共查询到20条相似文献,搜索用时 967 毫秒
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骆鹏 柳敏良 刘忠 张玉虎 周小红 郭应祥 马英君 Y.Sasaki K.Yamada H.Ohshima S.Yokose M.Ishizuka T.Komatsubara K.Furuno 《中国物理 C》2004,28(3):268-273
利用在束γ谱学技术,通过128Te(10B,1p3n)134Ba反应研究了134Ba的中、高自旋激发态.实验中采用9套BGO(AC)HPGe探测器进行了γγt符合测量.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134Ba的能级纲图.比较N=78的同中子素链的负宇称能级结构的系统性,发现激发能位于4142keV,Jπ值为11-的能级很可能是与136Ce具有相似内禀结构特征的相似态 相似文献
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146Tb的能级结构研究 总被引:1,自引:0,他引:1
利用能量为161—175MeV的32S束流,通过反应118Sn(32S,1p3n)146Tb研究了双奇核146Tb的高自旋态能级结构. 实验进行了γ射线的激发函数、γ射线的各向异性度、X–γ和γ–γ–t符合测量. 基于这些测量结果,建立了激发能达8390kev的146Tb核的能级纲图,其中包括新发现的41条γ射线和新建立的27个能级,并指定了146Tb新发现能级的自旋值. 用一个h11/2价质子和一个h11/2-1价中子空穴耦合、πh11/2υh11/2-1与146Gd核实激发态的耦合对146Tb的能级结构进行了定性地讨论. 相似文献
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本文用扩散型光学位阱对低能(中子2—4兆电子伏,质子3.5—7兆电子伏)非弹性散射角分布、激发函数和γ射线角分布进行了计算,目的是比较系统地定量检验Hauser-Feshbach理论。计算结果和实验符合得很好。说明H.F.理论中的基本出发点,即不同复合核态之间的干涉相消的假设,是近似成立的。在此基础上,我们进一步讨论了可以用H.F.公式来提供光学位阱参数与能级自旋宇称知识的可能性,后者具体应用至N14的高激发态,计算表明:N14的4.91兆电子伏和5.01兆电子伏能级的自旋分别为0和2,能级的自旋对截面的大小影响很显著,但宇称则几乎没有影响。同时我们也应用H.F.理论讨论了相邻奇-偶核和偶-偶核弹性散射的差异。最后,考虑到同位旋在轻核中是一个准守恆量,本文中研究了在复合核过程中同位旋守恆的可能性,给出了考虑同位旋守恆以后的H.F.公式。并对于N14(p,p′)N14*至第一激发态2.31兆电子伏(t=1),和第二激发态3.95兆电子伏(t=0)的非弹性散射角分布,分别在同位旋守恒和不守恒情况下进行了计算,结果表明,不守恒时的计算值和现有的实验非常接近,看来同位旋量子数在轻核的复合核反应中守恆性是很差的。 相似文献
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朱胜江 陈智超 E.F.Zganjar M.O.Kortelahti J. L.Wood H.K.Carter J.H.Hamilton A.V.Ramayya X.Zhao 《中国物理 C》1994,18(3):193-201
利用177Hf(19F,9n)187T1反应和在线同位素分离法,对187Au低激发态能级结构进行了γ–γ符合与γ–e符合的测量分析,束流能量为175MeV,发现了多条新的跃迁,测量了内转换系数,扩展了187Au的能级图.对187Au低激发态下的集体带结构、单质子与不同偶–偶核芯的耦合特性进行了讨论. 相似文献
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张玉虎柳敏良 G.de Angelis Zs.Podolyak 郭文涛 A.Gadea C.Ur N.Marginean C.Rusu R.Schwengner D.R.Napoli R.Menegazzo S.Lunardi D.Bazzacco< 《中国物理 C》2004,28(9):941-946
通过重离子融合蒸发反应16O(82Se+4n)94Mo布局了94Mo核的高自旋态.利用多探头探测器阵列GASP进行了在束γ测量,从而重新研究了94Mo核的高自旋态能级结构.基于新发现的一些重要的连接跃迁,对94Mo核的高自旋态能级纲图做了重要修改.将新的能级结构与壳模型计算进行了比较和讨论.结果表明要正确的描述94?Mo核的高自旋态(自旋值大于14)能级结构,应考虑价中子在d5/2,g7/2和h11/2轨道上的激发. 相似文献
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A. Astier P. Petkov M. -G. Porquet D. S. Delion P. Schuck 《The European Physical Journal A - Hadrons and Nuclei》2010,46(2):165-185
Excited states in 212Po have been populated by a \alpha transfer using the 208Pb(18O,14C) reaction at 85MeV beam energy and studied with the EUROBALL IV g \gamma multi-detector array. The level scheme has been extended up to ∼ 3.2 MeV excitation energy from the triple-g \gamma coincidence data. Spin and parity values of most of the observed states have been assigned from the g \gamma angular distributions and g \gamma -g \gamma angular correlations. Several g \gamma -lines with E
γ
< 1 MeV have been found to be shifted by the Doppler effect, allowing for the measurements of the associated lifetimes by
the DSAM method. The values, found in the range [0.1-0.6]ps, lead to very enhanced E1 transitions. All the emitting states, which have non-natural parity values, are discussed in terms of a \alpha - 208Pb structure. They are in the same excitation-energy range as the states issued from shell-model configurations. 相似文献
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E. Ott M. Schimmer R. Wirowski H. Wolters I. Jansen A. von der Werth A. Dewald P. von Brentano 《Zeitschrift für Physik A Hadrons and Nuclei》1994,348(1):57-58
High spin states of144Sm have been investigated via the126Te(24Mg,4n) reaction at 98 MeV with in-beam- ray spectroscopy using the Compton-suppressed germanium detector array OSIRIS-CUBE. 44 new levels and 82 new transitions have been placed in the level scheme. Spins up to J=18 were assigned from gamma angular distribution data and parities were determined from gamma linear polarization data obtained using the POLALI spectrometer. The experimentally observed excitation energies of negative parity states could be well reproduced by shell model calculations. 相似文献
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The levels in124Te have been investigated by studying the gamma rays emitted following the decay of 60d124Sb. Gamma-gamma coincidence spectra have been taken with gates set at 603, 646, 709, 714 and 723 keV gamma rays by using 105 cm3 Ge(Li)-110 cm3 HPGe coincidence system. 69 gamma rays have been observed and nine of them are reported for the first time. Four new levels in124Te at 2512, 2550.2, 2808 and 2814.5 keV are proposed. Levels reported in literatures at 2412 and 2733 keV are excluded from the level scheme of124Te based on the present study. The experimentally determined energy spectrum of low-lying positive parity states, B(E2) ratios and electric quadrupole moment of the first excited state are compared with the IBM-1 predictions. 相似文献
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Ajimura S Hayakawa H Kishimoto T Kohri H Matsuoka K Minami S Mori T Morikubo K Saji E Sakaguchi A Shimizu Y Sumihama M Chrien RE May M Pile P Rusek A Sutter R Eugenio P Franklin G Khaustov P Paschke K Quinn BP Schumacher RA Franz J Fukuda T Noumi H Outa H Gan L Tang L Yuan L Tamura H Nakano J Tamagawa T Tanida K Sawafta R 《Physical review letters》2001,86(19):4255-4258
The spin-orbit splitting of Lambda single-particle states in (13)(Lambda)C was measured. The 13C(K-,pi(-))(13)(Lambda)C reaction was used to excite both the 1/2(-) and 3/2(-) states simultaneously, which have predominantly 12C(0(+)) x p(Lambda) configuration. gamma rays from the states to the ground state were measured in coincidence with the pi(-)'s, by which ls splitting was found to be 152+/-54(stat)+/-36(syst) keV. The value is 20-30 times smaller than exhibited by the ls splitting in the nuclear shell model. This value gives us new insight into the YN interaction. 相似文献
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We report about two new rigorous results on the nonanalytic properties of thermodynamic potentials at first-order phase transition. For lattice models (d>or=2) with arbitrary finite state space, finite-range interactions which have two ground states, we prove that the pressure has no analytic continuation at the first-order phase-transition point, under the only further assumptions that the Peierls condition is satisfied for the ground states and that the temperature is sufficiently low. For Ising models with Kac potentials J(gamma)(x)=gamma(d)phi(gammax), where 00) and analyticity in the mean field limit (gamma SE pointing arrow 0). 相似文献
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Boutachkov P Rogachev GV Goldberg VZ Aprahamian A Becchetti FD Bychowski JP Chen Y Chubarian G DeYoung PA Kolata JJ Lamm LO Peaslee GF Quinn M Skorodumov BB Wöhr A 《Physical review letters》2005,95(13):132502
We have developed a new technique to study exotic neutron-rich nuclei via their isobaric analog states (IAS). We populate high-isospin states in resonant reactions of radioactive ion beams with protons. Characteristic gamma rays emitted from excited decay products were used to identify the population of the IAS. We show that information on the differential and total cross section for formation of the IAS can be extracted from the energy spectrum of the Doppler-shifted gamma rays. This technique was applied to the study of T=3/2 states in 7Li, which are analogs of states in 7He. The analog of the 7He ground state was clearly observed, whereas the presence of the analog of a narrow 1/2(-) state at 0.6 MeV excitation in 7He reported by M. Meister et al. [Phys. Rev. Lett. 88, 102501 (2002)] was excluded at the 90% confidence level. Evidence is presented for a broad 1/2(-) state at a higher excitation energy in 7He. 相似文献
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Zhang GP 《Physical review letters》2001,86(10):2086-2089
Neither pure Mott insulators nor pure charge-transfer insulators have ever been considered as a possible candidate for nonlinear optical (NLO) materials since individually neither the strong correlation (U) nor the large charge transfer (Delta) is favorable to the NLO response. However, in their composites, charge-transfer-Mott insulators, jointly Delta and U can enhance the hyperpolarizability (gamma) by guiding the ground states into the antiferromagnetic phase and the excited states into the charge-transfer phase. These Delta and U that maximize gamma form a unique golden Delta-U line, on which the recently observed giant nonlinear optical effect is just a single point, whose physical origin is that the system is driven into a phase-separated region for the ground and excited states. This novel mechanism may suggest a conceptually new paradigm to explore an even larger optical nonlinearity. 相似文献
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在偶-偶核基态中寻找稳定的三轴形状,其中最大三轴形变为|γ|≈30°,仍然是核结构的一个主要主题。在本工作中,使用推转Woods-Saxon(WS)壳模型来研究Os-Pt区基态和集体转动态中可能的三轴形状。为寻找核态可能存在的三轴形变,具体用对力-形变-转动频率自洽推转壳模型对偶-偶176-202Os和182-204Pt同位素进行了总Routhian面计算。计算是在四极形变(β2,γ)网格中进行的,而十六极形变β4可变。事实上,在四极形变(β2,γ)的每个网格点上,计算的能量相对于十六极形变β4最小化。发现某些核的基态譬如196Os和188-194Pt既非扁椭球亦非长椭球,而是在这些核中基态极小值是形状非轴对称的,即三轴形变。同时,我们把从实验数据提取出的转动惯量与我们的计算结果作比较,显示实验数据不能很好地与转动假定相一致,说明有振动行为。此外,我们使用一种辅助的方法提取了平衡γ0值,该值... 相似文献
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T. W. Conlon 《Nuclear Physics A》1967,100(3):545-573
Eight new isomeric states with half-lives in the range 10 μs-30 ms have been identified following bombardment with 17.5 MeV protons of the natural elements and separated isotopes of the elements Eu to Pb. Improved data on 14, previously reported, isomeric states have also been obtained. The energies, half-lives and multipolarities of the gamma rays from these states have been measured using an 8 cm3 Ge(Li) detector. In most cases, level schemes have been constructed, and the spin and parity of the isomeric level and intermediate levels populated in the decay have been determined. A group of hindered E2 transitions have been observed, all of which are retarded by approximately the same degree e.g. 3 × 10−3 Weisskopf units. The results are discussed in terms of the Nilsson model and in terms of the selection rules for transitions between Nilsson states. 相似文献
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Csorna SE Danko I McLean KW Xu Z Godang R Bonvicini G Cinabro D Dubrovin M McGee S Zhou GJ Bornheim A Lipeles E Pappas SP Schmidtler M Shapiro A Sun WM Weinstein AJ Jaffe DE Masek G Paar HP Asner DM Eppich A Hill TS Morrison RJ Briere RA Chen GP Ferguson T Vogel H Gritsan A Alexander JP Baker R Bebek C Berger BE Berkelman K Blanc F Boisvert V Cassel DG Drell PS Duboscq JE Ecklund KM Ehrlich R Foland AD Gaidarev P Galik RS Gibbons L Gittelman B Gray SW Hartill DL Heltsley BK Hopman PI Hsu L 《Physical review letters》2001,86(19):4243-4246
Using 13.7 fb(-1) of data recorded by the CLEO detector at Cornell Electron Storage Ring, we report evidence of two new charmed baryons: one decaying into Xi(0')(c)pi(+) with the subsequent decay Xi(0')(c)-->Xi(0)(c)gamma, and its isospin partner decaying into Xi(+')(c)pi(-) followed by Xi(+')(c)-->Xi(+)(c)gamma. We measure the following mass differences for the two states: M(Xi(0)(c)gammapi(+))-M(Xi(0)(c)) = 318.2+/-1.3+/-2.9 MeV and M(Xi(+)(c)gammapi(-))-M(Xi(+)(c)) = 324.0+/-1.3+/-3.0 MeV. We interpret these new states as the J(P) = 1 / 2(-) Xi(c1) particles, the charmed-strange analogs of the Lambda(+)(c1)(2593). 相似文献