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1.
C.-B. Moon T. Komatsubara T. Shizuma Y. Sasaki H. Ishiyama T. Jumatsu K. Furuno 《The European Physical Journal A - Hadrons and Nuclei》1999,5(1):13-16
High-spin states in 117I have been studied via the 103Rh(18O, 4n) reaction at a beam energy of 85 MeV. Many deformed rotational bands built on the proton h11/2, g7/2, and g9/2 orbitals have been identified. Among them, an unfavoured rotational band and a quasi-gamma band based on the h11/2 state have been newly observed. Moreover, positive-parity states above Iπ= 35/2+ reported in the previous work have been rearranged. Several energetically favoured states have been assigned to noncollective
oblate states based on various quasiparticle configurations with β2≈ 0.18–0.19 and γ= 60°.
Received: 1 March 1999 相似文献
2.
Ts. Venkova M.-G. Porquet I. Deloncle B.J.P. Gall H. De Witte P. Petkov A. Bauchet T. Kutsarova E. Gueorgieva J. Duprat C. Gautherin F. Hoellinger R. Lucas A. Minkova N. Schulz H. Sergolle E.A. Stefanova A. Wilson 《The European Physical Journal A - Hadrons and Nuclei》1999,6(4):405-413
The 107,109Rh nuclei have been produced as fission fragments following the fusion reaction 28Si +176Yb at 145 MeV bombarding energy and studied with the Eurogam2 array. In both nuclei three new rotational bands with the odd
proton occupying the πg9/2, πp1/2 and π(g7/2/d5/2) sub-shells have been observed. In 107Rh, two other bands involving strong M1 transitions have been identified at excitation energy larger than 2 MeV. They can
be interpreted in terms of three quasiparticle excitations. In addition new structures consisting of four transitions, built
on states located at low excitation energy (680 keV in 107Rh and 642 keV in 109Rh), point out the importance of triaxial deformation in these two isotopes.
Received: 1 September 1999 相似文献
3.
Z. Liu X. Sun X. Zhou X. Lei Y. Guo Y. Zhang X. Chen H. Jin Y. Luo S.X. Wen C.X. Yang G.J. Yuan G.S. Li X.A. Liu W.D. Luo Y.S. Chen 《The European Physical Journal A - Hadrons and Nuclei》1998,1(2):125-135
High-spin states of 117Xe were investigated by means of in-beam γ-ray spectroscopic techniques via the reaction of 28Si bombarding a 92Mo target at beam energies of 100-120 MeV. A positive-parity rotational band decaying into the yrast negative-parity band
by a series of enhanced E1 transitions was observed for the first time, implying the existence of octupole correlations in
117Xe. The B(E1) values increase with spin. The νd5/2 band was firmly established up to 27/2+ and the B(M1)/B(E2) ratios were extracted from the relative intensities of γ-rays in this band. The previously known νh11/2 and νg7/2 [413]5/2+α=−1/2 bands were confirmed and extended up to high spins and two bandcrossings are observed in the latter at ħω=0.33 and
0.44 MeV, respectively. The bandcrossings and configurations of these bands are discussed by TRS and CSM calculations. In
a γ–γ–t measurement, the 11/2− and 7/2− levels were identified as two isomers with half-lives of 59.4±20 ns and 16.5±8.0 ns, respectively.
Received: 17 June 1997 / Revised version: 29 September 1997 相似文献
4.
N. Buforn A. Astier J. Meyer M. Meyer S. Perriès N. Redon O. Stézowski M.G. Porquet I. Deloncle A. Bauchet J. Duprat B.J.P. Gall C. Gautherin E. Gueorguieva F. Hoellinger T. Kutsarova R. Lucas A. Minkova N. Schulz H. Sergolle Ts. Venkova A.N. Wilson 《The European Physical Journal A - Hadrons and Nuclei》2000,7(3):347-353
High-spin states in 113-116Cd have been investigated with the fusion-fission reaction 28Si +176Yb at 145 > MeV. The experiment has been performed with the Eurogam2 array. New rotational bands based on two quasi-particle
states have been observed for even-even cadmium isotopes. A new level scheme based on the 11/2− isomeric state is proposed for 115Cd and the one of 113Cd has been extended to spin (31/2−). The decoupled bands identified in both odd-A nuclei are interpreted as being built upon a low-Ωh11/2 quasi-neutron configuration. Microscopic Hartree-Fock + BCS calculations confirm the prolate deformation in this mass region
especially for the odd cadmium isotopes.
Received: 21 December 1999 / Revised version: 16 February 2000 相似文献
5.
T.R. Saitoh N. Hashimoto G. Sletten R.A. Bark S. Törmänen M. Bergström K. Furuno K. Furutaka G.B. Hagemann T. Hayakawa T. Komatsubara A. Maj S. Mitarai M. Oshima J. Sampson T. Shizuma P.G. Varmette 《The European Physical Journal A - Hadrons and Nuclei》1998,3(3):197-199
High-spin states in 181Ta have been studied via the 176Yb(11B,α2n) reaction at 52 MeV using the PEX array and at 57 MeV using the NORDBALL array, with α-particle detection. The previously
known, Kπ=(7/2)+ ground state band and Kπ=(9/2)− band have been extended to spins (29/2)+ and (31/2)−, respectively. Two new one-quasiparticle bands, the Kπ=(5/2)+ band built on the known (5/2)+ isomer and a Kπ=((1/2)−) band have been observed. Two other rotational bands with three-quasiparticle structure, Kπ=(15/2)− and ((19/2)+ with π(7/2)[404]ν2(1/2)[510](9/2)[624] and π(9/2)[514]ν2(1/2)[510](9/2)[624] configurations, respectively, have been newly observed. The half-life of the Kπ=((19/2)+) bandhead which decays to the head of the (15/2)− band has been measured to be 140(36) ns. However, transitions from the ((19/2)+) state to the (15/2)− band have not been observed.
Received: 26 August 1998 相似文献
6.
R.P. Singh R.K. Bhowmik S.S. Ghugre S.B. Patel 《The European Physical Journal A - Hadrons and Nuclei》2000,7(1):35-40
High spins states in 99Rh were populated via the 66Zn(37Cl, 2p2n)99Rh reaction at an incident beam energy of 130 MeV. Seventeen new transitions have been observed in the present study and the
level scheme has now been extended up to a spin of J∼ 25ħ and an excitation energy of about E
x∼ 10 MeV. The observation of a positive parity E2 cascade based on the 9/2+ isomeric level is suggestive of collective behaviour in this nucleus up to high spins. Spherical shell model (within restricted
model space) and Cranked shell model calculations were performed to obtain an insight into the observed level structure. The
new collective band observed up to a spin of J∼ 25ħ is suggested to be based on (πg
9/2
3) ⊗ (νg
7/2
2) quasi-particle excitations.
Received: 12 July 1999 / Revised version: 14 September 1999 相似文献
7.
A.M. El-Badry T. Kuroyanagi S. Mitarai A. Odahara Y. Gono S. Morinobu K. Ogawa 《The European Physical Journal A - Hadrons and Nuclei》1998,3(2):133-138
A recoil distance method was used to measure half-lives of the excited states of 145Sm. The reaction used was 139La(10B, 4n)145Sm. A plunger system was used. Half-lives were determined for two excited states for the first time. The yrast 27/2+ state was found to have a half-life of 1.1 ± 0.2 ns corresponding to the retardation of 3.1 × 10−4 comparing with the single particle estimate of M1. The excitation energy of this state was well reproduced by the shell model
calculation having a mixed configuration of [π{h11/2(g7/2)−2 (d5/2)−1}10−, νf7/2] + [π{h11/2(g7/2)−1}9−,νh9/2]. Another retarded E1 transition was also found in a decay of a 21/2+ state. Its retardation was 1.6 × 10−4 comparing with the single particle value.
Received: 9 September 1997 / Revised version: 12 June 1998 相似文献
8.
P. Bhattacharyya C.T. Zhang P.J. Daly B. Fornal Z.W. Grabowski I. Ahmad T. Lauritsen L.R. Morss W. Urban A. Nowak W.R. Phillips J.L. Durell M.J. Leddy A.G. Smith B.J. Varley N. Schulz E. Lubkiewicz M. Bentaleb J. Blomqvist 《The European Physical Journal A - Hadrons and Nuclei》1998,3(2):109-110
By analysis of fission product γ-ray data measured at Eurogam II using a 248Cm source, yrast levels up to about 2 MeV in the N=84 three-particle nucleus 135Sb have been identified. These levels are interpreted as π g7/2ν f7/2
2 and π g7/2ν f7/2h9/2 states with the help of shell model calculations using empirical nucleon-nucleon interactions.
Received: 30 July 1998 相似文献
9.
J. Timár A. Gizon P. Paris J. Genevey J. Gizon F. Hannachi C.F. Liang A. Lopez-Martens J.C. Merdinger B.M. Nyakó B. Weiss L. Zolnai 《The European Physical Journal A - Hadrons and Nuclei》2000,7(1):7-10
High spin states of 126La have been populated using the reaction 116Sn+14N at 68 MeV. γ-rays and conversion electrons were detected with the GAREL array. Multipolarities of the lowest-lying in-band
dipole transitions have been determined from the deduced internal conversion coefficients. Experimental B(M1)/B(E2) ratios
have been derived for the bands and compared with calculated values using the D?nau-Frauendorf geometrical model. Configurations
are proposed for the bands comparing them with cranked shell model calculations and on the basis of the measured B(M1)/B(E2)
ratios. The β-decay of 126La has also been revisited. The population of the 126Ba levels gives a probable spin value of five for the decaying high-spin 126La state with T
1/2≈ 64 s which may indicate a signature inversion in the πh11/2νh11/2 band.
Received: 12 October 1999 相似文献
10.
Y.H. Zhang S.Q. Zhang W.X. Huang X.H. Zhou X.C. Feng X. Xu X.G. Lei Y.X. Guo S.F. Zhu J.J. He Z. Liu S.J. Wang Y.X. Luo 《The European Physical Journal A - Hadrons and Nuclei》2000,7(1):19-22
An effort has been made to search for the decoupled bands in odd-odd 174Re via the 159Tb(20Ne,5n γ)174Re reaction through excitation functions, K x-γ and γ-γ coincidence measurements. The doubly decoupled band and the semidecoupled
one have been found in this work. Their quasiparticle configurations are proposed to be π1/2−[541] ⊗ν1/2−[521] and π1/2−[541] ⊗νi
13/2, respectively, according to the characteristics of band structures in this mass region. Another band with strongly coupled
character is also reported.
Received: 23 November 1999 / Revised version: 5 January 2000 相似文献
11.
Y.H. Zhang M. Oshima Y. Toh M. Koizumi A. Osa T. Shizuma T. Hayakawa M. Sugawara H. Kusakari T. Morikawa S.X. Wen L.H. Zhu 《The European Physical Journal A - Hadrons and Nuclei》2002,13(4):429-433
The 109,111,113Rh nuclei have been produced as fission fragments in the fusion reaction 18O + 208Pb at 85 MeV. Their level schemes have been built from gamma-rays detected using the Euroball IV array. High-spin states of
the neutron-rich 111,113Rh nuclei have been identified for the first time. Several rotational bands with the odd proton occupying the πg
9/2, πp
1/2 and π(g
7/2/d
5/2) sub-shells have been observed. A band of low-energy transitions has been identified at excitation energy around 2 MeV in
109,111Rh, which can be interpreted in terms of three-quasiparticle excitation, πg
9/2νh
11/2νg
7/2/d
5/2. In addition another structure built on states located at low excitation energy (608 keV in 111Rh, 570 keV in 113Rh) points out that, as already observed in the lighter isotopes 107,109Rh, triaxial deformation plays a role in the neutron-rich Rh isotopes well beyond the mid-shell.
Received: 15 July 2002 / Accepted: 9 October 2002 / Published online: 3 December 2002
RID="a"
ID="a"e-mail: porquet@csnsm.in2p3.fr
RID="b"
ID="b"Present address: CSNSM IN2P3-CNRS and Université Paris-Sud 91405 Orsay, France.
RID="c"
ID="c"Present address: CEA/Saclay, DSM/DAPNIA/SPhN, 91191 Gif-sur-Yvette Cedex, France.
Communicated by D. Schwalm 相似文献
12.
T. Bäck B. Cederwall R. Wyss A. Johnson J. Cederkäll M. Devlin J. Elson D.R. LaFosse F. Lerma D.G. Sarantites R.M. Clark P. Fallon I.Y. Lee A.O. Macchiavelli R.W. Macleod 《The European Physical Journal A - Hadrons and Nuclei》1999,6(4):391-397
High-spin states in 88Mo were studied using the Gammasphere germanium detector array in conjunction with the Microball CsI(Tl) charged-particle
detector system. Three γ-ray cascades with dynamic moments of inertia showing similar characteristics to superdeformed rotational
bands observed in the neighbouring A= 80 region have been identified and assigned to the nucleus 88Mo. The quadrupole moment of the strongest band, deduced by the Residual Doppler Shift Method, corresponds to a quadrupole
deformation of β2≈ 0.6. This confirms the superdeformed nature of this band. The experimental data are interpreted in the framework of total
routhian surface calculations. All three bands are assigned to two-quasi-particle proton configurations at superdeformed shape.
Received: 20 May 1999 / Revised version: 25 August 1999 相似文献
13.
The configuration-dependent cranked Nilsson-Strutinsky approach has been employed to study the properties and band structures
at high spin in the Z = N odd-odd nuclei 46V and 50Mn. The observed bands are explained and terminating states are confirmed by the calculations. The calculated and observed
bands are in good agreement without normalization, especially for terminating states. Possible bands with rotation around
the intermediate axis and the effect of γ-deformation on the total energy of several interesting configurations are discussed.
Received: 2 April 2002 / Accepted: 27 January 2003 / Published online: 15 April 2003 相似文献
14.
J. Mrázek M. Honusek A. Špalek J. Bielčík J. Slívová J. Adam A.A. Pasternak 《The European Physical Journal A - Hadrons and Nuclei》1999,5(4):399-408
The results of in-beam investigations of excited states of 99Ru using the 98Mo(α,3n) reaction are presented. Angular distributions of γ–rays and γ–γ coincidences have been measured. Excited states have
been identified up to an energy of E = 5603 keV and spin of Iπ= 31/2−. Mean lifetimes τ have been determined using the DSA method for eleven levels. Aligned angular momenta are discussed and
the probable (νh
11/2) origin of a backbending at frequency about 0.5 MeV was confirmed. The possible role of (νd
5/2) alignment at frequencies above 0.5 MeV was pointed out.
Received: 13 January 1999 / Revised version: 26 March 1999 相似文献
15.
E.S. Paul A.J. Boston S. Courtin P.J. Dagnall J.L. Durell C. Finck B. Gall B. Haas F. Haas F. Hannachi F. Hoellinger J.C. Lisle A. Lopez-Martens J.C. Merdinger N. Rowley H.C. Scraggs O. Stezowski B.J. Varley J.P. Vivien 《The European Physical Journal A - Hadrons and Nuclei》2000,7(4):449-450
The low-spin band structure of neutron-deficient 115
54Xe has been studied following a low-energy (212.3 MeV) 60Ni(58Ni,2pnγ) reaction performed at IReS, Strasbourg, with the Garel+ spectrometer. The relative excitation energies of νh11/2 (isomeric), νg7/2, and νd5/2 bandheads have been established.
Received: 23 March 2000 相似文献
16.
J.Y. Huh C.S. Lee Y.K. Kwon J.Y. Kim Y. Gono T. Morikawa H. Watanabe M. Shibata S. Motomura T. Tsutsumi T. Fukuchi T. Kishida E. Ideguchi X.H. Zhou A. Odahara S. Kubono J.H. Ha M.K. Cheoun C. Lee J.C. Kim C.-B. Moon S.J. Chae Y.K. Kim J.S. Chai 《The European Physical Journal A - Hadrons and Nuclei》2000,7(1):11-14
High-spin states of 155Gd were populated by using the 154Sm(α,3nγ)155Gd reaction at E
α= 33 MeV. γ-γ coincidence, E
γ singles, excitation function, and the DCO ratios were measured. we have identified three intermediate bands with ΔI= 2 feeding the positive yrast band. The bands are interpreted as such candidate bands that are mixed with the negative-parity
ground state band. This observation can provide a plausible explanation for unusually large population of the positive-parity
yrast band observed in a recent Coulomb excitation.
Received: 2 November 1999 相似文献
17.
N. Buforn A. Astier R. Duffait M. Meyer S. Perriès A. Prévost N. Redon O. Stézowski A. Goergen H. Hübel E. Mergel S. Neumann D. Rossbach N. Nenoff G. Schoenwasser A. Bauchet I. Deloncle M.G. Porquet A.N. Wilson R. Lucas F.A. Beck D. Curien G. Duchêne B.J.P. Gall N. Kintz J.P. Vivien D.M. Cullen 《The European Physical Journal A - Hadrons and Nuclei》2000,9(1):29-34
This work has established eight cross-talk transitions between the two signature partner superdeformed (SD) bands in 197Pb with the EUROBALL IV spectrometer. Directional correlations from oriented states measurements confirm the ΔI = 1 character of these transitions. The flat behaviour of the dynamical moment of inertia and the agreement between the experimental
and microscopic HF+BCS values of (g
K - g
R)K/Q
0 suggest that the configuration of the SD bands is based upon the υ[752]5/2- neutron intruder orbital. The derived effective spin gyromagnetic factor g
s
eff is found to be not quenched, and is close to the theoretical g
s
free value.
Received: 14 June 2000 / Accepted: 14 September 2000 相似文献
18.
C. S. Lee J. H. Ha J. H. Lee J. Y. Huh J. C. Kim C. -B. Moon S. J. Chae T. Komatsubara T. Shizuma H. Kimura K. Matsuura K. Kato Y. Sasaki H. Ishiyama K. Furuno 《The European Physical Journal A - Hadrons and Nuclei》2000,8(1):1-3
High-Spin states of odd-odd 166Lu were populated using the 139La(30Si,3nγ)166Lu at a beam energy of 120 MeV. Twelve new γ-rays were placed on top of the previously known two rotational bands built upon πg
7/2⊗νi
13/2 and πh
11/2⊗νi
13/2. Extending high-spin states up to 21+ and 25− for each band, we have observed the onset of band crossing near ħω
c ≈ 0.35 MeV. The band crossing frequency of the yrast πh
11/2⊗νi
13/2 band is consistent with the neutron BC band crossing observed in lighter odd-odd Lu isotopes. 相似文献
19.
G.D. Jones P.A. Butler T.H. Hoare P.M. Jones 《The European Physical Journal A - Hadrons and Nuclei》1998,2(2):129-141
The low spin states of 223Ra have been populated via α-decay from 227Th which was itself produced following β− decay of an 227Ac source. α–γ and α−e
K,L,M angular correlation measurements have been analysed using the correct ground state spins of 227Th(=1/2+) and 223Ra(=3/2+) for the first time.
The analysis has allowed unique Jπ values to be assigned to almost all levels below 400 keV excitation in 223Ra.
Values of (g
K−g
R)/Q
0 have been deduced for several members of the K= 3/2± bands (for the first time in an odd N nucleus in this mass region) allowing estimates of g
K and g
R to be extracted. The values of g
K and g
R are not significantly different for the positive and negative parity band members and tend to support other strong evidence
that stable octupole deformation exists in 223Ra at low excitation energies.
Received: 17 November 1997 / Revised version: 8 January 1998 相似文献
20.
T. Hayakawa M. Oshima Y. Hatsukawa J. Katakura H. Iimura M. Matsuda N. Shinohara Y. Toh S. Mitarai T. Shizuma M. Sugawara H. Kusakari 《The European Physical Journal A - Hadrons and Nuclei》2000,9(2):153-156
The in-beam spectroscopy on N = 91 isotones has been carried out using the 12C + 150Nd reaction. The νi
13/2 and νh
11/2 bands of 153Sm have been extended up to 33/2+ and 31/2-, respectively. Two new γ-rays have been located on the top of the unfavored band with νi
13/2 configuration in 157Dy. Two identical relationships have been established in the low-spin region of the yrast νi
13/2 configuration between 153Sm and 155Gd, and between unfavored bands of 155Gd and 157Dy. Here all these nuclei have the same neutron number N = 91.
Received: 28 June 2000 / Accepted: 20 October 2000 相似文献