Study of Unstable Nuclei by Delayd Neutron Spectroscopy

在该项目中，新设计和建造了飞行时间中子计数器，用于观测β衰变丰中子子核中激发态发射的延迟中子。计数器的性能达到了设计值。用这个计数器，我们于1994年在物理和化学研究所(RIKEN)完成了^&lt；15，17&gt；B的衰变光谱。我们首次用极化测量和中子测量，成功地获得了~(15，17)&C激发态的自旋和宇称。我们正在准备公布这些结果。另外，我们还在1993年用另一台中子计数器测量了~(14)Be的衰变谱，以研究被认为是丰中子核的特征现象的超允许跃迁。虽然我们没有观察到这样的跃迁，但在~(14)&gT；B中新观察到了向低能激发能级提供强跃迁。理解^&lt；14&gt；B的结构是很有趣的。下一次实验将在1995年7月进行。这项研究的部分已经发表。我们关于丰质子核的研究成果已经在几个国际研讨会上提出，我们现在正准备提交。几份期刊和会议上报道了分段探测器阵列的开发，该阵列被设计成与中子计数器耦合。

In the project, time of flight neutron counter was newly designed and constructed to observe delayd neutrons emitting from excited states in neutron rich daughter nuclei of beta-decay. Performance of the counter satisfied the designed value. With this counter, we have done the decay spectroscopy of ^<15,17>B at the Institute of Physical and Chemical Research (RIKEN) in 1994. We have succeeded to obtain the spins and parities of excited levels in ^<15,17>C,for the first time, by using polarized ^<15,17>B and neutron measurements. We are preparing for publish these results. Further experiment will be done.The decay spectroscopy of ^<14>Be was also done in 1993 with another neutron counter to study the super allowed transitions, which is considered to be characteristic phenomena of neutron rich nuclei. Although we could not observe such a transition, strong transition feeding to the low energy excited level in ^<14>B was newly observed. This transition is interesting to understand the structure of ^<14>B.Next experiment will be done in July of 1995. The part of this study was already published.Oue result on the study of proton rich nuclei was presented in several international symposia and we are now preparing to submit. And the development of a segmented detector array, which was designed to be coupled to the neutron counter, was reported in several journals and in meetings.