Despite being thought as a kind of near-ideal light signal amplifier, photomultiplier tubes actually will add an additional contribution to the output signal of scintillation detectors when being irradiated. The contribution is rather small for those detectors consisted of various high-yield scintillators and is thought for a long time to not produce any adverse impact. In the paper, through simulation analysis and well-designed reversed experiment, it is demonstrated that not only being widely accepted Cherenkov emission but also fluorescence emission in the input window both plays great role in the additional contribution. Furthermore, it is also verified through experiments that the radiation conversion performance of this contribution is different or even lower than that of common inorganic scintillators. This leads that the merits of low-yield scintillators are lost in coaxial detector and some measurement results corrected based on the standard performance of the scintillators are usually incorrect. To reduce the adverse impact and acquire the requested performance of some new low-yield scintillators, a kind of off-axis detector layout is designed and proved to be effective.

尽管被认为是一种近乎理想的光信号放大器，但光电倍增管在受到照射时实际上会为闪烁探测器的输出信号增加额外的贡献。对于那些由各种高产闪烁体组成的探测器来说，贡献相当小，并且长期以来被认为不会产生任何不利影响。在论文中，通过仿真分析和精心设计的逆向实验，证明了不仅被广泛接受的切伦科夫发射，而且输入窗口中的荧光发射都对附加贡献起着很大的作用。此外，还通过实验验证了这种贡献的辐射转换性能与普通无机闪烁体不同甚至更低。这导致同轴探测器失去了低产率闪烁体的优点，并且根据闪烁体的标准性能校正的一些测量结果通常是不正确的。为了减少不利影响并获得一些新的低产率闪烁体所要求的性能，设计了一种离轴探测器布局并证明是有效的。