模型计算得出当MPPC的雪崩单元数M为1 600个, 忽略OC效应时的光子探测效率等于30%, 光学串话概率等于50%, 以及单脉冲入射光子数均值为10时, 包含OC效应影响的等效光子探测效率可提高50%, 达45%左右。该结果对MPPC在天体物理、粒子物理、荧光光谱探测等弱光探测场合的应用有一定指导意义。

This paper proposes that the photon detection efficiency(PDE) of Multi-Pixel Photon Counter(MPPC) can be improved by the optical crosstalk(OC) effect when taking the output amplitude or output charge of the avalanche pulses as the parameter of photon counting through analyzing the operating principle and characteristics of the MPPC. The influence of the optical crosstalk effect on the photon detection efficiency is analyzed. The theoretical results show that the photon detection efficiency increases significantly by the optical crosstalk effect of the MPPC under these photon counting modes. According to the results calculated by our model, the equivalent photon detection efficiency taking the OC effect into account is increased by about 50%,(i.e.: reaching 45%), if the total avalanche pixel number of MPPC is 1 600, the photon detection efficiency regardless of the OC effect is 30%, the OC probability is 50% and the mean photon number is 10 per light pulse. This result is significant in the application of low light level detection such as astrophysics, particle physics, and fluorescence spectroscopy.