中子数N=50核88Sr的高自旋态

在用82Se束流和天然Ba靶之间的深部非弹反应研究类靶余核激发态时,Ba靶严重氧化,88Sr的激发态由16O与82Se之间的融合蒸发反应产生,通过对束γ谱学方法测量了88Sr的退激γ射线,提取了γ跃迁的DCO系数和角分布各向异性因子,对所有能级进行了自旋指定,在已知能级之上观测到了两个高自旋异性因子,对所有能级进行了自旋指定,在已知能级之上观测到了两个高自旋能级结构,自旋,激发能分别达到13h,8520KeV和12h,7909KeV,根据能级衰变特征和邻近N＝50同中子素的能级结构系统性,对高自旋态的组态进行了讨论。γ     

135La高自旋态的实验研究

利用在束γ谱实验技术,通过¹²⁸Te(¹⁰B,3n)¹³⁵La反应研究了¹³⁵La的高自旋态.基于γγ符合关系、γ射线的相对强度和各向异性度的测量结果,建立了¹³⁵La的能级纲图.在hω≈0.40MeV附近,观测到基于πh_11/2质子轨道上的负宇称带的带交叉.比较N=78同中子素链能级结构的系统性,认为该带交叉是由一对h_11/2准质子发生转动顺排造成的.在高自旋态处,观测到具有很强M1跃迁、Signature劈裂很小的ΔI=1负宇称带,根据系统性认为该带是建立在πh_11/2(νh_11/2)²组态上的γ≈–60°的扁椭球形变带.     

奇奇核90Nb的高自旋态研究

用能量为80MeV的19F束通过反应76Ge(19F,5n)90Nb布居了90Nb的高自旋态.通过在束γ测量分析90Nb退激γ射线的符合级联关系,发现了19条新的属于90Nb的γ跃迁,建立了90Nb的高自旋态能级纲图.通过经验壳模型计算指定了部分能级的组态,并结合实验DCO比值和与相邻N=49核素的系统比较,确认了新能级的自旋和宇称. The high spin states of~(90)Nb have been populated via reaction~(76)Ge(~(19)F, 5n)~(90)Nb at beam energy of 80 MeV. The de-exciting γ-rays have been measured with in-beam γ-ray spectroscopy method. After γ-γ coincidence analysis, 19 new γ transitions were identified and assigned to~(90)Nb. The new level scheme of~(90)Nb was established. Based on the semi-empirical shell model calculations, the configurations of the levels have been suggested. In addition, the spins and parities of the new levels ...     

过渡区核87Zr的高自旋态研究

通过束流能量为118MeV的⁵⁹Co(³²S,3pn)⁸⁷Zr熔合蒸发反应,用在束r谱学方法研究了⁸⁷Zr的高自旋态.利用7台反康普顿谱仪组成的探测阵列进行r–r符合测量,并确定部分r射线的DCO值,在此基础上建立了自旋直到(37/2⁺)和(43/2^－)的能级纲图.观测到了多条新的能级.与相邻的同中子异荷素的比较表明,中子对核结构性质的影响远大于质子的贡献.随着质子数的增加,第一交叉频率呈减小的趋势.     

High Spin States in Odd--Odd 160Tm Nucleus

High-spin states of ^160Tm are studied by the ^146 Nd（^19F, 5n） reaction at a beam energy of 102 MeV. The previously known πh11/2 ＋ vi13/2 yrast band and πh11/2 ＋ vh9/2 side band are confirmed. The level scheme is enriched and more low-lying levels are observed. A new side band is observed and assigned as the favoured signature partner of πd3/2 ＋ vi13/2. The spin of this band is assigned with the energy level systematics. It is pointed out that the B （M1）/B （E2） ratios increase rapidly at the high frequency approaching the second crossing in the π h11/2 ＋ vi13/2 braid, which is closely related to the alignment gain of the aligned i13/2 quasineutron.     

129Ce高自旋态的形状变化

通过¹¹⁶Sn(¹⁶O,3n)¹²⁹Ce反应,利用多普勒移动衰减法测量了¹²⁹Ce高自旋态的寿命.得到的跃迁四极矩表明¹²⁹Ce的集体性相对于核芯¹²⁸Ce减弱.这个因增加一个h_11/2中子而引起集体性的降低可以解释为由于形状驱动效应产生三轴形变所造成的.正、负宇称带的跃迁四极矩与角动量的关系呈现相似的变化趋势,推测一对h_11/2准质子可能对核芯性质起主要作用.     

Experimental Observation of High Spin States in 146Sm Nucleus

High spin states of ¹⁴⁶Sm have been experimentally studied by using ¹³C(95MeV) beam bombarding natural Ba target.Seventeen new γ-rays and eleven new levels were found and assigned to the level scheme of ¹⁴⁶Sm which extends up to 10.2MeV excitation energy.Level structure still shows the characteristics of particle configurations.No long-lived high spin isomer was found up to such high excitation region.     

129Ce高自旋态的形状变化

通过116Sn(16O,3n)Ce9Ce反应,利用多普勒移动衰减法测量了129Ce高自旋态的寿命.得到的跃迁四极矩表明129Ce的集体性相对于核芯128Ce减弱.这个因增加一个h11/2中子而引起集体性的降低可以解释为由于形状驱动效应产生三轴形变所造成的.正、负宇称带的跃迁四极矩与角动量的关系呈现相似的变化趋势,推测一对h11/2准质子可能对核芯性质起主要作用.     

~(84)Rb的高自族态研究

利用75MeV的18O束流，通过70Zn（18O，p3n）反应布居了84Rb核的高自旋态，测量了激发函数，γ－γ符合及DCO比值，新观察到了40个能级，50多条γ跃迁，建立了到目前为止最完整的能级纲图，其正负宇称分别推高到了17+和17-．通过与Rb各奇-奇同位素核和N＝47的各奇-奇核比较，发现它们的结构非常相似．     

Study on High Spin States

The high spin states of ⁸⁵Zr were populated by using fusion evaporation 60Ni (²⁸Si,2pn)⁸⁵Zr reaction. The r-r coincidence and DCO ratios were measured with 10 HPGe-BGO detectors at beam energy 102 MeV. A level scheme with 43 levels and 75 r-transitions are proposed. About 25 levels and 36 r-transitions are added to the previous work. The spin is up to 49/2+ for the yrast band. The first and second bank bandings, are observed with configurations vg9/2 π(g/2) and (vg9/2) π(g9/2) . A △I= 1 Ml band built on the 17/2- is conformed. The level structure is compared with its isotones nuclei and discussed.     

85Zr核的高自旋态研究

利用102MeV的28Si束流,通过60Ni(28Si,2pn)熔合蒸发反应布居了85Zr核的高自旋态,测量了γ-γ符合及DCO比值,建立了一个有43条能级,75条γ跃迁的能级纲图,新增加了36条γ跃迁,25条能级.将能级自旋推高到(49/2+),首次观察到了转晕带的第二回弯.并确认了一条建立在17/2-负宇称带上的磁转动带.     

Collective properties of129Cs

High-spin properties of¹²⁹Cs have been investigated following¹¹⁶Cd(¹⁸O, p4nγ) and¹²²Sn(¹¹B, 4nγ) reactions. Rotational bands built on h_11/2,g_7/2, and d_5/2 singleproton states were observed. At higher spins, band-crossings attributed to the alignment of h_11/2 neutrons were observed. A comparison with total Routhian cranking calculations support this interpretation.     

171Ta高自旋态能级寿命测量

在中国原子能科学研究院的HI 13串列加速器上通过157Gd(19F,5n)171Ta重离子熔合蒸发反应布居了171Ta的高自旋态,以多普勒移动衰减法的峰形分析法分析了171Tah9/2质子1/2[541]转动带的6条能级的寿命,得到了这6条能级的平均寿命值. The high spin states of~(171)Ta have been populated via heavy ion fusion evaporation reaction~(157)Gd(~(19)F, 5n)~(171)Ta at the HI-13 tandem accelerator in China Institute of Atomic Energy. The lifetimes of the high spin states in~(171)Ta have been measured by using the Doppler Shift Attenuation Method (DSAM). Six levels of its h_(9/2) proton 1/2\ band have been analyzed and their lifetimes have been deduced from the experimental data.     

The Semiclassical Study of Nuclear High Spin States

Nuclear high spin states are studied in the extended Thomas-Fermi approximation.Explicit formula for rotational energy and various corrections are given.Concrete calculations are performed for three typical nuclei:¹¹⁶Sn,¹⁵⁸Yb and ²⁴⁰Pu.Qualitatively,the results are similar to that of liquid drop model.Quantum corrections to rotational energy (besides shell corrections) cannot be neglected in a quantitative study.     

134Ce核的高自旋态与形状共存

在中国原子能科学研究院H13串列加速器上,通过重离子核反应¹²²Sn(¹⁶O,4n)对A=130缺中子核区的¹³⁴Ce核的高自旋态进行了研究,建立了¹³⁴Ce的新的能级纲图,最高自旋态扩展到22.然而实验结果与近期发表的134Ce核的高自旋态结果不同,所谓在¹³⁴Ce核中存在的磁转动带结构不能被实验证实.对实验结果的分析表明,¹³⁴Ce核的高自旋态结构呈现出重要的形状共存特性在基带以上的回弯处的10+态起源于两个中子组态,基于此10+态的转动带具有γ≈–60°的扁椭形变;另一个10+同质异能态为yrast陷阱,也起源于两中子组态,为具有γ≈–120°的长椭形状;而由两个signature伙伴带组成的强耦合带,则起源于h_11/2与g_7/2质子组态,为具有γ≈0°的长椭形变带.     

双奇核172Re的高自旋

对149Sm(27Al, 4n)172Re反应产生的172Re在束γ的实验数据进行了重新分析, 新发现了可归属于172Re的3个转动带, 由此建立了由6个转动带构成的172Re高自旋态能级纲图。依据相邻核的带结构知识和推转壳模型分析方法, 对新发现的3个转动带的准粒子组态进行了指定, 讨论了它们的转动特征。We have re analyzed the experimental data of in beam γ spectroscopy for 172Re via the 149Sm(27Al, 4n)172Re reaction. Three rotational bands have been newly found and assigned to 172Re. A new level scheme of 172Re, consisting of 6 bands, is thus presented. Based on the existing knowlegde from the neighboring nuclei and the cranked shell model, the quasiparticle configurtions have been assigned to the 3 newly observed bands and their structure properties have been dicussed.     

Measurement of 125Ba High Spin States

The high spin states of ¹²⁵Ba populated via the ¹⁰⁹Ag(¹⁹F,3n) reaction are measured by using a BGO Compton suppressed HPGe detector array.The negative and positive parity bands built respectively on the h_11/2 and g_7/2 neutron hole states are extended to 35/2^－ and 23/2⁺.Backbending occurs in both signature branches of the negative band at the frequencies close to that of the ¹²⁴Ba yrast band.An onset of backbending in the positive band has been seen.     

Spin Symmetry for Anti-Lambda Spectrum in Atomic Nucleus

The spin symmetry of the anti-Lambda spectrum in nucleus 16O is studied in the relativistic mean field theory. The spin-orbit splittings of spin doublets are found to be around 0.03-0.07MeV and the dominant components of the Dirac spinor for the anti-Lambda spin doublets are found to be near identical. It is indicated that there is an even better spin symmetry in the anti-Lambda spectrum than that in the anti-nucleon spectrum.     

High Spin States and Shape Coexistence in 134Ce

high spin states in ¹³⁴Ce nucleus have been studied by using the heavy–ion induced reaction ¹²²Sn(¹⁶O,4n) carried out at china institute of atomic energy. the early level scheme has been extended with spin up to 22. however,our result is different from that in a recent publication,and the magnetic rotation bands reported there have not been confirmed. our observed level structures may be interpreted as shape coexistence. the 10+ state at the backbending with h_11/2 quasineutron configuration has an oblate deformation with an asymmetry parameter γ≈–60°(lund convention),and the 10+ isomer is a yrast trap of prolate deformation with γ≈–120°,whereas the other signature partner bands with h_11/2 and g_7/2 proton configuration probably have a prolate deformation with γ≈0°.