Study of High-spin Levels in Spherical Nucleus139Ce and Transitional Nucleus189Pt

本论文主要包括以下两部分： 利用能量为 50 MeV 的 12C 束流，通过反应 130Te(12C,3n)产生了 139Ce 的高自旋态。基于标准在束核谱学实验方法，利用由 14 套BGO（AC）HPGe 探测器组成的探测器阵列，进行了 X- γ-t 和γ - γ -t 符合测量，更新并扩展了139Ce 的高自旋能级纲图.139Ce的能级结构具有球形原子核的典型特征，其高自旋态是由单粒子激发形成的。本文利用经验壳模型计算了 139 Ce 的多准粒子激发态能量，研究了其高自旋激发态的多准粒子特性。 利用能量为 88 和 95 MeV 的 18O 束流，通过重离子熔合蒸发反应 176Yb(18O,5n)，布居了 189Pt 的高自旋激发态。实验采用 GEMINI γ射线探测器阵列，进行了 X- γ-t 和γ-γ -t 符合测量。基于γ - γ符合关系、 γ射线相对强度、强度平衡原理和交叉跃迁等信息，建立了新的 189Pt 高自旋态能级纲图。实验观测到基于υi113/ 2 ，υf 5/2(p3/2) 和υi113/ 2 ，υf 5/2(p3/2)组态的转动带以及多准粒子激发能级。其中， υi113/ 2 带的优惠和非优惠旋称分支分别被扩展到 49/2+和 31/2+能级。本工作利用三轴粒子-转子模型分析了基于υi113/ 2 ，υf 5/2(p3/2)组态的转动带性质，分析了它们波函数的主要成分，并建议它们分别具有三轴形变和长椭形变。实验上发现结构非常相近的两个能级序列，我们建议它们具有组态。第一次利用粒子-转子模型计算了这个基于三准粒子组态的转动带能级能量，很好地再现了实验结果，并建议此带具有扁椭形变。由于与这个组态相应的 Nilsson 轨道量子数显示了赝自旋量子数特征，我们建议此三准粒子组态转动带为赝自旋伙伴带

Properties of the rotational bands in the transitional nucleus 189Pt

High-spin states in 189Pt have been studied experimentally using the 176Yb(18O,5n) reaction at beam energies of 88 and 95 MeV. The level scheme of189Pt has been revised significantly and extended to high-spin states.Rotational bands have been analyzed in the framework of triaxial particle-rotor model, and a γ ≈−30◦triaxial shape and a near-prolate shape have been proposed to the νi−113/2 and νf5/2(p3/2) bands, respectively. Two ΔI = 2 transition sequences with similar energies have been observed, and they have been proposed to be associated with the νi−213/2νf5/2(p3/2) configuration. The structure built on the νi−213/2νf5/2(p3/2) configuration could be interpreted theoretical calculations of the triaxial particle-rotor model if a near-oblate shape is assumed

Study of the νi13/2－1 band in 189Pt

High-spin levels of 189Pt have been studied with the in-beam γ-spectroscopy method via the 176Yb(18O,5n) reaction at the beam energies of 88 and 95 MeV. The previously known νi-131/2 band has been confirmed, and its unfavored signature branch extended up to the 13/2+ state. Within the framework of the triaxial particle-rotor model, the νi-113/2 band is suggested to be associated with the 11/2[615] configuration, and to have triaxial deformation

~(139)Ce的多准粒子激发态

利用能量为50MeV的12C束流,通过反应130Te(12C,3n)布居了139Ce的高自旋态．基于标准在束核谱学实验测量结果,扩展并更新了139Ce的能级纲图．139Ce的能级结构具有球形原子核的典型特征,其高自旋态由单粒子激发形成．利用经验壳模型计算了139Ce的多准粒子激发态能量,研究了其高自旋激发态的多准粒子特性

Clover探测器的极化测量

介绍了利用Colver探测器测量γ射线的线性极化方法.用~(60)Co源对其进行测试,有效地测量了γ射线的电磁属性,从而确定了能级的宇称