New method for level-lifetime measurements with thick scintillators
New method for level-lifetime measurements with thick scintillators
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DOI：
10.1016/j.nima.2023.168525
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发表时间：
2023-07-14
影响因子：
1.4
通讯作者：
Zhu, S.
中科院分区：
文献类型：
--
作者：
Crider, B. P.;Prokop, C. J.;Zhu, S.
能级寿命提供了对原子核结构的关键洞察，并作为理论描述的严格测试。虽然存在几种方法来确定反应测量和衰变研究的水平寿命，这里的重点是技术，涉及直接测量的人口和随后的激发态的人口减少之间的时间差。本文中呈现的技术广泛地适用于多个定时范围，但是该方法是针对飞行定时方法来具体描述的。多步，振幅依赖的时间游走校正和定时分辨率校正被用来解决使用厚的电子探测器所产生的数据分析的复杂性。随后，一个新的Monte Carlo方法利用测得的探测器响应从数据中获得，再加上卡方最小化，提出了提取激发态寿命GSIM; 100皮秒。该蒙特卡罗方法的框架是为具有已知1.6 ps半衰期的68 Zn中的状态的衰变而开发的，考虑到该技术的检测灵敏度，该状态被认为是迅速的，然后使用富中子Ni同位素中具有120（34）ps和1.05（3）ns半衰期的另外两个激发态进行基准测试。使用这种新的方法，它考虑到厚闪烁体使用，这些相同的半衰期被测量为135（10）ps和1.04（24）ns，分别。整体良好的一致性证明了该技术的有效性。
Level lifetimes provide key insight into the structure of atomic nuclei and serve as stringent tests of theoretical descriptions. Though several methods for determining level lifetimes exist for both reaction measurements and decay studies, here the focus is on techniques involving the direct measurement of time differences between population and subsequent depopulation of excited states. The techniques presented herein are broadly applicable across multiple timing ranges, but the approach is specifically described for the fly timing method. A multi-step, amplitude-dependent time walk correction and timing resolution corrections were employed to address the data analysis complications that arise from using thick scintillators for electron detection. Subsequently, a new Monte Carlo method utilizing measured detector responses obtained from the data, coupled with chi-square minimization, is presented for extracting excited state lifetimes & GSIM; 100 picoseconds. The framework of this Monte Carlo method is developed for the decay of a state in68Zn with a known 1.6 ps half life, which is considered prompt given the detection sensitivity of the technique, and then benchmarked using two other excited states in neutron-rich Ni isotopes with 120(34) ps and 1.05(3) ns half lives. Using this new method which takes into account the thick scintillator used, these same half lives were measured to be 135(10) ps and 1.04(24) ns, respectively. The overall good agreement demonstrates the validity of the technique.