Study of Spin-Isospin Excitation in Nuclei by the (n, p) Reaction with Monochromatic Neutrons

单色中子的（n，p）反应对原子核中自旋同位旋激发的研究

• 批准号: 01540228
• 负责人: ORIHARA Hikonojo
• 金额: $ 1.54万
• 依托单位: Tohoku University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1989
• 资助国家: 日本
• 起止时间: 1989 至 1990
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-01540228/
• 关键词: Charge Exchange Reaction; (n, p) Reaction; Spin Isospin Excitation; Neutron Induced Reaction; Neutron Time-of-Flight; Neutron Scattering; (n,P)反応; 中性子誘導核反応; 中性子飛行時間測定法; 単色中性子ビ-ム; 原子核のスピン・アイソスピン励起; β^+-崩壊

The purposes of this research are (1) development of monochromatic neutron beams, being capable for the studies in nuclear spectroscopy and reaction dynamics in the En - 40 MeV region, and (2) study of spin-isospin excitation by the (n, p) reaction in nuclei, instead of the so far investigated (p, n) reaction. In order to realize such a difficult research with seconderly beams, emitted charged particles have been analyzed by a magnetic spectrometers equipped with a detector array, constructed in the present work. Also developed are data-taking and analyzing soft-wares.We purchased isotonically enriched ^<6, 7>Li metal for the neutron production targets. The properties of neutron beams were tested using the neutron time-of-flight facilities located in Cyclotron and Radioisotope Center. With the neutron-beam production system including target, neutron collimator and beam stopper, we have obtained a neutron beam with its intensity of 5 x 10^<-6> /muA/sr, and with resolution of less than 7 … More 00keV. (ref. 1) We have carried out the neutron scattering experiments in the course of this project. The 7Li target was bombarded by 37-MeV proton beams to produce 35-MeV neutron beams. Elastically and inelastically scattered neutrons by ^<28>Si were analyzed by the time-of-flight system. The angular distribution of scattering cross-section have been analyzed by the optical-model to investigate the core-polarization effects in the nuclear mean fields. (ref. 2) With the feasibility study of the (n, p) reaction, our final aim of this research is to study ^<12>C(n, p)^<12>B and ^<26>Mg(n, p)^<26>Na reactions. We have obtained preliminary results for the ^<12>C(n, p)^<12>B reaction. For the latter, however, we could not perform the experiment successfully, mainly due to its small cross-sections. A more intense proton beam of 100 muA is needed.As a summary, we have constructed a monoenergetic fast-neutron facilities, which has sufficient specification for a neutron scattering experiment, though it needs more intense primary beams for the (n, p) reaction for heavier nuclei. Less

这项研究的目的是（1）开发单色中子束，能够在EN -40 MEV区域进行核光谱和反应动力学研究，以及（2）在核反应中研究旋转的旋转兴奋性，而不是迄今为止研究的（p，n）反应（p，n）反应。为了实现第二梁的艰难研究，已经通过等效的磁光谱仪与探测器阵列进行了分析，该磁光谱仪在本工作中构建。我们也开发了数据检测和分析的软件器。使用位于回旋子和放射性同位素中心的中子飞行时间设施测试中子束的特性。在包括目标，中子准直仪和梁塞子在内的中子束生产系统的情况下，我们获得了一个中子束，其强度为5 x 10^<-6> /mua /sr，并且分辨率少于7…00 kev。 （参考文献1）我们在该项目过程中进行了中子散射实验。 7LI靶标被37-MEV质子梁轰击，以产生35兆瓦的中子束。通过飞行时间系统分析了 ^<28> Si的弹性和非自由分散的中子。光学模型已经分析了散射横截面的角度分布，以研究核平均场中的核心化作用。 （参考文献2）随着（n，p）反应的可行性研究，我们的最终目的是研究 ^<12> c（n，p） ^<12> b和 ^<26> mg（n，p） ^<26> na反应。我们已经获得了 ^<12> c（n，p） ^<12> B反应的初步结果。但是，对于后者，我们无法成功执行实验，这主要是由于其小的横截面。需要更强烈的100 MUA的质子束。总结，我们已经构建了单烯类快速中子设施，尽管它需要更强烈的（N，P）反应以使其重的核对中子散射实验具有足够的规范。较少的

项目成果

T.Niizeki et al.,新関 隆,他: "FACILITIES FOR NEUTRON INDUCED EXPERIMENTS AT THE TOHOKU UNIUERSITY CYCLOTRON" Nucleas Intrumeues cud Methodes ir Pluysics Reseaskh A. 4287. 455-459 (1990)

T.Niizeki 等人、Takashi Shinseki 等人：“FACILITIES FOR NEUTRON INDUCED EXPERIMENTS AT THE TOHOKU UNIUERSITY CYCLOTRON”Nucleas Intrumeues cud Methodes ir Pluysics Reseaskh A. 4287. 455-459 (1990)

新関隆: "Facilities for Neutron Induced Experiments at the Tohoku University Cyclotron" Nuclear Instruments at Methods. A287. 455-459 (1990)

Takashi Shinseki：“东北大学回旋加速器的中子诱导实验设施”核仪器方法，455-459。

T. Niizeki, H. Orihara, et al.: "Facilities for neutron induced experiment at Tohoku University cyclotron" Nuclear Instruments and Methods in Physics Research. A287. 455-459 (1990)

T. Niizeki、H. Orihara 等人：“东北大学回旋加速器中子诱导实验设施”物理研究中的核仪器和方法。

新関 隆(T.Niizeki): "FACILITIES FOR NEUTRON INDUCED EXPERIMENTS AT THE TOHOKU UNIVERSITY CYCLOTRON" Nuclear Iustruments and Methodes in Physics Research A. A287. 455-459 (1990)

T.Niizeki：“东北大学回旋加速器中子诱导实验设施”核物理研究仪器和方法 A. A287 (1990)。