储存环中有效鉴别衰变事件的方法及在^(94m)Ru^(44+)寿命测量中的应用

An Effective Method for Identifying Decay Events in Storage Rings and Its Application in ^(94m)Ru^(44+) Lifetime Measurement

兰州重离子加速器冷却储存环上的等时性质量谱仪是开展高电荷态、短寿命同核异能态衰变研究的理想装置。在短寿命高电荷态离子^(94m)Ru^(44+)的寿命测量实验中,我们直接观测到了^(94)Ru的8^(+)态isomer衰变到基态的过程。在观测时间窗口(20μs,180μs)范围内,鉴别出了49个衰变事件。为了能够鉴别出更多的衰变事件,研究了一种基于频谱幅度来指认衰变事件的方法。基于模拟结果,该方法可以有效鉴别(15μs,185μs)内的衰变事件。将新的鉴别方法应用到实验数据处理中,在(15μs,185μs)内,鉴别出了54个衰变事件。基于这54个衰变事件,计算得到^(94m)Ru^(44+)在实验室坐标系下的寿命为194(121)μs。新的寿命结果与之前的结果218(148)μs在误差范围内一致。

The Lanzhou Heavy lon Accelerator Cooling Storage Ring(HIRFL-CSR)is an ideal device for studying the decay of highly charged and short-lived isomers.In the lifetime measurement experiment of the short-lived highly charged ion ^(94m)Ru^(44+),we directly observed the decay of ^(94)Ru from 8+isomer to the ground state,and identified 49 decay events in the observation time window of(20μus,180μs).In order to identify more decay events,a new method based on amplitude of frequency spectrum was studied in this paper.Based on the simulation results,this new method can effectively identify decay events within(15μs,185μs).By applying the new identification method to the experimental data processing,54 decay events were identified within(15μs,185μs).Based on these 54 decay events,the lifetime of ^(94m)Ru^(44+) in the laboratory frame was calculated to be 194(121)μs.The new lifetime result is within the error range of the previous result 218(148)μs.