Study of two nucleon interaction in nuclei with neutron capture reaction on deuterium

核力中的二体和三体相互作用部分地支配着原子核中的二核子运动。虽然这些相互作用已经被用来解释原子核中的各种现象，但明确的证据还没有显示出来，特别是三体相互作用。本研究的目的是探讨两核子相互作用在Triton中与^2H(n, np)n和^2H(n,γ)^3H反应的作用，以分离三体力的影响。我们利用^7Li(p, n)^7Be反应产生的中子束进行了实验。能量范围从40到90兆电子伏的质子束由东北大学回旋加速器实验室提供。平均中子强度约为1mhz，比要求的低了一百倍。我们使用了一种由三层氘化液体闪烁体构成的活性氘靶。最终状态下的反冲或发射的质子在活动靶中产生触发信号。GSO晶体和NE213闪烁探测器分别探测到n+^2H过程最终态的r射线和中子。它们是根据来自活动目标的信号进行测量的。采用本课题开发的基于VME+PC/LINUX的在线数据采集系统进行数据采集。获得了初步的数据，以讨论该实验下一阶段的发展。我们发现，要进行^2H(n,γ)^3H测量来讨论原子核中的两个核子运动，需要很强的单能中子束。

Two-nucleon motions in nuclei are partially dominated by two and three body interactions in nuclear force. Although these interactions have been introduced to explain various phenomenons in nuclei, the clear pieces of evidence have not been shown yet, especially three body interaction. The aim of the study is the investigation of the role of two nucleon interaction in Triton with ^2H(n, np)n and ^2H(n,γ)^3H reaction, in order to separate the effect of three body force.We carried out the experiment using neutron beams produced by the ^7Li(p, n)^7Be reaction. The proton beams in an energy range from 40 to 90 MeV are provided from the Cyclotron laboratory, Tohoku University. The average neutron intensity was about 1 MHz that is hundred times lower than that of required.We used an active deuteron target which is made of the three layered deuterized liquid scintillator. The recoils or emitted protons in the final state produce the trigger signals in the active target. The r-rays and neutrons from the final state of the n+^2H process are detected GSO Crystals and NE213 scintillation detectors, respectively. They are measured in coincidence with the signals from the active target. The online data acquisition system based on the VME+PC/LINUX, which were developed in this project, was employed to take data.The preliminary data were obtained to discuss the development to the next stage for this experiment. We found that much intense mono-energetic neutron beams are required to carry out the ^2H(n,γ)^3H measurements to discuss two nucleon motions in nuclei.