用于核态寿命测量的X-γ-γ定时符合系统

An X-γ-γ timing coincidence system used for life timemeasurement of nuclear levels

由两只ＢａＦ２闪烁探测器和一只高纯锗探测器组成的延迟符合系统适用于电子俘获衰变和Ｅ０跃迁生成的ｎｓ和ｐｓ量级激发态寿命测量。快符合涉及特征Ｘ射线和相应的级联衰变γ射线测量，系统具有元素和级联选择的优点。该系统对放射性核素１５２￣Ｅｕ进行测量，除得到Ｘ－γ－γ瞬发时间谱的半高全宽度外，还分别得到１２１．７８ｋｅＶ和３６６．４８ｋｅＶ能级的半寿命分别为１．３９５±０．０３５ｎｓ和４８±１０ｐｓ。结果表明该系统适用于Ｚ≥６２的电子俘获衰变研究。

A delayed coincidence timing system consisting of two BaF2 scintillation detectors and a HPGe detector and operating in fast-slow coincidence mode has been set up.It is suitable for the measurement of lifetime in the ns and ps range for nuclear levels populated by EC decay and E0 transitions. The fast coincidences involve characteristic X-rays and cascade γ rays coming from correlated levels. The system has the advantage of both element and cascade choices. Radioactive isotope 152Eu has been measured, The half-lives of 1.395± 0.035 ns and 48± 10 ps are observed for 121.78keV and 366.48keV levels respectively. These results show that the system can be used for the elements of Z≥62 with EC decays.