Spin Resonances in Nuclei

本项目是对原子核中自旋-半自旋激发的合作科学研究项目，旨在研究大坂大学核物理研究中心和荷兰格罗宁根大学KVI回旋加速器研究所的“Nureei中的自旋激发”。本财政年度，我们首次测量了在450 MeV的^3He轰击能量下，经^<90>Zr（^3He，t）^<90>N带^<71>Ga（^3He，t）^<71>Ge反应的Gamow-Teller共振的γ衰变。这些研究对太阳中微子探测以及对核自旋激发的基本理解具有重要意义。这些数据对理解双衰变也很重要.本文讨论了在AGOR回旋加速器和RCNP装置上研究等矢量超巨共振的实验方案. AGRO回旋加速器可以在1995年10月加速第一束。束流传输线已经建立。磁谱仪可以测量与衰变中子和质子同时发生的（^3He，t）反应。本文进一步讨论了与“EuroSuperNovae”计划合作开展的研究中微子吸收截面的工作，其中质子-质子和质子-核碰撞中的γ发射过程是研究Ⅱ型超新星爆炸机制的主要内容之一。理论研究正在进行中。高能γ射线探测的实验装置已在KVI基本完成。

The present project for the cooperative scientific ininvestigation of the spin-sisospin excitations in nuclei aims to study the "Spin Excitations in Nuelei" in both the cyclotron institutes at RCNP (Research Center for Nuclear Physics, Osaka University) and at KVI (Groningen, The Netherlands). This fiscal yaer, we have measured, for the first time, the gamma decay from the Gamow-Teller resonances via the ^<90>Zr (^3He, t)^<90>N band ^<71>Ga (^3He, t)^<71>Ge reactions at the ^3He bombarding energy of 450 MeV.These studies are important to give basic data for the solar neutrino detection as well as the basic understanding of the spin excitation in nuclei. The data are aslo important in uderstanding the double deta decay.The experimental program of investigation the isovector monopole giant resonaces are discussed in the AGOR cyclotron facility as well as in the RCNP facility. The AGRO cyclotron could accelerate the first beam in October 1995. The beam transport line has been established. The magnetic spectrometer is ready for the measurement of the (^3He, t) reactions in coincidence with decay neutrons and protons. We futhemore discuss the collaboration work accociated with the "EuroSuperNovae" project, in which the neutrino absorption cross-sections by nuclei are studied in order to understand the explosion mechanisms of typeII supermovae.The gamma emittion processes in the protonproton and proton-nucleus collisions are one of the syubjects to be studied in this project . Theoretical studies are in progress very much. The experimental setup for the detection of the high energy gamma rays are mostly finished at KVI.