共查询到20条相似文献,搜索用时 17 毫秒
1.
K. Van de Vel A.N. Andreyev R.D. Page H. Kettunen P.T. Greenlees P. Jones R. Julin S. Juutinen H. Kankaanpää A. Keenan P. Kuusiniemi M. Leino M. Muikku P. Nieminen P. Rahkila J. Uusitalo K. Eskola A. Hürstel M. Huyse Y. Le Coz M.B. Smith P. Van Duppen R. Wyss 《The European Physical Journal A - Hadrons and Nuclei》2003,17(2):167-171
Gamma rays from excited states of 190Po have been observed using the Jurosphere Ge-detector array coupled to the RITU gas-filled separator. They were associated
with a collective band which from spin 4 onwards resembles the prolate rotational bands known in the isotones 188Pb and 186Hg. This indicates that in 190Po the prolate configuration becomes yrast above I = 2. The experimental results are interpreted in a two-band mixing calculation and are in agreement with α-decay data and
potential energy surface calculations.
Received: 10 January 2003 / Accepted: 19 February 2003 / Published online: 7 May 2003 相似文献
2.
A. Tumino M. Lattuada S. Romano C. Spitaleri D. Vinciguerra Z. Basrak O.Yu. Goryunov V.V. Ostashko S. Szilner P. Figuera D. Lo Presti C. Petta N. Randazzo S. Reito G.V. Russo S. Tudisco 《The European Physical Journal A - Hadrons and Nuclei》2001,12(3):327-334
High-spin states of 24Mg produced in the 16O + 12C interaction and decaying into the 16Og.s. + 8Beg.s. channel have been observed in the excitation region between 35 and 52 MeV. Spins have been assigned on the basis of the analysis
of the measured angular correlations. Some of these states with positive parity correspond to the known resonances of the
12C( 12C, 8Beg.s.) 16O reaction belonging to the 16O-2α rotational band of 24Mg. Moreover other resonances show up at higher excitation energy with an energy-spin relationship again suggesting a 16O-2α cluster structure for the associated configuration.
Received: 6 July 2001 / Accepted: 16 October 2001 相似文献
3.
C.-B. Moon T. Komatsubara Y. Sasaki T. Jumatsu K. Yamada K. Satou K. Furuno 《The European Physical Journal A - Hadrons and Nuclei》2002,14(1):13-16
Excited states of the 119Xe nucleus have been studied by using in-beam γ-ray spectroscopy with the 107Ag ( 16O, p3n) 119Xe fusion-evaporation reaction at a beam energy of 85 MeV. The level scheme of 119Xe has been derived from γ-γ coincidence and γ-γ angular correlation analyses. We have, for the first time, established the
second negative-parity favored and unfavored states built on the 11/2- state, namely the yrare rotational bands in 119Xe. In contrast to the behavior of the yrast bands where the favored states are lying lower in energy, the yrare favored states
were observed to lie above the unfavored band. Such a signature inversion in 119Xe is changed to be normal at I = 12?.
Received: 8 January 2002 / Accepted: 18 April 2002 相似文献
4.
S. Sodaye K. Sudarshan B.S. Tomar A. Goswami S. Mukherjee K. Mahata 《The European Physical Journal A - Hadrons and Nuclei》2002,14(3):371-376
Kinetic-energy spectra and angular distribution of projectile-like fragments have been measured in the reaction of 84 MeV
12C on 169Tm, using the surface barrier silicon-based ΔE-E telescopes. The fragments close to the projectile show typical spectra of quasi-elastic transfer reactions, which were found
to be in agreement with the calculations based on the direct surface transfer reaction model. A significant cross-section
of fast alpha-particles was found at forward angles, reminiscent of incomplete fusion reactions, which could be explained
in terms of the direct surface transfer reaction model after taking into account the level density of continuum states in
the heavy reaction product. The results have been explained in terms of the continuous evolution of the reaction mechanism
as a function of the mass transfer.
Received: 13 March 2002 / Accepted: 3 May 2002 相似文献
5.
C. Andreoiu D. Rudolph I. Ragnarsson C. Fahlander R.A.E. Austin M.P. Carpenter R.M. Clark J. Ekman R.V.F. Janssens T.L. Khoo F.G. Kondev T. Lauritsen T. Rodinger D.G. Sarantites D. Seweryniak T. Steinhardt C.E. Svensson O. Thelen J.C. Waddington 《The European Physical Journal A - Hadrons and Nuclei》2002,14(3):317-348
High-spin states in 59Cu were populated using the fusion-evaporation reaction 28Si + 40Ca at a beam energy of 122 MeV. The Gammasphere Ge-detector array in conjunction with the 4π charged-particle detector array
Microball allowed for the detection of γ-rays in coincidence with evaporated light particles. The resulting extensive high-spin
decay scheme of 59Cu is presented, which comprises more than 320 γ-ray transitions connecting about 150 excited states. Their spins and parities
have been assigned via directional correlations of γ-rays emitted from oriented states. Average quadrupole moments of rotational
bands have been determined from the analysis of residual Doppler shifts. Shell model calculations in the fp shell are invoked to study some of the low-spin states, while the experimental characteristics of the rotational bands are
analyzed in the configuration-dependent cranked Nilsson-Strutinsky (CNS) approach.
Received: 15 February 2002 / Accepted: 23 April 2002 相似文献
6.
7.
8.
R.M. Lieder T. Rzaca-Urban H. Brands W. Gast H.M. Jäger L. Mihailescu Z. Marcinkowska W. Urban T. Morek Ch. Droste P. Szymański S. Chmel D. Bazzacco G. Falconi R. Menegazzo S. Lunardi C. Rossi Alvarez G. de Angelis E. Farnea A. Gadea D.R. Napoli Z. Podolyak Ts. Venkova R. Wyss 《The European Physical Journal A - Hadrons and Nuclei》2002,13(3):297-305
High-spin states in 142Gd have been populated by means of the 99Ru(48Ti, 2p3n) reaction at 240 MeV and investigated with the γ-spectrometer EUROBALL III and the charged-particle detector array
ISIS. The features of four dipole bands have been determined and compared with tilted-axis cranking model calculations indicating
that they are magnetic rotational bands. A transition from regular to irregular bands has been found approaching N = 82 demonstrating that this is a general phenomenon in nuclei near a double-shell closure.
Received: 9 December 2001 / Accepted: 9 January 2002 相似文献
9.
L. Vannucci P. Boccaccio A. Bologna R.A. Ricci G. Vannini R. Donà I. Massa J.P. Coffin P. Fintz G. Guillaume F. Jundt F. Rami P. Wagner 《The European Physical Journal A - Hadrons and Nuclei》2000,7(1):65-77
Final states indicating the presence in the reaction of three-body fragmentation processes has been observed in 32S+59Co and 32S+63Cu dissipative collisions at 5.6 A · MeV. Besides the already observed sequential binary process, data analysis reveals the
presence of prompt ternary break-up of the composite system. Indications on the system configuration at the scission have
been deduced by analyzing the event shape in the momentum phase space. The decay appears to occur in a collinear configuration,
one of the produced fragments originating from the neck which connects the other two. In spite of the large energy dissipation,
structure effects in the charge partition seem to affect part of events.
Received: 3 July 1998 / Revised version: 15 October 1999 相似文献
10.
K.A. Schmidt M. Bergström G.B. Hagemann B. Herskind G. Sletten P.G. Varmette J. Domscheit H. Hübel S.W. Ødegård S. Frattini A. Bracco B. Million M.P. Carpenter R.V.F. Janssens T.L. Khoo T. Lauritsen C.J. Lister S. Siem I. Wiedenhöver D.J. Hartley L.L. Riedinger A. Maj W.C. Ma R. Terry 《The European Physical Journal A - Hadrons and Nuclei》2001,12(1):15-28
High-spin properties of the nucleus 169Hf have been studied through the fusion evaporation reaction 96Zr(76Ge,3n)169Hf at a beam energy of 310 MeV. The known rotational bands have been extended considerably and 6 new bands have been established,
four of which form coupled bands with pronounced M1 connections. Quasiparticle assignments are suggested for the new band structures, and it appears that coupling to vibrational
degrees of freedom plays a role. Both coupled bands involve the excitation of quasiprotons. In the region of highest spin,
a large alignment gain is interpreted in terms of a mixed crossing where an h
9/2 and an h
11/2 quasiproton provide the two signatures of the aligning configuration.
Received: 23 March 2001 / Accepted: 20 September 2001 相似文献
11.
Z. Sosin 《The European Physical Journal A - Hadrons and Nuclei》2001,11(3):311-317
We propose a two-stage, stochastic model of heavy-ion reactions. Nucleons becoming participants by mean-field effects or by
nucleon-nucleon interactions are transferred to definite final states, creating a PLF, a TLF, clusters, or escaping to continuum.
Nucleon transfer probabilities are governed by state densities. In this way different hot particle sources are created which
afterwards decay by particle emission.
Received: 12 March 2001 / Accepted: 20 June 2001 相似文献
12.
G. Casini M. Bini S. Calamai R. Laforest P.R. Maurenzig A. Olmi G. Pasquali S. Piantelli G. Poggi F. Saint-Laurent J.C. Steckmeyer A.A. Stefanini N. Taccetti 《The European Physical Journal A - Hadrons and Nuclei》2000,9(4):491-513
Primary and secondary masses of heavy reaction products have been deduced from kinematics and E-ToF measurements, respectively,
for the direct and reverse collisions of 93Nb and 116Sn at 25 AMeV. Light charged particles have also been measured in coincidence with the heavy fragments. Direct experimental
evidence of the correlation of energy-sharing with net mass transfer has been found using information from both the heavy
fragments and the light charged particles. The ratio of hydrogen and helium multiplicities points to a further correlation
of angular momentum sharing with net mass transfer.
Received: 18 September 2000 / Accepted: 2 December 2000 相似文献
13.
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
14.
R. Płaneta W. Gawlikowicz A. Wieloch J. Brzychczyk T. Ciszek A.J. Cole P. Désesquelles K. Grotowski P. Hachaj S. Micek P. Pawłowski Z. Sosin D. Benchekroun E. Bisquer A. Chabane M. Charvet B. Cheynis A. Demeyer E. Gerlic A. Giorni D. Guinet D. Heuer P. Lautesse L. Lebreton A. Lléres M. Stern L. Vagneron J.B. Viano 《The European Physical Journal A - Hadrons and Nuclei》2001,11(3):297-304
The creation of hot Ca-like fragments was investigated in the 40Ca + 40Ca reaction at 35 AMeV. Using the AMPHORA 4π detector system, the primary projectile-like fragment was reconstructed and its
properties were determined. Both primary and secondary distributions are compared with the predictions of a Monte Carlo code
describing a heavy-ion collision as a two-step process. Some of the nucleons which are identified as participants in the first
step are transferred in the second step to these final states, which correspond on the average to the maximum value of entropy
(thermodynamic probability). The model allows for competition between mean-field effects and nucleon-nucleon interactions
in the overlap zone of the interacting nuclei. The analysis presented here suggests a thermalized source picture of the decay
of the projectile-like fragment. The validity of the reconstruction procedure for projectile-like fragments is discussed.
Received: 12 March 2001 / Accepted: 20 June 2001 相似文献
15.
K.-M. Källman M. Brenner V.Z. Goldberg T. Lönnroth P. Manngård A.E. Pakhomov V.V. Pankratov 《The European Physical Journal A - Hadrons and Nuclei》2003,16(2):159-169
The excitation function and angular distributions of elastic α-particle scattering on 28Si have been measured in the laboratory energy range 6-28 MeV using a backscattering technique on a thick target, yielding
a continuous energy distribution. More than 200 narrow states are observed, with widths in the range ∼ 30-100 keV at excitation
energies E
* = 13-32 MeV. Angular distributions at backward angles were measured, and angular momentum values of more than 83 states have
been deduced. The analysis gives spin-parities J
π, α-partial widths Γα and reduced widths of the narrow high-lying resonant states in 32S. The experimentally observed states display both the negative- and the positive-parity rotational-like sequences with seemingly
no parity splitting, a finding which is at variance with most potential-model predictions. The deduced effective moment of
inertia indicates a more extended structure than the ground-state configuration. The observed strength of each ℓ-value is
analyzed in terms of an underlying split doorway state of Lorentzian form, which yields an interpretation as fragmented rotational
α + 28Si states.
Received: 26 June 2000 / Accepted: 16 September 2002 / Published online: 4 February 2003
RID="a"
ID="a"e-mail: kkallman@abo.fi
RID="b"
ID="b"Present address: Swedish Polytechnic, FIN-65200 Vasa, Finland.
Communicated by D. Guerreau 相似文献
16.
Y. Toh T. Czosnyka M. Oshima T. Hayakawa H. Kusakari M. Sugawara Y. Hatsukawa J. Katakura N. Shinohara M. Matsuda 《The European Physical Journal A - Hadrons and Nuclei》2000,9(3):353-356
74Ge beam was Coulomb-excited on a natPb target. Ten E2 matrix elements including diagonal matrix elements for 5 low-lying states have been determined using the least-squares search
code GOSIA. The expectation values of the rotational invariants 〈Q
2〉 and 〈cos3δ〉 show the small and triaxial deformation of the two lowest members of the ground-state band , while the 02
+ and 22
+ states are found to be almost spherical.
Received: 31 August 2000 / Accepted: 4 December 2000 相似文献
17.
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
18.
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
19.
20.
R.S. Chakrawarthy B.S. Nara Singh R.G. Pillay 《The European Physical Journal A - Hadrons and Nuclei》1998,3(1):5-8
High spin states in 108In have been established upto ∼ 8 MeV in excitation energy and to a tentative spin of (23−). The data were obtained by in-beam γ-ray spectroscopy using the reaction 93Nb(19F, p3n)108In at a beam energy of 86 MeV. Four sequences of dipole bands and a normal rotational band of E2 γ-transitions have been placed
in the level scheme.
Received: 16 June 1998 相似文献