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Development of a SQUID-type detector and a study on systematics of neutron optical potential in the energy region from 0 to a few MeV.

SQUID型探测器研制及0～几MeV能量区中子光势系统学研究。

基本信息

批准号：
04680232
负责人：
MATOBA Masaru
金额：
$ 1.09万
依托单位：
KYUSHU 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：
1992
资助国家：
日本
起止时间：
1992 至 1993
项目状态：
已结题

项目摘要

The optical model is the most valid and useful model for neutron cross-section evaluation in the nuclear engineering field. The model describes an averaged interacton between neutrons and nuclei in the wide neutron energy range by using the complex optical potential, U(r, E) = V(r, E) + iW(r, E). Continuing efforts have been devoted to a more precise determination of the neutron optical potential.On the other hand, recent studies have shown that an optical potential derived from the dispersion theory represents both the neutron scattering states and bound states in the wide neutron energy range. The dispersion relation offers a useful method to evaluate optical potential more precisely. Usually W(r, E) must be known in the wide energy range for the analysis based on the relation. So far, however, the imaginary surface potential W(r, E) less than the Fermi-surface energy has not been well investigated because the value is not obtained from experiments directly.From this point of view, in the present work, we have studied the systematics of neutron optical potential. We carried out (d, P) or (p, d) reaction experiments for several nuclei by using polarized beam at RCNP (Osaka University) and evaluated the spreading width, G, of the single particle or hole states. The corresponding W(r, E) was calculated on the basis of the relation G = 2W.Previously obtained data were reanalyzed in the same manner. In addition to this, we made some basic investigation on a new type SSD telescope system for the future experiments related to this subject.From the work in this project, we have established an evaluation method of imaginary surface potential W(r, E) of the neutron optical potential and found the feasibility for further investigations.

光学模型是核工程领域中最有效、最实用的中子截面计算模型。该模型利用复光势U(r， E) = V(r， E) + iW（r， E）来描述宽中子能范围内中子与原子核之间的平均相互作用。人们一直致力于更精确地测定中子光势。另一方面，最近的研究表明，由色散理论推导出的光势在较宽的中子能量范围内既代表中子散射态又代表束缚态。色散关系为更精确地计算光势提供了一种有用的方法。通常需要在较宽的能量范围内知道W(r， E)，以便根据关系进行分析。然而，到目前为止，还没有很好地研究假想的表面势W（r， E）小于费米表面能，因为该值不是直接从实验中得到的。从这个角度出发，本文对中子光势的系统学进行了研究。我们利用大阪大学RCNP的偏振光束对几个原子核进行了（d， P）或（P, d）反应实验，并计算了单粒子态或空穴态的扩散宽度G。根据G = 2W的关系，计算出相应的W（r， E）。以同样的方式重新分析先前获得的数据。在此基础上，对一种新型的固态硬盘望远镜系统进行了一些基础性的研究，为今后与本课题相关的实验做准备。通过本课题的工作，我们建立了中子光势虚表面势W（r， E）的评价方法，为进一步的研究找到了可行性。