Study of New-Modes of Nuclear Excitation by Means of High-Resolution (p,n) Measurement

通过高分辨率 (p,n) 测量研究核激发新模式

• 批准号: 59540147
• 负责人: ORIHARA Hikonojo
• 金额: $ 1.73万
• 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: 1984
• 资助国家: 日本
• 起止时间: 1984 至 1986
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-59540147/
• 关键词: Fast Neutron Time-of-Flight Analysis; Charge Exchange (p,n) Reaction; Spin-Isospin Excitation in Nuclei; Effective Nucleon-Nucleon Interaction; ガモフ・テーラー遷移

Charge-exchange (p,n) reactions have been proved to be an excellent tool to study new mode s of nuclear excitation , where spin-isospin excitations are observed, for example. The (p,n) reaction has been recently investigated by means of two different proton energies; i.e. (p,n) work at intermediate energy carried out at IUCF (Indiana University Cyclotron Facility), and the other works have been carried out at CYRIC (Cyclotron and Radioisotope Center, Tohoku University) with 35 MeV protons. Due to strong spin-dependent force, the intermediate (p,n) works seem to be much reliable. However, low energy (p,n) reactions may be studied with much better energy resolution. In this project, we have extensively developed the high-resolution measurement by means of the neutron time-of-flight facilities. It should be noted that to achieve a ultimated high-resolution of 100 keV v.s. 30 MeV neutrons a long flight path (44 m) is required. Thus development of the high efficient detector system was also needed.One of the current interests studied by the high-resolution (p,n) measurement is the <0^+> <-!>> <0^-> transition, which carries selectively information on one-pion exchange interaction. We have studied <DELTA> <J^pi> = <0^-> reactions on <^(13)C> , <^(14)N> and <^(15)N> . A shoulder was systematically observed around 50゜ in the angular distributions for the 1/ <2^-> <-!>> 1/ <2^+> and <1^+> <-!>> <1^-> transitions. This shoulder was interpreted as being due to the tensor interaction in the <DELTA> J( <DELTA> L, <DELTA> S) = 0 (1,1) channel. Other topics such as the <0^+> <-!>> <1^+> Gamow-Teller type transition have been extensively studied on s-d shell nuclei. One of the new modes of nuclear excitation, an example for which is <DELTA> J( <DELTA> L, <DELTA> S) = 2(1,1) or 1(1,1), were studied at <E_p> = 41 MeV for heavier nuclei.

电荷交换（p，n）反应已被证明是研究新的核激发模式的极好工具，例如，在其中观察到自旋-同位旋激发。（p，n）反应最近已经通过两种不同的质子能量进行了研究;即在IUCF（印第安纳州大学回旋加速器设施）进行的中能（p，n）工作，以及在CYRIC（东北大学回旋加速器和放射性同位素中心）使用35 MeV质子进行的其他工作。由于强的自旋相关力，中间体（p，n）功似乎更可靠。然而，低能量（p，n）反应可以用更好的能量分辨率来研究。在这个项目中，我们广泛发展了高分辨率的测量中子飞行时间的装置。应该注意的是，为了实现100 keV v.s. 30 MeV中子需要长的飞行路径（44米）。高分辨（p，n）测量的研究热点之一是<0^+> <-！>><0^->跃迁，它选择性地携带关于单π介子交换相互作用的信息。我们研究了<DELTA>&lt;^（13）C&gt;，&lt;^（14）N&gt;和&lt;^（15）N&gt;上的&lt;J^pi&gt; = &lt;0^-&gt;反应.在1/ &lt;2^-&gt; &lt;-！&gt;&gt;的角分布中，系统地观察到50 °附近的肩状物。1/ &lt;2^+&gt;和&lt;1^+&gt; &lt;-！&gt;&gt; &lt;1^-&gt;过渡。这个肩被解释为由于<DELTA>J（<DELTA>L，<DELTA>S）= 0（1，1）通道中的张量相互作用。其他主题，如&lt;0^+&gt; &lt;-！&gt;&gt; &lt;1^+&gt;在s-d壳层核上，Gamow-Teller型跃迁已被广泛研究。一个新的模式的核激发，其中的一个例子是<DELTA>J（<DELTA>L，<DELTA>S）= 2（1，1）或1（1，1），在<E_p>= 41 MeV的较重的核进行了研究。

项目成果

織原彦之丞: Physics Letters B.

织原彦之助：《物理快报 B》

Hikonojo ORIHARA: "Status of CYRIC Neutron TOF Facilities Upgrade" Nuclear Instruments and Methods.

Hikonojo ORIHARA：“CYRI​​C 中子 TOF 设施升级的现状”核仪器和方法。

Hikonojo ORIHARA: "Isovector <DELTA> <J^pi> = <0^-> Transitions Observed in the (p,n) Reactions on <^(13)C> , <^(14,15)N> and the Tensor Part of the Effective N-N Interaction" Physics Letters B.

Hikonojo ORIHARA：“在 <^(13)C> 、 <^(14,15)N> 和张量的 (p,n) 反应中观察到的等向量 <DELTA> <J^pi> = <0^-> 跃迁

織原彦之丞: Nuclear Instruments and Methods.

织原彦之助：核仪器和方法。

西原進: Physics Letters. 160B. 369-374 (1985)

西原进：《物理学快报》160B 369-374（1985）。