共查询到20条相似文献,搜索用时 15 毫秒
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R. Broda P. J. Daly J. McNeill R. V. F. Janssens D. C. Radford 《Zeitschrift für Physik A Hadrons and Nuclei》1987,327(4):403-408
The level structure of theN=81 nucleus149Er has been studied by γ-ray spectroscopy following the reaction92Mo+255 MeV60Ni. Yrast levels in149Er are established up to ~3.3 MeV, including 0.61 and 4.8 μs isomeric states. Most of the observed levels are interpreted as seniority-three states arising from the coupling of s1/2, d3/2 and h11/2 neutron holes with πh 11 2/n . Isomers identified in the reaction96Ru+255 MeV58Ni are tentatively assigned to151Yb. TheB (E2) values of high-spin isomers inZ=66?70,N=81?83 nuclei are surveyed. 相似文献
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G. Winter J. Döring L. Funke L. Käubler R. Schwengner H. Prade 《Zeitschrift für Physik A Hadrons and Nuclei》1989,332(1):33-43
Using methods of in-beam spectroscopy in connection with 35 MeV7Li bombardment of82Se targets four new isomers have been identified. They are observed in83Br at 3070 keV (T1/2=0.6±0.2 μs), in85Rb at 2826 keV (T1/2=12.5±0.6 ns), in85Kr at 1991 keV (T1/2=1.2+ 0.4 1.0 μs) and in86Kr at 2250 keV (T1/2=3.1±0.6 ns). Spin and parity 19/2? have been assigned to the new isomer in85Rb that is interpreted as the coupling of a p3/2 proton to the g 9 2/?2 two-neutron excitation of the N=48 neutron system. Using the TDPAD method an upper limit for the g-factor of ¦g¦≦0.17 has been estimated for this isomer. The same two-neutron excitation is also believed to be responsible for the new isomer in83Br. The new isomers in85Kr and86Kr are interpreted as configurations containing the two-proton excitation (f 5 2/?1 , p 3 2/?1 ) where in the isomeric 17/2+ level of85Kr an additional g9/2 neutron hole is involved. 相似文献
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M. -G. Porquet A. Astier Ts. Venkova A. Prévost I. Deloncle F. Azaiez A. Buta D. Curien O. Dorvaux G. Duchêne B. J. P. Gall F. Khalfallah I. Piqueras M. Rousseau M. Meyer N. Redon O. Stézowski R. Lucas A. Bogachev 《The European Physical Journal A - Hadrons and Nuclei》2009,39(3):295-306
The 81, 82, 83, 85Se nuclei have been produced as fission fragments in the fusion reaction 18O + 208Pb at 85MeV bombarding energy and studied with the Euroball IV array. Their high-spin level schemes have been built from the
triple -ray coincidence data and - angular correlations have been analyzed in order to assign spin and parity values to many observed states. The lowest-spin
states of the two-neutron and three-neutron configurations are strongly mixed with two-proton excitations among the fp orbits. On the other hand, the highest-spin states of these neutron configurations are found to remain almost pure. Neutron
excitation across the N = 50 gap is observed both in 83Se49 and in 85Se51 . 相似文献
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S. Ganguly Aparajita Dey P. Banerjee S. Bhattacharya R. P. Singh S. Muralithar R. Kumar R. K. Bhowmik 《Brazilian Journal of Physics》2011,41(2-3):135-139
Excited states of 83Kr, populated in the 76Ge(11B, 3npγ) reaction at a beam energy of 50 MeV, have been studied. The ΔI?=?1 band, built upon the 2,510.0 keV state, has been observed up to 5,639.4 keV with spin (27/2???). Mean lifetimes have been measured up to spin 23/2?? in ΔI?=?1 band using the Doppler shift attenuation method. The B(M1) rates derived from the measured lifetimes decrease smoothly with spin indicating that the angular momentum belonging to this band are generated by the shears mechanism. 相似文献
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S. Brüssermann J. Keinonen H. P. Hellmeister K. P. Lieb 《Zeitschrift für Physik A Hadrons and Nuclei》1982,304(4):335-341
The lifetimes τ=124±12, 6 ?2 +4 and 380±100 ps of theE x (I π )=3.46(8+), 2.92(6+) and 3.04(6?) MeV states, respectively, populated by the reaction76Ge(12C,α2n) were measured with the recoil distance method. In addition upper lifetime limits were obtained for nine states. The measured lifetimes and energies indicate a band crossing at aboutI π =8+, probably arising from the alignment of twog 9/2 neutrons. For the 3.04 MeV 6? state as a second member of a band built on the 2.65 MeV 4? state the measured lifetime points to a two-quasiparticle configuration. The positive-parity states have been discussed in the frame of the interacting boson approximation, nuclear field theory and the cranked shell model. 相似文献
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L. Funke J. Döring P. Kemnitz P. Ojeda R. Schwengner E. Will G. Winter A. Johnson L. Hildingsson Th. Lindblad 《Zeitschrift für Physik A Hadrons and Nuclei》1986,323(2):127-137
Projectile and targetK-vacancy production probabilities in 4.6-, 5.8- and 7.3-MeV/a.m.u. U+U and U+Pb collisions are reported for impact parameters between 10 and 85 fm. These probability measurements are compared with available theory. 相似文献
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T.L. Khoo F.M. Bernthal C.L. Dors M. Piiparinen S. Saha P.J. Daly J. Meyer-Ter-Vehn 《Physics letters. [Part B]》1976,60(4):341-343
Positive parity levels in 191Pt obtained from (α, xnγ) reactions and β-decay are presented as a first example of a rather complete level family. The spectrum confirms triaxial shapes found before from and proton structures in this mass region. In addition to the usual decoupled yrast band, a second ΔI = 2 band within the family, built on a low-lying state, is observed in agreement with theory. 相似文献
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Valiente-Dobón JJ Steinhardt T Svensson CE Afanasjev AV Ragnarsson I Andreoiu C Austin RA Carpenter MP Dashdorj D de Angelis G Dönau F Eberth J Farnea E Freeman SJ Gadea A Garrett PE Görgen A Grinyer GF Hyland B Jenkins D Johnston-Theasby F Joshi P Jungclaus A Lieb KP Macchiavelli AO Moore EF Mukherjee G Napoli DR Phillips AA Plettner C Reviol W Sarantites D Schnare H Schumaker MA Schwengner R Seweryniak D Smith MB Stefanescu I Thelen O Wadsworth R 《Physical review letters》2005,95(23):232501
Three rotational bands in 74Kr were studied up to (in one case one transition short of) the maximum spin I(max) of their respective single-particle configurations. Their lifetimes have been determined using the Doppler-shift attenuation method. The deduced transition quadrupole moments reveal a modest decrease, but far from a complete loss of collectivity at the maximum spin I(max). This feature, together with the results of mean field calculations, indicates that the observed bands do not terminate at I = I(max). 相似文献
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潘强岩 罗亦孝 M.De Poli G.de Angelis C.Fahlander D.Bazzacco E.Farnea A.Gadea D.R.Napoli P.Spolaore 《中国物理 C》1998,22(1):1-3
利用55Mn(30Si,2p2n)反应布居了81Rb的高自旋态,GASP阵列配以由40个ΔE-ESi(Au)望远镜单元所组成的4π带电粒子球进行γγγ带电粒子(质子和α)的符合测量;实验发现了由7条级联γ跃迁所组成的81Rb高自旋超形变转动带. 其动力学惯量为J(2)=4/ΔEγ=26.7(h2/MeV),该带被解释为具有四极形变参数β2=0.51以及高N侵入组态为π51v52. 相似文献
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J. Suhonen J. Toivanen A. S. Barabash I. A. Vanushin V. I. Umatov R. Gurriarán F. Hubert Ph. Hubert 《Zeitschrift für Physik A Hadrons and Nuclei》1997,358(3):297-301
We apply the self-consistent renormalized proton-neutron QRPA (RQRPA) method to calculate the two-neutrino double beta (2νββ) decay matrix elements associated with the ground-state and excited-state transitions of the 82Se → 82Kr decay. The RQRPA method is an extension of the pnQRPA method and promotes the Pauli exclusion principle violated by the pnQRPA ground state and yields more stable nuclear matrix elements with increasing strength of the proton-neutron interaction. In the present work the RQRPA wave functions are also used to evaluate 2νββ-decay rates to excited final states. The resulting theoretical half lives are compared with the new stringent experimental limits obtained by using a HPGe detector and external sources of enriched selenium. 相似文献
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A mean lifetime of τ = 35 ± 3 ps of the 2+1 state in 76Kr has been measured with the recoil distance method via the reaction 63Cu(19F, α2n)76Kr. The B(E2; 0+1 → 2+1) values and lifetimes of the 2+1 states in 82, 84Kr have been measured via Coulomb excitation using the 1.4 MeV/A UNILAC krypton beams. The intensities of the γ-rays from the Coulomb excited levels of 82, 84Kr were interrelated with those of the target nuclei 27Al, 64, 66Zn and 70, 72, 74, 76Ge and yielded the values , respectively. In turn, these B(E2) values and the (E2; 0+1 → 2+1 values of the even Ge and Zn isotopes from the literature were used in a Doppler-shift attenuation analysis to obtain experimentally lacking electronic stopping power for Kr ions slowing down in Al, Zn and Ge. for Ge ions in Ge and for Zn ions in Zn. 相似文献
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Mössbauer spectroscopy of the 9.4 keV transition in83Kr has been performed using sources of83Rb implanted in the group IV semiconductors diamond, silicon, germanium and tin and in the metals Cu, Ag, Au, Mo and W. From the line widths and isomer shifts information has been obtained on possible lattice sites of the impurities. In most cases a site with large isomer shift, thought to correspond to a compression of the krypton atom was observed. This site is interpreted to represent purely substitutional impurities. In Mo and W a well-defined vacancy release stage was observed, leading to a reduction of the isomer shift and a line broadening. 相似文献
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A quasi-rotational band built on the known proton four-hole, two-particle 0+ level at 1473.07-keV in114Cd has been identified, with 2+, 4+, and 6+ members at 1783.44-, 2250.53- and 2876.75-keV respectively. These levels and their properties are compared with those in other even-mass Cd nuclei to show an increasing average deformation in both the 0 1 + (ground-state) and 0 2 + bands when neutron pairs are added beyond110Cd. 相似文献
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Albers M Warr N Nomura K Blazhev A Jolie J Mücher D Bastin B Bauer C Bernards C Bettermann L Bildstein V Butterworth J Cappellazzo M Cederkäll J Cline D Darby I Das Gupta S Daugas JM Davinson T De Witte H Diriken J Filipescu D Fiori E Fransen C Gaffney LP Georgiev G Gernhäuser R Hackstein M Heinze S Hess H Huyse M Jenkins D Konki J Kowalczyk M Kröll T Krücken R Litzinger J Lutter R Marginean N Mihai C Moschner K Napiorkowski P Singh BS Nowak K Otsuka T Pakarinen J Pfeiffer M Radeck D Reiter P 《Physical review letters》2012,108(6):062701
The neutron-rich nuclei 94,96Kr were studied via projectile Coulomb excitation at the REX-ISOLDE facility at CERN. Level energies of the first excited 2(+) states and their absolute E2 transition strengths to the ground state are determined and discussed in the context of the E(2(1)(+)) and B(E2;2(1)(+)→0(1)(+)) systematics of the krypton chain. Contrary to previously published results no sudden onset of deformation is observed. This experimental result is supported by a new proton-neutron interacting boson model calculation based on the constrained Hartree-Fock-Bogoliubov approach using the microscopic Gogny-D1M energy density functional. 相似文献
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The structure of 81Kr has been investigated via the 80Kr(d?, p)81Kr reaction using an 11.0 MeV vector-polarized deuteron beam. Differential cross sections σ and vector analyzing powers Ay have been measured from 20° to 90° for 17 excited states below 3.0 MeV excitation energy. Comparisons of these distributions to DWBA calculations and empirical shapes were made to extract spectroscopic factors and values of spin and parity for these states. The significance of these measurements to the design of a bromine solar neutrino detector is discussed. 相似文献
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High-spin states in 81Rb were populated in the 55Mn(30Si, 2p2n) reaction at 130 MeV. Prompt γγγ-charged particle coincidences were observed using the GASP spectrometer in conjunction with the ΔE-E silicon ball (ISIS). A superdeformed band consisting of seven γ-ray transitions has been identified. The dynamic moment of inertia for the band is constant with a value of approximately 26.7 h2/MeV throughout the whole observed rotational frequency. This band is interpreted to have a π51v52 intrinsic intruder configuration with a quadruple deformation β2 of 0.51. 相似文献
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S. Verma R. Devi S. K. Khosa 《The European Physical Journal A - Hadrons and Nuclei》2006,30(3):531-539
The yrast spectra of 78-82Kr are studied by using the projected shell model (PSM) approach. The energy states are obtained by taking oblate as well
as prolate quadrupole deformations for 78-82Kr. The structure of yrast states and backbending phenomena are investigated. The theoretical results predict low-lying states
in 78, 82Kr to be oblate and coexistence of oblate-prolate shapes for 80Kr. The B(E2) transition probabilities and g-factors are obtained and compared with the available experimental data. 相似文献