研制用于近物所高纯锗伽马谱仪的带电粒子辅助探测阵列

Gamma spectroscopy is one of the important ways to study the nuclear structures. In the traditional gamma spectroscopy research, the gamma rays emitted from the reaction products were detected by an array composed of high-purity germanium (HPGe) detectors. The nuclear structures can be deduced from these measured information. The gamma rays emitted from all the reaction products were collected in the measurement.The deficiency of this method is that the typical gamma rays emitted from the nuclei with small sections are overwhelmed in the background, thus the detailed studies are difficult to carry out. However, interesting nuclear structure phenomenon may exist in nuclei with small sections, the studies of these nuclei have becomed a tendency in nuclear physics. To solve the above problem, the project plan to develop a set of charged particle detection array based on the characteristicthat the pulse signal of CsI detectors can identify charged particles with different mass. The array can be installed in the new HPGe detector array in Lanzhou heavy ion laboratory. Such a joint device will be able to enrich the measurement of the domestic detector and make it possible to study the nuclear spectroscopy of exotic nuclei.

伽马谱学是研究原子核结构的重要手段之一。传统的伽马谱学研究主要利用高纯锗探测器所组成的探测阵列，通过测量核反应过程中生成核放射的伽玛射线，来推断原子核的内部结构。这种方法的不足之处就是对核反应过程中生成的所有原子核的伽玛射线都进行测量，这就使得生成几率很小的原子核所产生的特征伽玛射线完全淹没在其它原子核伽玛射线的本底谱中，细致的研究工作很难开展。对生成几率较小的原子核进行研究是当前国际上核物理研究的发展趋势，这些原子核往往会出现一些非常奇特的核结构现象，并可能蕴含着深刻的物理规律。为解决上述问题，本项目计划是利用碘化铯晶体探测器的脉冲信号可以对不同质量的带电粒子进行辨别的特性，研制一套带电粒子探测阵列，并安装在兰州重离子加速器国家实验室新建的高纯锗探测阵列中。这样的联合设备将能够丰富国内实验装置的测量手段，使我们开展一些奇特原子核的核谱学研究成为可能。

本项目按照计划执行，研究目标顺利完成。本项目的主要研究内容为研制并设计一套带电粒子探测阵列，该套探测阵列可以与兰州重离子加速器国家实验室新建的伽玛终端的高纯锗探测系统配合使用，进行在束伽玛谱学实验测量，从而可以实现反应道标记技术。最终本项目组设计的探测阵列由64块10*10*5cm^3的碘化铯晶体组成，光读出分别为16个雪崩光二极管和48个光二极管，覆盖的立体角为4Pi的20%。我们利用α和γ放射源对该套探测阵列的粒子鉴别能量进行了测试，并对信号的波形进行采集，能够清晰的区分阿尔法粒子和伽玛光子；并于2017年12月将该套探测阵列实际应用于南非iThemba国家实验室的伽玛终端（AFRODITE）上，进行在束伽玛谱学测量，取得了较好的实验效果。项目执行期间发表基金标注的期刊论文8篇，主办学术会议1次，做国际学术会议口头报告1次，国内学术会议口头报告2次，本项目相关工作培养毕业博士生2名，硕士生2名。