Systematic investigation of the collective structure of neutron-rich even-even nuclei with 50 < Z < 82 via recoil-distance Doppler shift lifetime measurements of excited nuclear states using the two neutron transfer reaction.

通过使用两个中子转移反应对激发核态进行反冲距离多普勒频移寿命测量，系统研究 50 < Z < 82 的富中子偶偶核的集体结构。

• 批准号: 529851512
• 负责人: Professor Dr. Jan Jolie
• 金额: --
• 依托单位: Institut für Kernphysik
• 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/529851512?language=en
• 关键词: Systematic; investigation; collective; structure; neutron

We plan to perform two-neutron transfer reactions in the 50 < Z < 82 region of the nuclear chart to investigate different nuclear structure phenomena. The nuclei of interest are 152Nd, 156Sm, 160,162Gd, 178Yb, 182Hf, 188W, 194Os and 200Pt which will be populated in a two-neutron transfer reaction using a 18O beam. The beam is provided by the Cologne 10 MV Tandem accelerator with the beam energy around the Coulomb barrier of the corresponding reaction. The Cologne Plunger spectrometer, equipped with 25 high purity germanium (HPGe) detectors and eight LaBr(Ce) detectors, will be used to measure lifetimes. Additionally, solar cells will be placed at backward angles to gate on the recoiling beam-like particles. This feature will allow to measure particle gated gamma-ray spectra which can be used to employ the recoil distance Doppler shift (RDDS) method. Further, the installation of LaBr(Ce) detectors will allow to measure lifetimes using the electronic fast timing in combination with the generalized centroid difference (GCD) method. Both methods are reliable and established method to measure lifetimes in the pico to nanosecond regime. With the resulting lifetimes, reduced transition strengths can be obtained to study the structure of the nuclei. The 152Nd and 156Sm nuclei lie close to the so-called "octupole magic" number N = 88 and are therefore interesting cases to study octupole deformation in this region. The 160,162Gd, 178Yb and 182Hf isotopes are located around the gamma-soft region with low-lying 0+ states. New data on these nuclei will further improve the gamma-soft model which is an analytical solution of the Bohr-Hamiltonian. The higher mass isotopes 188W, 194Os and 200Pt show evidences of triaxiality and especially gamma-softness. The reduced transition strength are important signatures to understand this phenomenon in this region. Lastly, all of these results will be compared to the mean field based proton-neutron interacting boson model to verify and understand the underlying structure.

我们计划在核图的50 < Z < 82区域进行双中子转移反应，以研究不同的核结构现象。感兴趣的核是152 Nd，156 Sm，160，162 Gd，178 Yb，182 Hf，188 W，194 Os和200 Pt，它们将在使用18 O束的双中子转移反应中被填充。束流由科隆10 MV串列加速器提供，束流能量围绕相应反应的库仑势垒。科隆柱塞光谱仪，配备了25个高纯度锗（HPGe）探测器和8个溴化镧（铈）探测器，将用于测量寿命。此外，太阳能电池将以向后的角度放置，以控制反冲的光束状粒子。这一特点将允许测量粒子门控伽马射线光谱，可用于采用反冲距离多普勒频移（RDDS）方法。此外，LaBr（Ce）探测器的安装将允许使用电子快速计时结合广义质心差（GCD）方法测量寿命。这两种方法都是可靠的，并建立了方法来测量寿命在皮科到纳秒制度。利用所得到的寿命，可以获得约化的跃迁强度以研究原子核的结构。152 Nd和156 Sm核接近所谓的“八极魔”数N = 88，因此是研究该区域八极形变的有趣案例。160、162 Gd、178 Yb和182 Hf同位素位于γ-软区附近，具有低的0+态。这些核的新数据将进一步改善γ-软模型，这是一个玻尔-哈密顿的解析解。较高质量的同位素188 W、194 Os和200 Pt显示出三轴性，特别是伽马软性。相变强度的降低是理解这一现象的重要标志。最后，将所有这些结果与基于平均场的质子-中子相互作用玻色子模型进行比较，以验证和理解潜在的结构。