Excitations of Isovector Monopole Resonance in Nuclei

我们利用来自RCNP环形回旋加速器的65 AMev ^7Li束流在^<12>C上（^7Li, ^7Be）反应后产生的衰变中子、来自^7Be第一激发态的430 keV伽马射线和散射^7Be之间的三重符合方法来寻找等矢量巨共振。大阪大学。用于检测0度散射的7Be，使用磁力摄谱仪“Grand-Raiden”。用于探测430 keV伽玛射线和衰变中子，采用了由22个计数器段组成的gs0计数器阵列和由48个计数器段组成的液体中子计数器阵列。我们首次成功地从等矢量非自旋翻转（DELTAS=0）态和等矢量自旋翻转（DELTAS=1）态分别观测到中子衰变。这将有望为发现等矢量巨单极子共振提供一个令人愉快的方向。

We searched for the Isovector giant resonance by means of a tripple coincidence method among decay neutrons, 430 keV gamma-rays from the first excited state of ^7Be and scattered ^7Be following the (^7Li, ^7Be) reaction on ^<12>C using a 65 AMev ^7Li beam from a Ring cyclotron at RCNP.Osaka University. For detection of 7Be scattered at 0 degrees the magnetic spectrograph, "Grand-Raiden" was used. For detection of 430 keV gamma-rays and decay neutrons a GS0-counter array composed of 22 counter segments and liquid neutron counter arrays composed of 48 segments were used. It was found that we could succeeded in observing neutron decays from the isovector non spin-flip (DELTAS=0) states separately from the isovector spin-flip (DELTAS=1) states for the first time. This will hopefully provide a delightfull direction toward the discovery of the Isovector Giant Monopole Resonance.