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《Nuclear Physics A》1988,476(1):99-106
The population of high-spin yrast and near yrast states of 1347Gd and the associated multiplicity of feeding transitions have been studied in the 124Sn (28Si, 5n) reaction at 139, 146 and 152 MeV. The yrast feeding is found to be independent of the initial angular momentum distribution and very weak for states of spin greater than 30 ħ. The average multiplicity of γ-transitions is found to increase with increasing beam energy. The experimental results are interpreted in terms of collective excitations within rotational bands that channel the γ- decay towards the known oblate single-particle yrast states below ~30 ħ. 相似文献
3.
ZHU ShengJiang GAN CuiYun ZHU LingYan YANG LiMing XU RuiQing JON MyonGil JIANG Zhuo ZHANG Zheng 《中国物理C(英文版)》2000,24(11):1018-1023
Through study of the prompt r-rays emitted in the spontaneous fission of 252Cf, high spin states of neutron-rich odd-A 145,147Ce nuclei have been investigated. The levels in 147Ce have been extended. A collective band in 145Ce have been identified for the first time. The results from the particle rotor model calculations indicate that the yrast bands in 145Ce and 147Ce originate from vi13/2 orbital coupling and the ground states of 145Ce and 147Ce originate from (vh9/2,vf7/2) and vh9/2 configiration, respectively. No obvious octupole deformation was observed in these two isotopes, but a side band obtained in 147Ce may show some octupole correlations. 相似文献
4.
LI Guang-Sheng YANG Li-Ming DAI Zheng-Yu LIU Xiang-An ZHANG Lan-Kuan WEN Shu-Xian WU Xiao-Guang YUAN Guan-Jun WENG Pei-Kun LI Sheng-Gang ZHU Sheng-Jiang YANG Chun-Xiang 《中国物理C(英文版)》2002,26(8):809-813
Lifetimes of the excited states in light rare-earth nucleus 130Ce have been measured using heavy ion reaction 116Sn(16O,2n)130Ce at beam energy of 73MeV through analyzing the Doppler-broadened line shapes. The reduced transition probabilities B(E2) are extracted from these measurements. The experimental results show that the previously reported anomalously high B(E2) value has not been observed in the present work. The transition quadrupole moment for the yrast band varies with spin and corresponds to a triaxial deformation with γ≈7°. 相似文献
5.
ZHU Sheng-Jiang GAN Cui-Yun ZHU Ling-Yan YANG Li-Ming LONG Gui-Lu WUN Shu-Xian WU Xiao-Guang LI Guang-Sheng ZHU Li-Hua 《中国物理C(英文版)》2005,29(2):130-138
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 h11/2 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 h11/2 and g7/2 proton configuration probably have a prolate deformation with γ≈0°. 相似文献
6.
XIAO Shu-Dong ZHU Sheng-Jiang YANG Li-Ming ZHANG Zheng JIANG Zhuo CHE Xing-Lai U Yong-Nan 《中国物理C(英文版)》2004,28(1):37-41
High spin states in neutron-rich 116,118,120Cd nuclei have been investigated by observing high-fold prompt γ-ray coincidence events from the spontaneous fission of 252Cf with the Gammasphere detector array. The yrast bands have been extended with spin up to 18h in118Cd and 16h in 116,120Cd respectively. The band structures are calculated using the cranked shell model and possible origination for the backbends in the yrast bands is discussed. Proposed 5- and 7- levels are observed in each of these cadmium isotopes, and possible explanation for the negative states is discussed based on systematic comparison. A quasi-rotational band based on 7- level in 118Cd has been established. 相似文献
7.
Z. Liu Y.H. Zhang X.H. Zhou M.L. Liu W.J. Luo Q.Y. Pan Z.G. Gan T. Hayakawa M. Oshima Y. Toh T. Shizima Y. Hatsukawa A. Osa T. Ishii M. Sugawara 《The European Physical Journal A - Hadrons and Nuclei》2002,13(3):277-280
Excited states of 142Ce, populated in deep inelastic reactions of 82Se projectiles bombarding 139La target, have been studied up to medium spins using in-beam γ spectroscopy techniques. Three new levels have been identified
at 2625, 2995, 3834 keV, and assigned as 8+, 9(-) and 11(-), respectively. These new yrast states follow closely the level systematics of the even mass N = 84 isotones. Their strctures have been discussed with the help of empirical shell model calculations.
Received: 2 November 2001 / Accepted: 15 January 2002 相似文献
8.
Ts. Venkova M. -G. Porquet A. Astier I. Deloncle P. Petkov A. Prévost F. Azaiez A. Bogachev A. Buta D. Curien O. Dorvaux G. Duchêne J. Durell B. J. P. Gall M. Houry F. Khalfallah R. Lucas M. Meyer I. Piqueras N. Redon A. Roach M. Rousseau O. Stézowski Ch. Theisen 《The European Physical Journal A - Hadrons and Nuclei》2005,26(3):315-319
High-spin states of the N = 87 nuclei, 147Nd and 145Ce, have been populated in the 12C + 238U and 18O + 208Pb fusion-fission reactions at 90 MeV and 85 MeV bombarding energy, respectively. The emitted γ-radiation was detected using
the Euroball III and IV arrays. High-spin states of the 147Nd isotope have been identified for the first time. The high-spin yrast and near-to-yrast structures of the 145Ce nucleus have been considerably extended. The newly observed structures, discussed by analogy with the neighbouring isotones,
show the coupling of an h9/2 neutron to the quadrupole and octupole excitations of the core. 相似文献
9.
CHEN Yong-Jing ZHU Sheng-Jiang CHE Xin-Lai DING Huai-Bo LI Ming-Liang 《中国物理C(英文版)》2006,30(8):740-744
High-spin structures in 146Ce nucleus have been re-investigated by measuring the prompt γ rays from spontaneous fission of 252Cf. The previously reported level scheme of 146Ce has been updated. The octupole deformed collective bands have been extended up to higher spin states. A possible quasi-γ band structure was examined and reconstructed according to our data analysis. In addition, the reflection asymmetric shell model was applied to describe the octupole deformed bands in 146Ce, and the calculated results are in good agreement with the experimental data at lower spins. 相似文献
10.
In the present work, the structures of the excited positive/negative-parity yrast states of 101Tc are discussed by using a projected shell model, and a band diagram calculated for the positive-parity yrast band is also shown in order to extract physics out of numerical results. In addition, the analysis of other three bands originated from 3/2-[301], 5/2-[303], and 1/2+[431] Nilsson states, respectively, is also performed in the framework of this model. Until recently, very little property about the N=52—54 intermediate nuclei in the Z~42—44 region has been known. In order to understand these "transitional nuclei", we select the nucleus 95Tc as an example. So in this work, we also present our investigation of the level structure in the 95Tc nucleus. 相似文献
11.
刘忠 张玉虎 郭应祥 周小红 雷相国 柳敏良 罗万居 何建军 郑勇 潘强岩 甘再国 罗亦孝 T.Hayakawa M.Oshima Y.Toh T.Shizima Y.Hatsukawa A.Osa T.Ishii M.Sugawara 《中国物理 C》2002,26(10):1015-1020
利用420MeV82Se轰击139La引起的深部非弹反应和在束γ谱学方法研究了142Ce的中高自旋激发态.识别出了激发能为2625,2995和3834keV的3个新能级,自旋、宇称分别被指定为8+,9(-)和11(-).发现这些能级非常好地符合N=84偶偶核转晕能级的系统性.利用经验壳模型计算了142Ce的中高自旋激发态的激发能,计算结果比较好地重现了实验值.对它们的结构进行了讨论,表明在142Ce的中高自旋激发态中以单粒子激发为主 相似文献
12.
M. Müller-Veggian K. Zuber H. Güven G. de Angelis J. Styczen M. Lach G. Hebbinghaus P. Kleinheinz 《Zeitschrift für Physik A Hadrons and Nuclei》1988,330(3):343-344
An in-beam γ-ray study with the144Sm (α, p4n) reaction has established the high-spin states up to 5 MeV excitation and I=35/2 in the N=80 nucleus143Eu. The observed yrast states show the typical irregular pattern of a spherical nucleus, with frequent decay branchings and often dominant dipole de-excitation. The level spectrum is in qualitative accord with the coupling of the h11/2 proton particle to the known yrast levels of the142Sm core nucleus. Only in a few cases specific configuration assignments are made. 相似文献
13.
Yrast and near-yrast states have been investigated in 210Rn to high spin (J > 30) and high energy (Ex > 10 MeV). Three different (HI, xn) reactions were used to populate the states of interest and several different γ-ray spectroscopic techniques were utilized. Three high-spin yrast traps were discovered. Two de-excite by strong E3 transitions while the third decays mainly via an extremely inhibited E2 transition. The E3 decays are interpreted as allowed single-particle transitions between proton or neutron states above the 208Pb shell closure while the inhibited E2 transition is interpreted as indicating a substantial change in structure as the decay proceeds down the yrast line. The interpretation has been given in terms of shell-model calculations. 相似文献
14.
The time development of oxygen-induced compound reactions on 27Al and 58Ni targets at 30–70 MeV beam energy has been calculated in the framework of the statistical model. Feeding times associated with the population of yrast states in the evaporation residues have been estimated. It is shown that the experimental feeding times τ1 < 0.2 ps, when combined with measured evaporation residue cross sections and/or absolute γ-ray yields, put restrictions on the spin dependence of the level density. Furthermore, it has been found that the dipole strength of continuum transitions between high-spin states is of the same order of magnitude as that obtained in radiative neutron capture reactions. 相似文献
15.
E. Ideguchi X.H. Zhou Y. Gono S. Mitarai T. Morikawa M. Kidera H. Tsuchida M. Shibata H. Watanabe M. Miyake A. Odahara M. Oshima Y. Hatsukawa S. Hamada H. Iimura M. Shibata T. Ishi T. Kishida M. Ishihara 《The European Physical Journal A - Hadrons and Nuclei》1999,6(4):387-390
High spin states of 146Eu were studied by in-beam gamma ray spectroscopic techniques using 140Ce(10B,4n)146Eu and 139La(13C,6n)146Eu reactions. The level scheme was established up to 10MeV. A new high spin isomer with 10ns half life was found. Configurations
of yrast states were understood by a weak coupling of f7/2 neutron to those of 145Eu.
Received: 2 November 1999 相似文献
16.
S. Lunardi F. Soramel W. Starzecki W. Meczynski R. Julin M. Lach A. Ercan P. Kleinheinz 《Zeitschrift für Physik A Hadrons and Nuclei》1986,324(4):433-437
Excitation function measurements with α-particles and HI-beams clearly attribute the yrast cascade previously proposed for142Gd to the141Eu neighbouring nucleus. The so far unknown yrast transitions of142Gd have been identified. Coincidence measurements establish the high-spin level schemes of the two nuclei up to 3.2 MeV. 相似文献
17.
《Nuclear Physics A》1987,466(2):385-418
High-spin states in 162Tm and 164Tm have been studied by 152,154Sm(14N, 4n) reactions. Measurements of γ-rays, angular distributions and γγ-coincidences were performed using Ge detectors. In each isotope, two side bands are observed besides the yrast band, which are followed up to high-spin states. An interpretation of the experimental results is proposed in the framework of the cranked shell-model. Results on gyromagnetic ratios in the yrast band of a series of odd-N Tm nuclei are presented. Magnetic properties of the side bands are also discussed. 相似文献
18.
SUN Xiang-Fu YU Jian-Fang GUO Ying-Xiang LEI Xiang-Guo LUO Yi-Xiao WANG Ji-Cheng XU Xiao-Ji WEN Shu-Xian WENG Pei-Kun LI Sheng-Gang YANG Chun-Xiang 《中国物理C(英文版)》1992,16(1):62-67
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 h11/2 and g7/2 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. 相似文献
19.
《Nuclear Physics A》1999,645(2):191-202
The time evolution of the decay of high-spin, normal deformed structures in 193,194Hg was studied by measuring, in the Gammasphere array, the Doppler shift attenuation of selected transitions depopulating various bands. The data suggest that a fraction of states feeding selective yrast levels is non-collective in nature and show resemblance to A = 150 nuclei where shape polarizing effects have been linked to particles occupying high-j orbitals. 相似文献
20.
B. Haas D. Ward H.R. Andrews O. Hausser A.J. Ferguson J.F. Sharpey-Schafer T.K. Alexander W. Trautmann D. Horn P. Taras P. Skensved T.L. Khoo R.K. Smither I. Ahmad C.N. Davids W. Kutschera S. Levenson C.L. Dors 《Nuclear Physics A》1981,362(1):254-300
We have studied level schemes for the feeding and decay of high-spin isomers in the nuclei 148, 149, 151, 152Dy and 147 Gd. A variety of techniques involving γ-ray spectroscopy with pulsed heavy-ion beams have been applied including linear polarization, γ-γ correlations and recoil distance measurements.The general aspect of these level schemes is in accordance with the idea that the states near and along the yrast line can be described by a spheroidal shell model in which the nucleus is axially symmetric with respect to the total spin. In these cases the spin is generated not by collective rotation, but by alignment of many single-particle orbits around a common axis. 相似文献