共查询到20条相似文献,搜索用时 15 毫秒
1.
W. Urban T. Rzaca-Urban N. Schulz J.L. Durell W.R. Phillips A.G. Smith B.J. Varley I. Ahmad 《The European Physical Journal A - Hadrons and Nuclei》2003,16(3):303-307
Excited levels in 140Xe and 142Xe nuclei, populated in the spontaneous fission of 248Cm, were studied by means of prompt γ-ray spectroscopy, using EUROGAM2 array. We report the first observation of an octupole
band in 142Xe and extend the octupole band in 140Xe. Level schemes of 140Xe and 142Xe obtained in this work show patterns characteristic of ocupole-vibrational bands. Properties of octupole bands in Xe isotopes
indicate that octupole correlations in these nuclei are lower than in the corresponding Ba nuclei. The electric dipole moment
of 142Xe was found to be larger than in other Xe isotopes, contrary to theoretical predictions. This may be due to the special role
of the N = 88 neutron number.
Received: 18 November 2002 / Accepted: 15 December 2002 / Published online: 25 February 2003
RID="a"
ID="a"e-mail: urban@fuw.edu.pl
Communicated by D. Schwalm 相似文献
2.
M. Mirea O. Bajeat F. Clapier F. Ibrahim A.C. Mueller N. Pauwels J. Proust 《The European Physical Journal A - Hadrons and Nuclei》2001,11(1):59-78
The deuteron break-up process in a suitable converter gives rise to intense neutron beams. A source of neutron-rich nuclei
based on the neutron-induced fission can be realised using these beams. A theoretical optimization of such a facility as a
function of the incident deuteron energy is reported. The model used to determine the fission products takes into account
the excitation energy of the target nucleus and the evaporation of prompt neutrons. Results are presented in connection with
a converter-target specific geometry.
Received: 1 December 2000 / Accepted: 12 May 2001 相似文献
3.
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
4.
A.N. Andreyev D. Ackermann P. Cagarda J. Gerl F.P. Heßberger S. Hofmann M. Huyse A. Keenan H. Kettunen A. Kleinböhl A. Lavrentiev M. Leino B. Lommel M. Matos G. Münzenberg C.J. Moore C.D. O'Leary R.D. Page S. Reshitko S. Saro C. Schlegel H. Schaffner M.J. Taylor P. Van Duppen L. Weissman R. Wyss 《The European Physical Journal A - Hadrons and Nuclei》2001,10(2):129-133
The 137I nucleus, populated in the spontaneous fission of 248Cm has been studied by means of prompt γ-ray spectroscopy using the EUROGAM2 array. Medium-spin yrast excitations in 137I were observed for the first time. The experimental level scheme is compared to the shell model calculation with modified
Kuo-Herling interaction. The theoretical predictions differ significantly from the experimental results, indicating that the
excitation pattern in 137I deviates significantly from the shell model scheme.
Received: 6 June 2001 / Accepted: 4 October 2001 相似文献
5.
T. Rzaca-Urban W. Urban A. Kaczor J.L. Durell M.J. Leddy M.A. Jones W.R. Phillips A.G. Smith B.J. Varley I. Ahmad L.R. Morss M. Bentaleb E. Lubkiewicz N. Schulz 《The European Physical Journal A - Hadrons and Nuclei》2000,9(2):165-169
Neutron-rich, 88-94Kr nuclei, populated in spontaneous fission of 248Cm, have been studied with EUROGAM 2, by measuring prompt γ-rays. Many new excited states in even-even Kr isotopes have been
identified. For the first time spins and parities were determined experimentally in these nuclei. Our results indicate that
the quadrupole deformation of Kr isotopes will appear only above N = 58, as observed in Sr and Zr nuclei. The newly found 3- level at 1506.4 keV in 90Kr suggests the exsistence of a new region of increased octupole correlations, probably associated with the ν(d
5/2
h
11/2) pair of Δl = Δj = 3 orbitals.
Received: 18 September 2000 / Accepted: 18 October 2000 相似文献
6.
A. Al-Khatib H. Hübel P. Bringel C. Engelhardt A. Neußer-Neffgen G. B. Hagemann C. R. Hansen B. Herskind G. Sletten A. Bracco F. Camera G. Benzoni P. Fallon R. M. Clark M. P. Carpenter R. V. F. Janssens T. L. Khoo T. Lauritsen P. Chowdhury H. Amro A. K. Singh R. Bengtsson 《The European Physical Journal A - Hadrons and Nuclei》2008,36(1):21-29
Excited states in 124Xe were populated in the reaction 82Se(48Ca, 6n)124Xe and γ -ray coincidence relationships were measured with the Gammasphere spectrometer. Two new bands are observed and several
of the previously known bands are extended in the high- as well as in the low-spin region. Two irregular high-spin structures
are also added. The irregularities are a fingerprint of a transition from collective to non-collective behaviour. Configuration
assignments to the new structures are proposed on the basis of systematics and by comparing experimental properties with calculations
within the framework of the cranking model. 相似文献
7.
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
8.
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
9.
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
10.
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
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.
R. Broda 《The European Physical Journal A - Hadrons and Nuclei》2002,13(1-2):1-4
The use of deep-inelastic heavy-ion reactions for the spectroscopy of neutron-rich nuclei is discussed. Conclusions from the
N/Z equilibration process studies are outlined and examples of spectroscopic results obtained for the neutron-rich spdf shell nuclei, N = 82 isotones and nuclei from the 208Pb region are reviewed.
Received: 1 May 2001 / Accepted: 4 December 2001 相似文献
13.
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
14.
J. Kurpeta G. Lhersonneau A. Płochocki J.C. Wang P. Dendooven A. Honkanen M. Huhta M. Oinonen H. Penttilä K. Peräjärvi J.R. Persson J. Äystö 《The European Physical Journal A - Hadrons and Nuclei》2002,13(4):449-460
The decay of neutron-rich isotope 113Ru obtained as on-line mass separated product of proton-induced fission has been investigated by γγ coincidence and spectrum
multiscaling measurements. Decay schemes for both low- and high-spin isomers of 113Ru have been constructed. The level scheme of 113Rh is considerably extended. Systematics of the lowest-lying rhodium levels is smooth. The picture of shape coexistence established
for neutron-rich Rh isotopes near-neutron midshell is confirmed with the observation of a K = 1/2 deformed band, with its 3/2+ state at 600 keV being the lowest-lying level and of probable 7/2+
and 5/2+
band members. A large fraction of β feeding is found to populate high-lying levels in 113Rh. The GT strength in 113Rum decay is significantly larger than for the decay of 113Rug and of lighter rhodium isotopes.
Received: 18 January 2001 / Accepted: 14 January 2002 相似文献
15.
D.C. Biswas B.K. Nayak M. Cinausero B. Fornal G. Viesti D. Bazzacco M. DePoli D. Fabris E. Fioretto M. Lunardon D.R. Napoli G. Nebbia G. Prete C.A. Ur G. Vedovato 《The European Physical Journal A - Hadrons and Nuclei》1999,4(4):343-348
The high energy γ-ray emission accompanying the spontaneous fission of 252Cf has been measured in coincidence with individual fission fragments selected by discrete γ-ray transitions. The enhancement
of the γ-ray emission probability in the energy range Eγ= 3–8 MeV has been observed for the fission fragments in the region of nearly symmetric mass splitting, confirming results
reported in previous investigations. The γ-γ coincidence technique employed in the present work clearly demonstrate that the
major contribution to this enhancement is caused by the fission channels where one fragment is near to the N= 82 or Z= 50 shell closures. The high energy γ-ray emission probability does not show any significant dependence on the number of
neutrons emitted in the fission process, supporting the hypothesis that high energy γ-rays are mainly emitted from the fragments
after the neutron evaporation.
Received: 22 December 1998 相似文献
16.
A. Bauchet I. Deloncle M.-G. Porquet A. Astier N. Buforn M. Meyer S. Perriès N. Redon B.J.P. Gall F. Hoellinger N. Schulz G. Duchêne S. Courtin Ts. Venkova P.A. Butler N. Amzal R.D. Herzberg A. Chewter R. Cunningham M. Houry R. Lucas W. Urban A. Nowak E. Piasecki J. Duprat C. Petrache T. Kröll 《The European Physical Journal A - Hadrons and Nuclei》2001,10(2):145-150
High-spin states of 103
43Tc have been identified for the first time, this nucleus being produced as fission fragment following the fusion reaction
37Cl + 176Yb at 170 MeV bombarding energy. The high-spin level scheme has been built from the prompt gamma rays detected using the Euroball
III array. It exhibits similarities with those of the neighbouring isotopes and isotones. All the band head configurations
observed in the 97-105Tc isotopes are identified from the behaviour of the rotational bands built on them. The single-proton states located around
the Fermi level are discussed as a function of deformation of these nuclei.
Received: 19 January 2001 / Accepted: 23 February 2001 相似文献
17.
R. Kumar D. Mehta N. Singh H. Kaur A. Görgen S. Chmel R.P. Singh S. Murlithar 《The European Physical Journal A - Hadrons and Nuclei》2001,12(1):5-8
The band structures built on the 5- isomeric state ( T
1/2 = 3.46 m) in the doubly odd 130Cs nucleus have been established up to I = 24? via the 124Sn(11B, 5n)130Cs reaction. The previously observed bands based on the πh
11/2⊗νh
11/2, πg
7/2⊗νh
11/2 and πd
5/2⊗νh
11/2 configurations and a positive-parity side band with multiple connections to the α = 0 signature partner of the yrast πh
11/2⊗νh
11/2 band have been extended to higher spins. A new band based on the πh
11/2⊗νg
7/2 configuration is observed. The yrast πh
11/2⊗νh
11/2 band exhibits anomalous signature splitting whose magnitude decreases up to spin 15 and then increases without restoring
the normal signature splitting.
Received: 20 February 2001 / Accepted: 9 May 2001 相似文献
18.
Xie Yuanxiang Xu Shuwei Li Zhankui Yu Yong Pan Qiangyan Wang Chunfang Zhang Tianmei 《The European Physical Journal A - Hadrons and Nuclei》1999,5(3):239-241
Excited levels in 133Sn and 134Sb, populated in spontaneous fission of 248Cm, were studied by means of prompt-γ spectroscopy, using the EUROGAM 2 multidetector array. The neutron i
13/2 single-particle energy has been determined for the first time in the 132Sn region. The energy of the h
9/2 neutron level, proposed previously, has been confirmed.
Received: 13 January 1999 / Revised version: 22 March 1999 相似文献
19.
A. Jungclaus D. Kast K.P. Lieb C. Lingk C. Teich O. Iordanov T. Härtlein D. Schwalm I.P. Johnstone R. Schwengner 《The European Physical Journal A - Hadrons and Nuclei》1999,6(1):29-36
The magnetic moments of the 12+ and 11− yrast states in 94Ru and of the 25/2−, 29/2+, and 35/2+ levels in 95Rh have been measured via the IMPAD technique. The nuclei were produced in the reaction 58Ni +40Ca and recoil-implanted into polarized Ni and Fe hosts. The g-factors were deduced from the measured time-integral Larmor
precessions. The comparison between the experimental results and large-scale shell model calculations suggests that the 12+ and 11− states in 94Ru and the 25/2− level in 95Rh are pure proton states whereas the 29/2+ and 35/2+ states in 95Rh contain a neutron excitation across the N=50 shell gap. This interpretation supports the conclusion drawn from recent lifetime
measurements.
Received: 2 June 1999 相似文献
20.
N. Yoshinaga K. Higashiyama 《The European Physical Journal A - Hadrons and Nuclei》2006,30(2):343-346
Nuclear structure of doublet bands in doubly odd nuclei with mass A ∼ 130 is investigated within the framework of a simple model where the even-even core couples with a neutron and a proton
in intruder orbitals through a quadrupole-quadrupole interaction. The model reproduces quite well the energy levels of doublet
bands and electromagnetic transitions. The staggering of the ratios B(M1;I → I - 1)/B(E2;I → I - 2) of the yrast bands turns out to be described by the chopsticks-like motion of two angular momenta of the unpaired neutron
and the unpaired proton when they are weakly coupled with the core.-1
An erratum to this article is available at . 相似文献