Investigation on shape transitions and shape coexistences in neutron-rich odd-A and odd-odd nuclei around 100Zr

100Zr附近富中子奇A核和奇奇核的形状转变和形状共存研究

• 批准号: 452176002
• 负责人: Professor Dr. Jan Jolie
• 金额: --
• 依托单位: Department of Physics
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/452176002?language=en
• 关键词: Investigation; shape; transitions; coexistences; neutron

The proposal aims to provide new and improved spectroscopic information on odd-A and odd-odd nuclei in the vicinity of 100Zr mainly by lifetime measurements of low-energy excited states using fast-timing techniques. The goal is to obtain more spectroscopic evidences for the evolution of the neutron and proton single-particle orbitals in this particular mass region. The deduced gamma-ray transition rates will be compared with predictions using analytic collective models based on microscopically derived energy-density functionals which are able to describe the spherical-to-deformed shape transition and shape-coexistence phenomena observed in the vicinity of N = 60 isotones close to 100Zr. The candidates of interest to be measured are the even-odd 101Mo, the odd-even 103Tc and the odd-odd 102Tc nuclei. Other experimental data on the odd-even 99Y nucleus and the N = 59 odd-odd 98Y and 100Nb isotones have recently been acquired and requires to be analyzed. The neutron-rich candidates to be measured are well produced in thermal-neutron induced fission of, e.g. 235U. The experiments will be performed at the “Lohengrin” fission-fragment separator of the Institut Laue-Langevin (ILL) in Grenoble, France. In collaboration with the ILL and other international scientists, 3-4 fast-timing campaigns will be organized by the IKP. The IKP Köln high-performance LaBr3(Ce) detectors will be used for picosecond-sensitive lifetime determination with low-energy gamma rays via gamma-gamma or beta-gamma time-difference measurements. Installation, calibration and surveillance of the experiment will be done by the IKP fast-timing group. The experimental data will be analyzed on the high-speed IKP server using software specially compatible to the ILL data format and optimized for fast-timing analyzes. The new and improved lifetime results obtained will be used to calculate B(E2) and B(M1) transition rates for investigation on collectivity or for being used as input parameters to perform more phenomenological nuclear structure calculations. The new calculations within the framework of the Interacting-Boson-Fermion (-Fermion) model will be performed by theoretical nuclear structure physicists with whom we are successfully collaborating for many years. Our major objective is to obtain an improved insight on the evolution of shape transition and shape coexistence in nuclei close to 100Zr as a function of the proton and neutron number (orbitals) and to publish results and theoretical interpretations.

该提案的目的是提供新的和改进的光谱信息的奇A和奇奇核附近的100锆主要是通过寿命测量的低能量激发态使用快速定时技术。我们的目标是获得更多的光谱证据的中子和质子的单粒子轨道在这个特定的质量区域的演变。推导出的伽马射线跃迁率将与预测使用解析集体模型的基础上微观派生的能量密度泛函，能够描述的球形变形的形状过渡和形状共存现象观察到的附近的N = 60同位素接近100锆。待测量的感兴趣的候选者是偶-奇101 Mo、奇-偶103 Tc和奇-奇102 Tc核。最近获得了关于99 Y奇偶核和N = 59的98 Y和100 Nb奇偶同位素的其他实验数据，需要进行分析。要测量的富中子候选物在热中子诱发裂变中产生良好，例如235 U。实验将在法国格勒诺布尔劳厄-朗之万研究所的“Lohengrin”裂变碎片分离器中进行。在ILL和其他国际科学家的合作下，IKP将组织3-4次快速运动。IKP Köln高性能LaBr 3（Ce）探测器将用于通过伽马-伽马或β-伽马时间差测量，利用低能伽马射线进行皮秒灵敏寿命测定。实验的安装、校准和监督将由IKP快速计时组完成。实验数据将在高速IKP服务器上使用专门兼容ILL数据格式的软件进行分析，并针对快速时间分析进行优化。这些新的改进的寿命结果将用于计算B（E2）和B（M1）跃迁率，以研究集体性或作为输入参数进行更多的唯象核结构计算。相互作用玻色子-费米子（-费米子）模型框架内的新计算将由我们多年来成功合作的理论核结构物理学家进行。我们的主要目标是获得一个更好的洞察力的演变的形状转变和形状共存的原子核接近100锆作为质子和中子数（轨道）的函数，并发表结果和理论解释。