光电倍增管倍增极信号定时性能的研究

Timing characteristic of photomultiplier studied on dynode signals

介绍一种从光电倍增管倍增极引出快信号的电路。分析了信号的产生机理,研究了它的定时性能。使用两支PhilipsXP2020Q光电倍增管,与BaF2闪烁体组成时间谱仪探头,从D9倍增极引出快信号,在使用Ortec935恒比定时和Ortec567时幅转换的条件下,测量60Co的瞬发时间谱,在2∶1能窗下得到FWHM=138ps的时间分辨。表明,此方法明显改善了谱仪的时间分辨性能。

A circuit for taking out timing signal from one dynode of photomultiplier is described. The generation of dynode signal is analyzed and its timing characteristic is studied. This type of positron lifetime spectrometer consists of a pair of BaF_2 scintillators coupled to photomultipliers XP2020Q and related electronics, which is a fast-slow coincidence system using ORTEC 935 CFD, ORTEC 567 TAC modules. The best timing resolution recorded at 2∶1 energy window by ()^(60)Co is 138 ps in the way of the fast timing signal is taken from dynode 9. It improves the timing resolution of spectrometer very much in comparing with conventional methods.