经验壳模型和近球形142Pm核高自旋态能级结构

通过反应¹²⁸Te(¹⁹F,5n)¹⁴²Pm研究了双奇核¹⁴²Pm的高自旋态能级结构, 建立了¹⁴²Pm核高自旋态能级纲图. 根据能级结构的系统性, 识别了四个两准粒子态. 根据经验壳模型计算建议了几个新建的关键能级的组态. 67微妙同质异能态被指定为一个全顺排四空穴态(πg_7/2^－1d_5/2^－2ν h_11/2^－1)₁₃^－.     

187Pt的转动带性质研究

利用在束γ谱学技术和¹⁷³Yb(¹⁸O, 4n)熔合蒸发反应研究了¹⁸⁷Pt的高自旋态能级结构. 建立了包括3个转动带的¹⁸⁷Pt高自旋态能级纲图. 基于¹⁸⁷Pt周围核结构的系统学和比较带内B(M1)/B(E2)比率的实验值和理论值, 建议上述3个转动带的组态 分别为11/2⁺[615], 7/2^－[503]和1/2^－[521]. 对各转动带的带交叉频率、顺排增益、旋称劈裂等进行了讨论.     

我国核天体物理前沿研究进展

核天体物理是研究微观世界的核物理与研究宏观世界的天体物理融合形成的交叉学科,其主要研究目标是:宇宙中各种化学元素核合成的过程、时间、物理环境、天体场所及丰度分布;核反应（包括带电粒子、中子、光子及中微子引起的反应、β衰变及电子俘获）如何控制恒星的演化过程和结局。近十多年来获得的大量实验和理论研究使核天体物理研究进入了一个蓬勃发展的新阶段。文章总结了以兰州重离子加速器、北京串列加速器和国家天文台为基础,结合国际合作,在核天体物理研究领域对直接测量、间接测量、衰变测量、质量测量、理论计算、网络计算、天文观测等关键科学问题进行的研究进展。也展望了核天体物理的关键科学问题,这些关键问题包括:（1）在地面实验室、尤其是地下实验室开展天体物理能区重要热核反应截面的直接测量;（2）高能区带电粒子反应截面向天体物理能区的合理外推;（3）恒星平稳核燃烧阶段和爆发性天体事件中关键核反应截面的间接测量;（4）爆发性天体事件中所涉及的大量远离稳定线核素的质量、衰变特性和共振态性质的研究;（5）建立并不断完善核天体物理数据库,发展网络模拟程序,系统研究元素核合成的天体场所、丰度分布;（6）宇宙中铁以上元素的来源之谜。Nuclear astrophysics is an interdisciplinary research field. It composes of nuclear physics, which studies micro phenomena, and astrophysics which studies macroscopic phenomena in our world. The main research goals of nuclear astrophysics are:(1) how, when and where chemical elements are synthesized and what is their final abundance distribution in the universe; (2) how nuclear processes (reactions induced by charged particles, neutrons, photons and neutrinos, beta decays and electron capture processes) determine the evolution and the ultimate fate of stars. At present, nuclear astrophysics has been developed into a new prosperous stage with a huge number of experimental and theoretical progresses. This paper summarized the current progress of nuclear astrophysics in China, in the subfiels of direct and indirect measurement of key reactions, measurement of mass and decay, as well as the theoretical calculation and network simulation. In present paper, the prospects to solve the key scientific nuclear astrophysics problems are represented. These key problems include (1) direct measurement of important reactions at astrophysical energies in the laboratory on the earth surface and in the underground laboratory; (2)extrapolation of cross sections at higher energies for the reactions induced by charged particles; (3) indirect measurement of key reactions in the hydrostatic and explosive nuclear processes; (4) study of the mass, the properties of decay and resonant states for the nuclides far from the stability line in explosive astrophysical events; (5) establish and improve the database for nuclear astrophysics, and develop network simulation codes, and systematically study astrophysical sites and abundance distribution of nucleosynthesis; (6) origin of the elements heavier than iron in the universe.     

全剥离离子94mRu44+的衰变研究

在兰州重离子加速器冷却储存环（HIRFL-CSR）上,用等时性质量谱仪首次研究了百微秒量级全剥离离子94mRu44+的衰变。94mRu44+由初级束流112Sn轰击Be靶产生,经过放射性束流线RIBLL2的筛选后注入到等时性设置的实验环CSRe中,并利用安装在实验环中的飞行时间探测器测量离子在CSRe中的循环周期。94mRu44+退激引起的质量改变会带来其循环周期的变化,由此直接观测到了94mRu44+退激到基态的过程。确定了本次实验中衰变事例探测的灵敏区间,并讨论了衰变发生时刻的测量精度。同时,测量了短寿命核素94mRu44+的质量,其半衰期约为100 μs,这是目前储存环质量谱仪测量的最短寿命核素的质量。The decay of the fully stripped ion 94mRu44+ in the order of one hundred microseconds has been studied for the first time by using the Isochronous Mass Spectrometry (IMS) at the HIRFL-CSR facility in Lanzhou. 94mRu44+ was produced via projectile fragmentation of a 112Sn primary beam bombarding on a 9Be production target. After the in-flight separation with RIBLL2, the ions were injected into the experimental ring (CSRe) and then stored there. The revolution times of the stored ions were measured by a Time-of-Flight (TOF) detector. Due to the mass change of a 94mRu44+ ion caused by its de-excitation to the ground state, hence the revolution time change, the decay process of 94mRu44+ could be directly observed in the CSRe. The sensitive window for detection of the decay events and the measurement precision of the decay time have been determined in this work. At the same time, we measured the mass of short-lived 94mRu44+ with the half-life about one hundred microseconds, which is the shortest among nuclides that have been studied by using storage-ring mass-spectrometry.     

Identification of a New Band and Its Signature Inversion in ^174Re

High spin states in ^174Re are investigated via the ^152Sm（^27 AL,5nγ）^174Re reaction and γ - γ coincidence relationships are analysed carefully. A new band is identified due to its spectroscopic connection with the known π1/2^-[541] × ν1/2^-[521] band. This band is proposed to be the ground-state band built on the π1/2^-[541]× ,ν5/2^-[512] configuration in view of the low-lying intrinsic states in the neighbouring odd-mass nuclei. It is of particular interesting that the new band exhibits a phenomenon of low-spin signature inversion, providing a new situation for theoretical investigations.     

在182,184,186Au的πi13/2⊙νi13/2带中寻找旋称反转

为了搜寻¹⁸²Au, ¹⁸⁴Au,¹⁸⁶Au核中πi_13/2⊙νi_13/2转动带的旋称反转, 我们通过¹⁵²Sm(³⁵Cl,5n)¹⁸²Au,¹⁷¹Yb(¹⁹F,4n)¹⁸⁶Au和¹⁵⁹Tb(²⁹Si,4n)¹⁸⁴Au反应对¹⁸²Au,¹⁸⁴Au, ¹⁸⁶Au核进行了在束γ谱学研究. 本工作扩展了这3个核πi_13/2⊙νi_13/2带的能级纲图, 特别是确定了¹⁸⁴Au核πi_13/2⊙νi_13/2带的能级自旋宇称, 发现了低自旋旋称反转现象.     

146Tb的多粒子激发特性研究

利用在束γ谱学技术、通过反应¹¹⁸Sn(³²S,1p3n)研究了¹⁴⁶Tb的高自旋态能级结构. 基于实验测量结果, 建立了激发能达8.39MeV的¹⁴⁶Tb核的能级纲图. 双奇核¹⁴⁶Tb相对于双满闭壳¹⁴⁶Gd核, 多一个质子和缺少一个中子, 它的低位激发态是二准粒子态, 更高的激发态是四准粒子态, 或二准粒子态与其偶偶核芯低位激发态的耦合. 利用经验壳模型对部分全顺排组态的激发能进行了理论计算.     

Properties of the ν7/2-[503]（f7/2） band in 185Pt

High-spin states in ¹⁸⁵Pt have been reinvestigated via the reaction ¹⁷³Yb(¹⁶O, 4n) at a beam energy of 90 MeV. The previously known band based on the ν7/2^-[503](f_7/2) Nilsson orbital has been extended to higher spin states. Properties of the ν7/2^-[503](f_7/2) band have been discussed with an emphasis on the evolution of configuration while increasing the spin.     

Study of the νi13/2－1 band in 189Pt

High-spin levels of ^189Pt have been studied with the in-beam T-spectroscopy method via the ^176Yb（^18O,5n） reaction at the beam energies of 88 and 95 MeV. The previously known ＂vi-1 13/2 band has been confirmed, and its unfavored signature branch extended up to the 31/2^＋ state. Within the framework of the triaxial particle-rotor model, the vi-1 13/2 band is suggested to be associated with the 11/2[615] configuration, and to have triaxial deformation.     

双奇核~(184)Au中πi_(913/2)νi_(13/2)转动带的结构特征研究

利用重离子熔合蒸发反应和在束γ谱学实验方法 ,研究了双奇核184 Au的高自旋态能级结构 .扩展了基于πh9/ 2 ν7/ 2 - [5 14 ]和πi13/ 2 νi13/ 2 2准粒子组态下的转动带能级纲图 ,建立了两个转动带之间以及πh9/ 2 ν7/ 2 - [5 14 ]带与基态的谱学连接 .从而确定了πi13/ 2 νi13/ 2 带能级的自旋和宇称 ,证实了此转动带在低自旋区出现旋称反转 .分析了πi13/ 2 νi13/ 2 带和相邻核转动带的准粒子顺排特征 ,指出此带的第一回弯以及相邻核转动带在低频观测到的顺排异常可能与h9/ 2 质子顺排有关 .