用于质子滴线附近核素奇特衰变测量的4π硅条探测器阵列的研制

Exotic decay from nuclei near the proton-drip line has been a hot research field of modern nuclear physics around the world. Therefore, developments of 4π charged-particle detector arrays went on in the major laboratory over last years. In this project, a 4π array of silicon strip detectors will be developed which is planned to be used at the first Radioactive Ion Beam Line spectrometer of National Laboratory of Heavy Ion Research of the Institute of Modern Physics, Lanzhou. It consists of one double sided silicon strip detector at the center, six ones on six directions of the center, and quadrant silicon detectors outside. The energy, time and position of particles emitted from nuclei near the proton-drip line will be measured by the array. One- and two-proton detection efficiencies are 75% and 35%, respectively. The position resolution and spatial coverage of this array are higher than others. Therefore, the comprehensive technological index reaches the leading level in the world. The 4π array of silicon strip detectors will be a powerful tool to study exotic decay from nuclei near the proton-drip line for China Institute of Atomic Energy and Shanghai Institute of Applied Physics, CAS.

质子滴线附近核素的奇特衰变现象是当今国际核物理研究的热点领域之一。为此，各大实验室都在研发覆盖4π立体角的带电粒子探测器阵列用以开展这方面的研究。本项目拟研制在兰州重离子加速器国家实验室放射性束流线终端使用的覆盖4π立体角硅条探测器阵列，其主要由三部分组成：中心双面硅条探测器，周边双面硅条与外围离子注入型四分硅。此套阵列可高效率记录质子滴线附近核素奇特衰变产生的轻粒子的能量、时间与空间信息，单质子与双质子衰变的探测效率分别是75%与35%，位置分辨本领与空间覆盖率均高于国外同类探测器阵列，整套技术达到国际领先水平。4π立体角硅条探测器阵列可为中国原子能科学研究院，中国科学院上海应用物理研究所等单位开展质子滴线附近核素奇特衰变测量提供强大的技术支持。

世界各大实验室都在研发大立体角高颗粒度的带电粒子探测器阵列用以开展质子滴线附近核素的奇特衰变现象。项目成功研制了在兰州重离子加速器国家实验室终端使用的4π双面硅条探测器阵列，整套技术达到国际领先水平。它对奇特衰变中发射粒子的全部信息予以记录，即完整地再现了奇特衰变的物理过程，从而为开展质子滴线附近核素奇特衰变测量提供了强大的技术支撑。. 滴线核22Si研究中首次发现其具有β2p衰变模式。利用库仑置换能关系确定了其质量，两质子分离能确定为−108(125)keV，表明它基态双质子非束缚。. 滴线核27S衰变实验首次同时测量了27P第一激发态发射的质子与γ，从而得到迄今最为精确的27P基态质量。基于实验结果，推导出准确的26Si(p, γ)27P共振反应率，确证了现代天体模型在经典新星环境下26Si (p, γ) 27P共振反应率对于26Al产额的影响；在X射线暴核合成中，发现26Al的增量至少是50%。