194 resultados para Kipke, Harry G.
Resumo:
Using a shell model which is capable of describing the spectra of upper g(9/2)-shell nuclei close to the N = Z line, we study the structure of two isomeric states 7(+) and 21(+) in the odd-odd N = Z nucleus Ag-94. It is found that both isomeric states exhibit a large collectivity. The 7(+) state is oblately deformed, and is suggested to be a shape isomer in nature. The 21(+) state becomes isomeric because of level inversion of the 19(+) and 21(+) states due to core excitations across the N = Z = 50 shell gap. Calculation of spectroscopic quadrupole moment indicates clearly an enhancement in these states due to the core excitations. However, the present shell model calculation that produces the 19(+)-21(+) level inversion cannot accept the large-deformation picture of Mukha et al.
Resumo:
We calculate the in-medium nucleon-nucleon scattering cross sections from the G-matrix using the Dirac-Brueckner-Hartree-Fock (DBHF) approach. And we investigate the influence of the different representations of the G-matrix to the cross sections, the difference of which is mainly from the different effective masses.
Resumo:
We experimentally investigate the shell effect on the stabilization processes following the multi-electron transfer in slow collisions of Arq+-Ar (q = 6-9, It) The relative cross-section ratios of multi-electron transfer and of the subsequent stabilization with respect to single-electron capture are measured meanwhile compared with the theoretical results predicted by the classical over-barrier model. Our result indicates that the multi-electron transfer is dominant when the projectile charge is large and the subsequent stabilization shows a dramatic variation if the projectile L-shell configuration becomes open. It shows that the subsequent stabilization processes of multiply excited scattering ions have a strong dependence on the projectile shell. (C) 2010 Elsevier BV All rights reserved.
Resumo:
Medium-spin states of Ge-70 have been studied via the Ni-60(C-12,2p gamma)Ge-70 reaction at 45 MeV. The ground-state band and the second 0(+) band have been extended to the 12(+) and 8(+) states, respectively. Two negative-parity bands, one of which has a coupled structure and the other has a decoupled structure, have been observed additionally. Although the latter decoupled structure was known up to the (21(-)) state from a previous experiment, the part of the level scheme up to the 15(-) state has been largely modified by the present experiment. Backbendings observed in the positive- and negative-parity yrast bands have been compared with those of the neighboring even Ge isotopes. The experimental level structure has been compared with the shell-model calculations in the model space (2p(3/2), 1f(5/2), 2(p1/2), 1g(9/2)) employing two kinds of effective interactions, one of which is an extended P + QQ interaction with monopole interactions and the other is developed from a renormalized G matrix. Microscopic structures of the observed bands have been discussed with the help of the shell-model calculations.
Resumo:
采用5台1.5W/4.2KG-M制冷机(日本住友RDK415D)并联研制出了1台方便实验室使用的小型氦液化装置,并为其建立了性能测量实验台。实验结果表明:液氦温度为4.17K(饱和压力为96kPa)时,氦液化率为74L/d;液氦温度为4.42K(饱和压力为121kPa)时,液化率为116L/d,经拟合,在4.2K(饱和压力为100kPa)时液化率为83L/d,并且通过100小时以上的连续运行,说明该氦液化装置自循环性能良好。通过实验发现:实测氦液化率远大于制冷机冷头制冷量对应的计算氦液化率。分析认为:G-M制冷机气缸壁对氦气预冷是提高实际氦液化率的主要因素。
Resumo:
本论文在 166MeV 的束流能量下,利用重离子熔合蒸发反应 142 Nd(32 S, 1p3nγ )170 Re 布居了 170 Re 的高自旋激发态,用 12 套带 BGO反康普顿抑制的高 纯锗探测器阵列进行了在束 X-γ 和γ γ − 符合测量。在 210MeV 的束流能量下, 利用重离子熔合蒸发反应 146 Nd(35 Cl,5nγ )176 Ir 产生具有 β+ / EC 衰变性质的 核素 176 Ir, 由氦喷嘴快速带传输系统将反应产物送到低本底区,用一台小平面探 测器、一台轴对称型高纯锗探测器和一台 CLOVER 探测器进行了γ γ − 符合和 t γ − 单谱测量。基于这些测量结果,研究了 170 Re 的高自旋态和 176 Ir 的 β+ / EC 衰变性质。 本工作基于γ−γ符合关系及周围邻近核已知信息的综合分析,首次建立了包 括 16 个能级 26 条γ 跃迁的双奇核 170 Re 的转动带能级纲图,并利用推转壳模型、 粒子转子模型等对其进行了分析和讨论。根据实验提取出的准粒子顺排、 Routhian、旋称劈裂等结构信息和邻近双奇核带结构系统学知识的比较分析,指 出该带的两准粒子组态是 11/213/2 hi π ν ⊗ ,并且该带在低自旋出现旋称反转。 基于对 176 Ir 核 β+ / EC衰变实验数据的离线处理分析,对早先发表的 176 Ir 衰 变γ 跃迁进行确认的同时又发现了 4 个新能级和 13 条新的γ 射线,丰富了 176 Os 核的低位激发态能级纲图。根据典型γ 射线的衰变时间谱建议了 176 Ir核的一个长 寿命低自旋同核异能态,同时通过两准粒子耦合的半经验计算建议了其组态。