共查询到20条相似文献,搜索用时 31 毫秒
1.
J.H. Hamilton A.V. Ramayya J.K. Hwang X.Y. Luo J.O. Rasmussen E.F. Jones X.Q. Zhang S.J. Zhu P.M. Gore T.N. Ginter I.Y. Lee R.V.F. Janssens I. Ahmed J.D. Cole W. Greiner G. Ter-Akopian Yu. Oganessian 《The European Physical Journal A - Hadrons and Nuclei》2002,15(1-2):175-179
With new high statistic data, new isotopes and new high-spin structures are observed in neutron-rich nuclei populated in the
spontaneous fission of 252Cf. The 135Te levels are extended, and many new levels in 139,141Ba observed. The coexistence of collective and single particle-hole states is found in 135Te. The N = 83 135Te and 139Ba show marked differences associated with differences in their particle and hole states. New levels in 141Ba complete evidence for two opposite-parity doublets characteristic of stable octupole deformation. In 114,116Pd a second backbend is observed for the first time in this mass region and the backbend in 118Pd occurs earlier than in 112-116Pd because of a reduction in pairing. Gamma-type vibrational bands are seen up to 13+ to 15+ in 104,106Mo, 108-112Ru, and 112-116Pd. Their behavior reflects prolate to triaxial shapes in these nuclei. The levels of 162,164Gd are observed for the first time. As N increases toward mid-shell at 104, the moments of inertia in N = 100 164Gd show an unexpected decrease compared to N = 98 162Gd. The levels in 162,164Gd form remarkable shifted identical bands with nuclei separated by 2n, 2p, α, and 2α.
Received: 21 March 2002 / Accepted: 16 May 2002 / Published online: 31 October 2002
RID="a"
ID="a"e-mail: j.h.hamilton@vanderbilt.edu 相似文献
2.
W. Urban N. Schulz M. Bentaleb E. Lubkiewicz J. L. Durell M. J. Leddy M. A. Jones W. R. Phillips A. G. Smith B. J. Varley I. Ahmad L. R. Morss 《The European Physical Journal A - Hadrons and Nuclei》2000,8(1):5-7
Excited levels in 141Xe, populated in spontaneous fission of 248Cm, were studied by means of prompt -ray spectroscopy, using the EUROGAMM2 array. Level scheme of 141Xe obtained in this work shows patterns characteristic of simplex symmetry with s=+i and s=-i bands present but low value of D0 moment indicates that octupole correlations in Xe isotopes are systematically lower than in Ba nuclei.
Received: 9 March 2000 / Accepted: 4 May 2000 相似文献
3.
E. Mergel C.M. Petrache G. Lo Bianco H. Hübel J. Domscheit D. Roßbach G. Schönwaßer N. Nenoff A. Neußer A. Görgen F. Becker E. Bouchez M. Houry A. Hürstel Y. Le Coz R. Lucas Ch. Theisen W. Korten A. Bracco N. Blasi F. Camera S. Leoni F. Hannachi A. Lopez-Martens M. Rejmund D. Gassmann P. Reiter P.G. Thirolf A. Astier N. Buforn M. Meyer N. Redon O. Stezowski 《The European Physical Journal A - Hadrons and Nuclei》2002,15(4):417-420
The even-even nucleus 136Nd was studied via in-beam γ-ray spectroscopy using the 16O + 125Te reaction at 100 MeV and the EUROBALL array. One new dipole band was observed. Together with a previously identified dipole
band, whose position in the level scheme is revised, the new band forms a doublet structure similar to the recently observed
chiral bands in the odd-odd neighboring nuclei. This would be the first case of a chiral doublet in an even-even nucleus.
Received: 23 May 2002 / Accepted: 30 September 2002 / Published online: 27 November 2002
RID="a"
ID="a"e-mail: costel.petrache@unicam.it
RID="b"
ID="b"Present address: Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
RID="c"
ID="c"Present address: Gesellschaft für Schwerionenforschung D-64291 Darmstadt, Germany.
Communicated by C. Signorini 相似文献
4.
M.-G. Porquet Ts. Venkova P. Petkov A. Bauchet I. Deloncle A. Astier N. Buforn J. Duprat B.J.P. Gall C. Gautherin E. Gueorguieva F. Hoellinger T. Kutsarova R. Lucas M. Meyer A. Minkova N. Redon N. Schulz H. Sergolle A. Wilson 《The European Physical Journal A - Hadrons and Nuclei》2002,15(4):463-470
The 106, 108Rh and 110, 112Ag nuclei have been produced as fission fragments following the fusion reaction 28Si + 176Yb at 145 MeV bombarding energy and studied with the Eurogam2 array. The yrast high-spin states of these four odd-odd nuclei,
which are observed for the first time, consist of rotational bands in which the odd proton occupies the πg
9/2 subshell and the odd neutron the νh
11/2 subshell. Their behaviour as a function of spin values does not vary with the number of neutrons: as observed in the odd-N neighbouring nuclei, the motion of the odd neutron remains decoupled from the motion of the core, from N = 61 to N = 65. Moreover, the staggering observed in the yrast bands of odd-odd isotopes is strongly reduced as compared to the large
values displayed by the rotational bands built on the πg
9/2 subshell in the odd-A Rh and Ag isotopes. The results of particle-rotor calculations indicate that this reduction is related to a change of the
core deformation.
Received: 1 June 2001 / Accepted: 23 July 2002 / Published online: 10 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: NAC, Faure, ZA 7131, South Africa.
RID="d"
ID="d"Present address: Department of Nuclear Physics, ANU, Canberra ACT 0200, Australia.
Communicated by D. Schwalm 相似文献
5.
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
6.
R. Lucas M.-G. Porquet Ts. Venkova I. Deloncle M. Houry Ch. Theisen A. Astier A. Bauchet S. Lalkovski G. Barreau N. Buforn T.P. Doan L. Donadille O. Dorvaux J. Durell Th. Ethvignot B.P.J. Gall D. Grimwood W. Korten Y. Le Coz M. Meyer A. Minkova A. Prévost N. Redon A. Roach N. Schulz A.G. Smith O. Stézowski B.J. Varley 《The European Physical Journal A - Hadrons and Nuclei》2002,15(3):315-323
The 115, 117, 119, 121In nuclei have been produced as fission fragments in three reactions induced by heavy ions: 12C + 238U at 90MeV bombarding energy, 18O + 208Pb reaction at 85MeV, and 31P + 176Yb at 152MeV. Their level schemes have been built from gamma-rays detected using the EUROBALL III and IV arrays. High-spin
states of 117, 119, 121In nuclei have been identified for the first time. Moreover, isomeric states lying around 2.5MeV have been established in
119, 121In from the delayed coincidences between the fission fragment detector SAPhIR and the gamma array. Most of the observed states
can be described by coupling a proton g
9/2 hole to a Sn core, while the intruder band based on an orbital from the π[g
7/2/d
5/2] sub-shells behaves as the ground-state band of neighbouring Cd isotopes.
Received: 24 May 2002 / Accepted: 11 June 2002 / Published online: 19 November 2002
RID="a"
ID="a"e-mail: porquet@csnsm.in2p3.fr
RID="b"
ID="b"Present address: CEA-DIF, DAM/DCRE/SDE/LDN, 91680 Bruyères-le-Chatel, France.
RID="c"
ID="c"Present address: CSNSM IN2P3-CNRS and Université Paris-Sud 91405 Orsay, France.
RID="d"
ID="d"Present address: CEA/Saclay, DSM/DAPNIA/SPhN, 91191 Gif-sur-Yvette Cedex, France.
Communicated by D. Schwalm 相似文献
7.
8.
T. Bäck B. Cederwall K. Lagergren R. Wyss A. Johnson P. Greenlees D. Jenkins P. Jones D.T. Joss R. Julin S. Juutinen A. Keenan H. Kettunen P. Kuusiniemi M. Leino A.-P. Leppänen M. Muikku P. Nieminen J. Pakarinen P. Rahkila J. Uusitalo 《The European Physical Journal A - Hadrons and Nuclei》2003,17(1):1-5
The decay out of the πh
11/2νh
11/2 band to the known low-energy levels in 132La was studied using the reaction 100Mo + 36S at 160 MeV beam energy. The low-energy level scheme has been further developed and unambiguous spin and parity values have
been assigned to the levels connecting the band to the 6- isomeric state. According to the new level scheme the spins in the πh
11/2νh
11/2 band are shifted up by one unit compared to the earlier tentative experimental values. The obtained new spins prove the existence
of signature inversion in 132La and give further support to the spin assignments made for the πh
11/2νh
11/2 bands in the neighbouring odd-odd La isotopes from level energy systematics.
Received: 7 May 2002 / Accepted: 31 October 2002 / Published online: 17 January 2003
RID="a"
ID="a"e-mail: timar@atomki.hu
RID="b"
ID="b"Present address: Dipartimento di Matematica e Fisica, Università di Camerino, via Madonna delle Carceri, I-62032 Camerino, Italy.
Communicated by J. ?yst? 相似文献
9.
A. Neußer H. Hübel G.B. Hagemann S. Bhattacharya P. Bringel D. Curien O. Dorvaux J. Domscheit F. Hannachi D.R. Jensen A. Lopez-Martens E. Mergel N. Nenoff A.K. Singh 《The European Physical Journal A - Hadrons and Nuclei》2002,15(4):439-441
First evidence is presented for triaxial superdeformation in 170Hf. High-spin states in this nucleus have been investigated in a γ-ray coincidence measurement using the EUROBALL spectrometer
array. A new band was discovered which has moments of inertia that are very similar to the ones of triaxial superdeformed
bands in neighbouring Hf and Lu nuclei. The intensities with which these bands are populated are different from what may be
expected from calculated potential-energy minima.
Received: 11 September 2002 / Accepted: 15 October 2002 / Published online: 10 December 2002
RID="a"
ID="a"e-mail: neusser@iskp.uni-bonn.de
Communicated by D. Schwalm 相似文献
10.
P. Egelhof G.D. Alkhazov M.N. Andronenko A. Bauchet A.V. Dobrovolsky S. Fritz G.E. Gavrilov H. Geissel C. Gross A.V. Khanzadeev G.A. Korolev G. Kraus A.A. Lobodenko G. Münzenberg M. Mutterer S.R. Neumaier T. Schäfer C. Scheidenberger D.M. Seliverstov N.A. Timofeev A.A. Vorobyov V.I. Yatsoura 《The European Physical Journal A - Hadrons and Nuclei》2002,15(1-2):27-33
Proton-nucleus elastic scattering at intermediate energies, a well-established method for probing nuclear-matter density distributions
of stable nuclei, was applied for the first time to exotic nuclei. This method is demonstrated to be an effective means for
obtaining accurate and detailed information on the size and radial shape of halo nuclei. Absolute differential cross-sections
for small-angle scattering were measured at energies near 700 MeV/u for the neutron-rich helium isotopes 6He and 8He, and more recently for the lithium isotopes 6Li, 8Li, 9Li and 11Li, using He and Li beams provided by the fragment separator FRS at GSI Darmstadt. Experiments were performed in inverse kinematics
using the hydrogen-filled ionization chamber IKAR which served simultaneously as target and recoil-proton detector. For deducing
nuclear-matter distributions, differential cross-sections calculated with the aid of the Glauber multiple-scattering theory,
using various parametrizations for the nucleon density distributions as input, were fitted to the experimental cross-sections.
The results on nuclear-matter radii and matter distributions are presented, and the significance of the data for a halo structure
is discussed. Nuclear-matter distributions obtained for 6He and 8He conform with the concept that both nuclei compose of α-particle like cores and significant neutron halos. The matter distribution
in 11Li exhibits, as expected from previous reaction cross-section studies with nuclear targets, the by far most extended halo
component of all nuclei being investigated. In addition the present data allow a quantitative comparison of the structure
of the He and Li isobares of either the mass number A = 6 or A = 8. The measured differential cross-sections have also been used for probing density distributions as predicted from various
microscopic calculations. A few examples are presented.
Received: 21 March 2002 / Accepted: 16 May 2002 / Published online: 31 October 2002
RID="a"
ID="a"e-mail: p.egelhof@gsi.de 相似文献
11.
A. Hürstel M. Rejmund E. Bouchez P.T. Greenlees K. Hauschild S. Juutinen H. Kettunen W. Korten Y. Le Coz P. Nieminen Ch. Theisen A.N. Andreyev F. Becker T. Enqvist P.M. Jones R. Julin H. Kankaanpää A. Keenan P. Kuusiniemi M. Leino A.-P. Leppänen M. Muikku J. Pakarinen P. Rahkila J. Uusitalo 《The European Physical Journal A - Hadrons and Nuclei》2002,15(3):329-334
Prompt and delayed gamma-ray spectroscopy of very neutron-deficient bismuth isotopes 187, 189Bi has been performed using the Recoil Decay Tagging (RTD) method. The isomeric i
13/2 states have been identified and their lifetimes have been measured. The systematics of these long-lived M2 isomers has been extended to the proton-unbound isotopes. The general behaviour of single-proton states is discussed within
the systematics and interpreted within the shell-model framework.
Received: 2 May 2002 / Accepted: 3 June 2002 / Published online: 19 November 2002
RID="a"
ID="a"e-mail: wkorten@cea.fr
RID="b"
ID="b"Present address: GANIL, Caen, France.
RID="c"
ID="c"Present address: Radiation and Nuclear Safety Authority, P.O. Box 14, FIN-00881 Helsinki.
Communicated by D. Schwalm 相似文献
12.
W. Urban J.A. Pinston T. Rzaca-Urban A. Złomaniec G. Simpson J.L. Durell W.R. Phillips A.G. Smith B.J. Varley I. Ahmad N. Schulz 《The European Physical Journal A - Hadrons and Nuclei》2003,16(1):11-15
A new band, populated by the spontaneous fission of 248Cm and studied by means of prompt γ-ray spectroscopy using the EUROGAM2 array, was observed in 99Zr. The 1038.8 keV band head with a half-life T
1/2 = 54(10) ns is interpreted as a K-isomer, corresponding to the 9/2[404] neutron-hole excitation. It is the first observation of this orbital in the mass A ∼ 100 region. The quadrupole moment, Q
0 = 3.9(3) eb deduced for the new band indicates a large deformation of β = 0.41, which is produced by a specific shape-coexistence
mechanism, known in other regions and now found in the A ∼ 100 nuclei.
Received: 11 September 2002 / Accepted: 31 October 2002 / Published online: 17 January 2003
RID="a"
ID="a"e-mail: urban@fuw.edu.pl
Communicated by D. Schwalm 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.
O. Sorlin C. Donzaud F. Nowacki J.C. Angélique F. Azaiez C. Bourgeois V. Chiste Z. Dlouhy S. Grévy D. Guillemaud-Mueller F. Ibrahim K.-L Kratz M. Lewitowicz S.M. Lukyanov J. Mrasek Yu.-E. Penionzhkevich F. de Oliveira Santos B. Pfeiffer F. Pougheon A. Poves M.G. Saint-Laurent M. Stanoiu 《The European Physical Journal A - Hadrons and Nuclei》2003,16(1):55-61
The neutron-rich nuclei 23
60-63V have been produced at GANIL via interactions of a 61.8A·MeV 76Ge beam with a 58Ni target. Beta-decay to 24
60-63Cr has been investigated using combined β- and γ-ray spectroscopy. Half-lives of the 60-63V nuclei have been determined, and the existence of a beta-decay isomer in the 60V nucleus is strongly supported. The observation of low-energy 2+ states in 60Cr (646keV) and 62Cr (446keV) suggests that these isotopes are strongly deformed with β2 ∼ 0.3. This is confirmed by shell model calculations which show the dominant influence of the intruder g and d orbitals to obtain low 2+ energies in the neutron-rich Cr isotopes.
Received: 13 June 2002 / Accepted: 27 August 2002 / Published online: 17 January 2003
RID="a"
ID="a"e-mail: sorlin@ipno.in2p3.fr
Communicated by D. Guerreau 相似文献
15.
H. Kettunen T. Enqvist M. Leino K. Eskola P.T. Greenlees K. Helariutta P. Jones R. Julin S. Juutinen H. Kankaanpää H. Koivisto P. Kuusiniemi M. Muikku P. Nieminen P. Rahkila J. Uusitalo 《The European Physical Journal A - Hadrons and Nuclei》2003,16(4):457-467
The low-energy nuclear structure and decay properties of the neutron-deficient isotopes 195At and 191Bi have been studied. 195At was produced in the reaction 142Nd(56Fe,p2n)195At and 191Bi as the daughter activity of 195At. The activities were implanted in a position-sensitive silicon detector after being separated from the primary beam by
a gas-filled recoil separator. The 1/2+ intruder state was determined to be the ground state in 195At with an alpha-decay energy of E
α = 6953(3) keV and a half-life T
1/2 = 328(20) ms. Another state with an alpha-decay energy E
α = 7075(4) keV and a half-life T
1/2 = 147(5) ms was found to decay to a 148.7(5) keV excited state in 191Bi for which a spin and parity of 7/2- were deduced. Consequently, the same 7/2- character was assigned to the initial state at 32(7) keV in 195At on the basis of unhindered alpha-decay. The 9/2- state, being the ground state in heavier odd-mass astatine isotopes, was not observed.
Received: 16 September 2002 / Accepted: 19 December 2002 / Published online: 25 March 2003
RID="a"
ID="a"e-mail: heikki.kettunen@phys.jyu.fi
RID="b"
ID="b"Present address: Laboratory of Radiochemistry, P.O. Box 55, FIN-00014, University of Helsinki, Finland.
RID="c"
ID="c"Present address: Radiation and Nuclear Safety Authority, P.O. Box 14, FIN-00881 Helsinki, Finland.
Communicated by W. Henning 相似文献
16.
T. Hayakawa Y. Toh M. Oshima M. Matsuda Y. Hatsukawa J. Katakura H. Iimura T. Shizuma S. Mitarai M. Sugawara H. Kusakari Y.H. Zhang 《The European Physical Journal A - Hadrons and Nuclei》2002,15(3):299-302
High-spin states of 157Dy were investigated using in-beam γ-ray spectroscopy techniques with a 150Nd(12C, 5n) reaction. Three rotational bands with the h
9/2, i
13/2 and h
11/2 configurations were observed up to (43/2-), 53/2+ and 45/2-, respectively. Interband M1 transitions in the h
11/2 (high-Ω) band were also measured up to the highest-spin state. The high-spin states were well reproduced by calculations
using the tilted-axis-cranking model (TAC). The B(M1)/B(E2) ratio, Routhian and the tilted angle of the angular-momentum vector are found to be in good agreement with the result of
the TAC calculation.
Received: 22 August 2002 / Accepted: 26 September 2002 / Published online: 19 November 2002
RID="a"
ID="a"e-mail: hayakawa@jball4.tokai.jaeri.go.jp
Communicated by W. Henning 相似文献
17.
F. Azaiez M. Belleguic D. Sohler M. Stanoiu Zs. Dombrádi O. Sorlin J. Timár F. Amorini D. Baiborodin A. Bauchet F. Becker C. Borcea C. Bourgeois Z. Dlouhy C. Donzaud J. Duprat D. Guillemaud-Mueller F. Ibrahim M.J. Lopez R. Lucas S.M. Lukyanov V. Maslov J. Mrazek C. Moore F. Nowacki B.M. Nyakó Yu.-E. Penionzhkevich M.G. Saint-Laurent F. Sarazin J.A. Scarpaci G. Sletten C. Stodel M. Taylor C. Theisen G. Voltolini 《The European Physical Journal A - Hadrons and Nuclei》2002,15(1-2):93-97
The structure of neutron-rich light nuclei around N = 20 and 28 has been investigated at GANIL by means of in-beam gamma-spectroscopy using fragmentation reactions of 36S and 48Ca beams on a Be target. Gamma-decay of relatively high-lying excited states have been measured for the first time in nuclei
around 32Mg and 44S. Level schemes are proposed and discussed for a large number of these neutron-rich nuclei around N = 20 and N = 28.
Received: 21 March 2002 / Accepted: 16 May 2002 / Published online: 31 October 2002
RID="a"
ID="a"e-mail: azaiez@ipno.in2p3.fr 相似文献
18.
H. Mahmud C.N. Davids P.J. Woods T. Davinson A. Heinz J.J. Ressler K. Schmidt D. Seweryniak J. Shergur A.A. Sonzogni W.B. Walters 《The European Physical Journal A - Hadrons and Nuclei》2002,15(1-2):85-87
78Kr beams were used to bombard 58Ni, 92Mo and 96Ru, producing three new, odd-odd, proton-emitting isotopes, 130Eu, 164mIr and 170Au. Preliminary experimental and theoretical results will be presented in this paper.
Received: 21 March 2002 / Accepted: 16 May 2002 / Published online: 31 October 2002
RID="a"
ID="a"e-mail: mahmud@ph.ed.ac.uk 相似文献
19.
P. Bringel H. Hübel H. Amro M. Axiotis D. Bazzacco S. Bhattacharya R. Bhowmik J. Domscheit G.B. Hagemann D.R. Jensen Th. Kröll S. Lunardi D.R. Napoli A. Neußer S.C. Pancholi C.M. Petrache G. Schönwaßer A.K. Singh C. Ur 《The European Physical Journal A - Hadrons and Nuclei》2003,16(2):155-158
High-spin states in 161Lu and 162Lu have been investigated using the GASP γ-ray spectrometer array. Excited states in these nuclei have been populated through
the 100Mo(65Cu, xn) reaction at a beam energy of 260 MeV. Four presumably triaxial superdeformed bands, three in 162Lu and one in 161Lu, have been observed. This is the first evidence for triaxial superdeformation in the two isotopes.
Received: 18 October 2002 / Accepted: 21 November 2002 / Published online: 4 February 2003
RID="a"
ID="a"e-mail: bringel@iskp.uni-bonn.de
RID="b"
ID="b"Present address: Wright Nuclear Structure Laboratory, Yale University, New Haven, CT 06520, USA.
RID="c"
ID="c"Present address: Physik Department, Technische Universit?t München, James Franck Str., D-85748 Garching, Germany.
Communicated by D. Schwalm 相似文献
20.
M. Bentaleb N. Schulz E. Lubkiewicz J. L. Durell C. J. Pearson W. R. Phillips J. Shannon B. J. Varley I. Ahmad C. J. Lister L. R. Morss K. L. Nash C. W. Williams 《Zeitschrift für Physik A Hadrons and Nuclei》1996,354(1):143-151
A search for octupole deformation in neutron-rich Xe isotopes has been conducted through prompt gammaray spectroscopy of secondary fragments produced in the spontaneous fission of248Cm. The spectrometer consisted of the Eurogam 1 array and a set of 5 LEPS detectors. Level schemes were constructed for Xe isotopes with mass number ranging from 140 to 144 and excited states for143,144Xe nuclei were observed for the first time. None of the level schemes exhibit an alternating parity quasimolecular band, a feature usually expected in nuclei in which octupole correlation effects are strong enough to produce stable octupole deformation. For several isotopes, structures observed in the level schemes are consistent with an octupole softness of the nuclei. 相似文献