奇特核186Re的谱学研究

The study of the controlled release energy of a long-lived isomer has aroused great interest in the nuclear filed recently. Owing to the high K and long half-life of exotic nucleus 186Re, it is considered as the most suitable subject for studying the induced release energy. However, due to the absence of known intermediate states (IS) by which the resonant photoexcitation and depletion reactions could proceed, the study of isomer manipulation of 186Re is at a standstill. In this project, high-energy excited states above the high K isomer of 186Re will be populated by incomplete fusion reaction induced by the weakly bound nucleus 7Li, in order to identify the possible intermediate states (IS) present in pathways from the ground state to the isomer and vice versa which is very important for the study of isomer manipulation in 186Re.

长寿命同核异能态的可控核退激是近年来核物理领域的一个研究热点。奇特核186Re，由于其高K长寿命同核异能态（寿命20万年）的存在，被认为是一个理想的候选核。然而，由于其高K同核异能态之上的中间核态信息缺乏，对其可控核退激的研究一直停滞不前。本顶目将利用弱束缚7Li诱发的非完全熔合核反应机制，布居位于高K同核异能态之上的核态，寻找186Re中高K同核异能态可能的受激及退激中间核态路径，为186Re可控核退激研究提供关键的实验数据。

本项目拟利用弱束缚核7Li诱发的非完全熔合蒸发核反应186W(7Li,alpha-3n)，布居186Re高K同核异能态之上的谱学信息，寻找此核中高K同核异能态可能的受激及退激中间核态路径，为186Re可控核退激研究提供关键的实验数据。由于新冠疫情影响，实验推迟到2022年3月份。在项目的执行期间，我们详细分析了日本大阪大学7Li+186W实验的186W(7Li,alpha-3n)反应道分支，对186Re激发态可能的中间态进行了评估。同时，我们对Chiara, C. J. 等人的文章[Nature 554, 216–218 (2018)]中同核异能态可控核退激NEEC过程进行的仔细的评估，对他们的实验数据提出了质疑，结果发表在Nature 594, E1–E2(2021)上。我们在近物所RIBLL1上开展了93Mo同核异能态可控受激退激实验，得到NEEC过程几率小于2*10^-5，与Chiara等人的结果相关3个量级。