共查询到20条相似文献,搜索用时 15 毫秒
1.
A. Dhal R. K. Sinha P. Agarwal S. Kumar Monika B. B. Singh R. Kumar P. Bringel A. Neusser R. Kumar K. S. Golda R. P. Singh S. Muralithar N. Madhavan J. J. Das A. Shukla P. K. Raina K. S. Thind A. K. Sinha I. M. Govil P. K. Joshi R. K. Bhowmik A. K. Jain S. C. Pancholi L. Chaturvedi 《The European Physical Journal A - Hadrons and Nuclei》2006,27(1):33-36
High-spin states in 78Kr have been studied via the 63Cu (19F, 2p2n)78Kr reaction at a beam energy of 60 MeV using the Indian National Gamma Array (INGA). In this nucleus, lifetimes have been
measured upto the Iπ=22+ level in the yrast positive-parity band and upto the Iπ=15- level in the negative-parity band using the Doppler Shift Attenuation Method (DSAM). The deduced transition quadrupole moments
Qt's are found to decrease with rotational frequency for both the bands. 相似文献
2.
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
3.
T. Steinhardt J. Eberth I. Ragnarsson 《The European Physical Journal A - Hadrons and Nuclei》2007,33(4):303-306
Based on the γ -spectroscopic analysis of G.N. Sylvan et al., configuration-dependent cranked Nilsson-Strutinsky calculations have been performed. They describe the nucleus 77Kr globally in good agreement with the experimental findings and the expectations derived from single-particle orbitals in
a deformed potential. Within these calculations, the unambiguous assignment of a configuration with three protons and five
neutrons in the g
9/2 shell to the high-spin Yrast states of negative parity indicates that the nucleus 77Kr has stable triaxial deformation and rotates about the intermediate axis. This not only disproves the recent interpretation
of an occupation of the d
5/2 orbital being responsible for the strong deformation in this band, but also represents one of the first examples in this
mass region for such a rotation. 相似文献
4.
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
5.
M. Fantuzi C. M. Petrache D. Mengoni M. Axiotis D. Bazzacco G. Benzoni P. G. Bizzeti A. M. Bizzeti-Sona N. Blasi A. Bracco G. de Angelis E. Farnea A. Gadea Th. Kröll S. Leoni H. L. Liu S. Lunardi N. Marginean R. Menegazzo D. R. Napoli M. Nespolo P. Pavan C. Rossi Alvarez P. Spolaore C. A. Ur R. Venturelli F. R. Xu 《The European Physical Journal A - Hadrons and Nuclei》2008,38(1):43-51
Excited states in the very neutron-deficient122La nucleus have been established for the first time using the92Mo(40Ca, 2α1p1n) reaction at beam energies of 190 and 200MeV. The observed transitions were grouped in three bands. Configurations have been
assigned to the observed bands based on the properties extracted from the experimental data and on cranked shell model calculations. 相似文献
6.
M. -G. Porquet Ts. Venkova A. Astier I. Deloncle A. Prévost 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》2006,28(2):153-159
The 87Kr nucleus has been produced as fission fragment in the fusion reaction 18O + 208Pb at 85MeV bombarding energy and studied with the Euroball IV array. High-spin states of this neutron-rich isotope have been
identified for the first time. Its level scheme has been obtained up to 6.3MeV excitation energy and spin I ∼ 23/2ℏ. Its structure is interpreted by analogy with those of the heavier isotones. The proposed configurations involve
both proton and neutron excitations from several sub-shells located close to the Fermi levels, particularly νd5/2, πp3/2f5/2 and πg9/2. Moreover, a revised spin value of 5/2- for the 87Br ground state is proposed. 相似文献
7.
I. Piqueras M.J.G. Borge Ph. Dessagne J. Giovinazzo A. Huck A. Jokinen A. Knipper C. Longour G. Marguier M. Ramdhane V. Rauch O. Tengblad G. Walter Ch. Miehé 《The European Physical Journal A - Hadrons and Nuclei》2003,16(3):313-329
The beta-decay of the N = Z, even-even nucleus 72Kr has been studied at the ISOLDE PSB facility at CERN. Measurements of βγ and βγγ coincidences have enriched the decay scheme
of the daughter nucleus 72Br with 27 new low spin levels. A more precise half-life of T
1/2 = 17.1(2) s has been determined. Strong feeding to the 72Br ground state is established yielding an unambiguous J
π = 1+ assignment for this state. Candidates for the 72Br g.s. wave function are discussed in the framework of a self-consistent deformed mean-field calculation with SG2 Skyrme
force and pairing correlations. A search for beta-delayed particle emission was made and an upper limit of 10-6 for this decay branch obtained. The cumulated experimental level density of 1+ states has been fitted with the constant temperature formula. The comparison indicates that most likely all 1+ levels up to 1.2 MeV have been observed in this investigation. The corresponding nearest-neighbour level spacing does not
follow a Poisson distribution. The Gamow-Teller strength distribution is compared, in terms of nuclear deformation, with different
calculations made in the framework of the quasiparticle random phase approximation.
Received: 7 February 2002 / Accepted: 31 October 2002 / Published online: 6 March 2003
RID="a"
ID="a"e-mail: borge@pinar2.csic.es
RID="b"
ID="b"Present address: Centre d' Etudes Nucléaires de Bordeaux-Gradignan, Le Haut Vigneau, F-33175 Gradignan Cedex, France.
RID="c"
ID="c"Present address: University Mentouri, 25000 Constantine, Algeria.
Communicated by J. ?yst? 相似文献
8.
A. Kankainen G. K. Vorobjev S. A. Eliseev W. Huang J. Huikari A. Jokinen A. Nieminen Yu. N. Novikov H. Penttilä A. V. Popov S. Rinta-Antila H. Schatz D. M. Seliverstov Yu. P. Suslov J. Äystö 《The European Physical Journal A - Hadrons and Nuclei》2005,25(3):355-363
Decay properties of neutron-deficient exotic nuclei close to A=80 have been investigated at the IGISOL facility. The studied nuclei, 81Y, 81Sr, 81mKr, 85Nb, 85Zr, 86Mo and 86Nb, were produced by a 32S beam from the Jyv?skyl? isochronous cyclotron on 54Fe and natNi targets. The internal conversion coefficient for a 190.5 keV isomeric transition in 81mKr has been measured and the internal transition rate has been determined. The internal transition rate has been used to estimate
a neutrino capture rate on 81Br, which yields a log ft of 5.13±0.09 for the reaction 81Br( ν, e
-)81mKr. A new isomer with a half-life of 3.3±0.9 s has been observed in 85Nb. The existence of an earlier reported isomer with a half-life of 56 s in 86Nb has not been confirmed. 相似文献
9.
Zs. Podolyák P.G. Bizzeti A.M. Bizzeti-Sona S. Lunardi D. Bazzacco A. Dewald A. Algora G. de Angelis E. Farnea A. Gadea D.R. Kasemann T. Klug Th. Kröll S. Lenzi D.R. Napoli C.M. Petrache R. Peusquens C. Rossi Alvarez T. Martinez C.A. Ur 《The European Physical Journal A - Hadrons and Nuclei》2003,17(1):29-36
Lifetimes of excited states in 148Gd were measured using the recoil distance method with a plunger device coupled to the EUROBALL Ge detector array. The differential
decay curve method in coincidence mode allowed the unambiguous determination of lifetimes of more than 20 excited states.
The obtained transition strengths are in good agreement with the shell model calculations. The effect of the Z = 64 subshell closure on the B(E2 : 2+ → 0+) reduced strengths above the N = 82 magic number is discussed.-1
Received: 14 November 2002 / Accepted: 4 February 2003 / Published online: 29 April 2003 相似文献
10.
E. O. Lieder A. A. Pasternak R. M. Lieder A. D. Efimov V. M. Mikhajlov B. G. Carlsson I. Ragnarsson W. Gast Ts. Venkova T. Morek S. Chmel G. de Angelis D. R. Napoli A. Gadea D. Bazzacco R. Menegazzo S. Lunardi W. Urban Ch. Droste T. Rzaca-Urban G. Duchêne A. Dewald 《The European Physical Journal A - Hadrons and Nuclei》2008,35(2):135-158
For a level scheme investigation of 142Gd an experiment with the γ -spectrometer EUROBALLIII has been carried out and lifetimes have been measured with EUROBALL
IV using the Doppler-shift attenuation method. The high-spin states have been populated in these experiments by means of the
99Ru(48Ti, 2p3n) reaction at a beam energy of 240MeV and the 114Sn(32S, 2p2n) reaction at 160MeV, respectively. Reduced E2 transition probabilities B(E2) were determined for 15 members of four quadrupole bands. For the interpretation of the positive-parity even-spin quadrupole
bands, calculations in the cranked Nilsson-Strutinsky as well as interacting boson models have been performed. From the former
calculations it was concluded that the high-spin states of the (+ , 0)1 band in 142Gd represent a triaxial nucleus rotating around the longest principal axis. 相似文献
11.
M. Lach J. Styczeń W. Meczyński P. Bednarczyk A. Bracco J. Grebosz A. Maj J.C. Merdinger N. Schulz M.B. Smith K.M. Spohr J.P. Vivien M. Ziebliński 《The European Physical Journal A - Hadrons and Nuclei》2003,16(3):309-311
High-spin states of the 42Ca nucleus, populated in the 68 MeV 18O + 30Si reaction, have been studied in a γ-γ-recoil coincidence experiment. The level scheme of 42Ca has been extended up to 13.7 MeV. An elaborate decay pattern with various paths, together with high-quality DCO and polarization
information assigns spins and parities for almost all observed levels. The sequence of non-yrast positive-parity states is
discussed and compared with highly deformed bands in 36Ar and 40Ca.
Received: 26 November 2002 / Accepted: 11 December 2002 / Published online: 18 February 2003
RID="a"
ID="a"e-mail: Malgorzata.Lach@ifj.edu.pl
RID="b"
ID="b"Present address: TRIUMF, Vancouver, Canada.
RID="†"
ID="†"Deceased.
Communicated by D. Schwalm 相似文献
12.
R. K. Sinha A. Dhal P. Agarwal S. Kumar Monika B. B. Singh R. Kumar P. Bringel A. Neusser R. Kumar K. S. Golda R. P. Singh S. Muralithar N. Madhavan J. J. Das K. S. Thind A. K. Sinha I. M. Govil R. K. Bhowmik J. B. Gupta P. K. Joshi A. K. Jain S. C. Pancholi L. Chaturvedi 《The European Physical Journal A - Hadrons and Nuclei》2006,28(3):277-281
High-spin states in 79Rb were populated in the reaction
at E(beam) = 60 MeV. The lifetimes of the excited states of the
positive-parity yrast band and of the
negative-parity band in 79Rb were measured by the Doppler Shift Attenuation Method. The deduced transition quadrupole moments Qt are found to have a decreasing trend with rotational frequency for both the bands, consistent with those found experimentally
in neighbouring nuclei.
An erratum to this article is available at . 相似文献
13.
14.
Ts. Venkova W. Gast R. M. Lieder D. Bazzacco G. de Angelis E. O. Lieder A. A. Pasternak R. Menegazzo S. Lunardi C. Rossi Alvarez C. Ur T. Martinez M. Axiotis D. Napoli W. Urban T. Rzaca-Urban S. Frauendorf 《The European Physical Journal A - Hadrons and Nuclei》2005,26(1):19-24
High-spin states in the neutron-rich nuclei 172,173Yb have been populated in a 170Er(7Li,(p,d,t)xn) incomplete-fusion reaction and the emitted γ-radiation was detected with the GASP array. The signature partners of the
7/2+[633] rotational band of the odd-N 173Yb isotope have been newly established and were observed up to spin values of (45/2+) and (43/2+), respectively. The ground-state band of the even-even nucleus 172Yb has been observed up to a spin value of (22+). No band crossings were found in these bands. To explain this observation, it is proposed that the static pair field is
absent, considering that the neutron odd-even mass differences reach for these nuclei very small values and that the band
crossing is absent in cranked shell modell calculations without pairing. The results indicate, however, that strong dynamic
correlations are still present. 相似文献
15.
E. K. Johansson D. Rudolph J. Ekman C. Fahlander C. Andreoiu M. A. Bentley M. P. Carpenter R. J. Charity R. M. Clark P. Fallon R. V. F. Janssens F. G. Kondev T. L. Khoo T. Lauritsen A. O. Macchiavelli W. Reviol D. G. Sarantites D. Seweryniak C. E. Svensson S. J. Williams 《The European Physical Journal A - Hadrons and Nuclei》2006,27(2):157-165
The doubly magic N = Z nucleus 56Ni has been investigated with two fusion-evaporation reactions; 40Ca(28Si, 3α)56Ni at a beam energy of 122MeV and 28Si(32S, 2p2n)56Ni at 130MeV. To detect γ-rays in coincidence with evaporated particles the Ge-detector array Gammasphere was used in conjunction
with the charged-particle detector system, Microball and a 1π neutron detector array. Results include a significantly extended
level scheme of 56Ni, which is compared to large-scale shell model calculations in the fp shell. The experimental and theoretical results agree to a large extent, with one notable exception; the theoretical model
fails to predict the proper sequence of the yrast and yrare 8+ states. 相似文献
16.
The nuclear spectroscopic quadrupole moments for the πh9/25/2-, 1/2-[541] and the πh11/29/2-, 9/2-[514] isomeric states in 169Ta have been measured employing the time differential perturbed angular-distribution technique following the nuclear reaction
159Tb(16O, 6nγ)169Ta at beam energy 104 MeV. The ratio of the intrinsic quadrupole moments
has been derived as 1.87(13) from the measured quadrupole precession frequencies of the corresponding states. The model-independent
analysis of the equilibrium deformation indicates strong prolate- and oblate-driving nature of the 1/2-[541] and 9/2-[514] orbitals in 169,171Ta isotopes, respectively. 相似文献
17.
The lifetimes of the states of −ve parity 2-qp bands of N=40 nuclei 74Se and 76Kr were measured. The transition strengths and quadrupole moments, obtained from the lifetimes, show a large collectivity
of such bands in both the nuclei. The alignment frequencies were calculated from Woods-Saxon cranking model. Previously suggested
quasi proton nature of band 5 and 6 of 71Se were argued to be based on quasi neutron excitations. The total Routhian surface calculations suggest triaxial shapes with
large +ve and −ve values of triaxiality parameter γ after proton and neutron alignments in these bands respectively. 相似文献
18.
C. Andreoiu M. Axiotis G. de Angelis J. Ekman C. Fahlander E. Farnea A. Gadea T. Kröll S.M. Lenzi N. Mărginean T. Martinez M.N. Mineva C. Rossi Alvarez D. Rudolph C.A. Ur 《The European Physical Journal A - Hadrons and Nuclei》2002,15(4):459-462
Excited states in 59Zn were observed for the first time following the fusion-evaporation reaction 24Mg + 40Ca at a beam energy of 60 MeV. The GASP array in conjunction with the ISIS Silicon ball and the NeutronRing allowed for the
detection of γ-rays in coincidence with evaporated light particles. The mirror symmetry of 59Zn and 59Cu is discussed.
Received: 28 May 2002 / Accepted: 10 July 2002 / Published online: 3 December 2002
RID="a"
ID="a"Present address: Oliver Lodge Laboratory, University of Liverpool, P.O. Box 147, Liverpool, L69 7ZE, United Kingdom; e-mail: ca@ns.ph.liv.ac.uk.
RID="b"
ID="b"Present address: Physik-Departament, Technische Universit?t München, D-85748 Garching, Germany.
Communicated by W. Henning 相似文献
19.
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
20.
Deformed configuration mixing shell model based on Hartree-Fock states with extension to include isospin projection (DSMT) for two- and four-particle configurations (generated by particle-hole excitations) is applied to study the structure of the low-lying T = 0, 1 and 2 bands (or levels) in the even-even N = Z nuclei 52Fe and 72Kr. The pf-shell KB3 interaction for 52Fe and a modified Kuos interaction for 72Kr are employed in the calculations. In this first application of DSMT with four-particle T projection, low-spin (J 10) members of the T = 0, 1 and 2 bands in 52Fe are compared with experiment including the known E2 transition strengths. The agreement between DSMT and experiment is reasonably good. Similarly, the low-spin members of the observed (prolate) yrast band in 72Kr are also well described by DSMT. 相似文献