共查询到20条相似文献,搜索用时 15 毫秒
1.
Y. Fujita H. Fujita T. Adachi G.P.A. Berg E. Caurier H. Fujimura K. Hara K. Hatanaka Z. Janas J. Kamiya T. Kawabata K. Langanke G. Martınez-Pinedo T. Noro E. Roeckl Y. Shimbara T. Shinada S.Y. van der Werf M. Yoshifuku M. Yosoi R.G.T. Zegers 《The European Physical Journal A - Hadrons and Nuclei》2002,13(4):411-418
Under the assumption that isospin is a good quantum number, symmetry is expected for the transitions from the ground states
of T = 1, T
z = ±1 nuclei to the common excited states of the T
z = 0 nucleus situated between the two nuclei. The symmetry can be studied by comparing the strengths of Gamow-Teller (GT)
transitions obtained from a (p, n)-type charge-exchange reaction on a target nucleus with T
z = 1 with those from the β-decay of the T
z = - 1 nucleus. The A = 58 system is the heaviest for which such a comparison is possible. As a part of the symmetry study, we measured the GT
transitions from 58Ni (T
z = 1) to 58Cu (T
z = 0) by using the zero-degree (3
He, t) reaction at 150 MeV/nucleon. With the achieved resolution of 50 keV, many hitherto unresolved GT states have been identified.
The GT transition strengths were obtained for states up to 8 MeV excitation, i.e., near to the Q window limitation ( Q
EC = 9.37 MeV) of the β-decay from 58Zn (T
z = - 1) to 58Cu. The strength distribution is compared with that from shell-model calculations.
Received: 24 November 2001 / Accepted: 30 January 2002 相似文献
2.
D. Rudolph D.G. Sarantites C. Andreoiu C. Fahlander D.P. Balamuth R.J. Charity M. Devlin J. Eberth A. Galindo-Uribarri P.A. Hausladen D. Seweryniak L.G. Sobotka Th. Steinhardt 《The European Physical Journal A - Hadrons and Nuclei》2002,14(2):137-146
Prompt proton decay lines in 58Cu have been studied by means of high-resolution in-beam particle-γ coincidence spectroscopy using the GAMMASPHERE Ge-detector
array in conjunction with a dedicated set of ancillary detectors including four ΔE-E silicon-strip telescopes. High-spin states in 58Cu have been populated via the heavy-ion fusion-evaporation reaction 28Si(36Ar, 1α1p1n) at 148 MeV beam energy. The full-width at half maximum for the proton peak could be reduced significantly compared
to earlier experiments. The results indicate that only one prompt proton decay branch exists in the decay-out of the well-deformed
band of 58Cu.
Received: 11 March 2002 / Accepted: 10 April 2002 相似文献
3.
N. Gelli F. Lucarelli M. Cinausero E. Fioretto G. Prete D. Fabris M. Lunardon G. Nebbia G. Viesti D. Bazzacco C.A. Ur D.R. Napoli P. Pavan C. Rossi Alvarez P.F. Bortignon E.M. Fiore L. Fiore V. Paticchio B. Fornal 《The European Physical Journal A - Hadrons and Nuclei》2000,7(3):361-365
The high energy γ-rays from the fusion-evaporation reaction 101 MeV 19F +181Ta have been measured in coincidence with different γ-ray fold windows or discrete γ-rays in final residual nuclei. The line-shape
analysis of the high energy γ-ray spectra confirms the large deformation of the 200Pb nuclei at high angular momenta. Coincidences with discrete γ-transitions evidence a strong correlation between γ-rays in
the Giant Dipole Resonance region (Eγ≥ 8 MeV) and final evaporation residues.
Received: 14 September 1999 / Revised version: 17 December 1999 相似文献
4.
D. Rudolph C. Baktash M.J. Brinkman M. Devlin H.-Q. Jin D.R. LaFosse L.L. Riedinger D.G. Sarantites C.-H. Yu 《The European Physical Journal A - Hadrons and Nuclei》1999,4(2):115-145
High-spin states of nuclei near doubly magic 56Ni were studied with the reaction 28Si(36Ar,xpynzα) at 136 MeV beam energy. The Gammasphere array in conjunction with the 4π charged-particle detector array Microball and
neutron detectors were used to detect γ rays in coincidence with evaporated light particles. The resulting extensive decay
schemes of 54Fe, 54,55Co, 56,57Ni, and 58Cu are compared to shell model calculations in the fp shell.
Received: 19 September 1998 / Revised version: 27 November 1998 相似文献
5.
M. Lach P. Bednarczyk A. Bracco J. Grębosz M. Kadłuczka N. Kintz A. Maj J.C. Merdinger W. Męczyński J.L. Pedroza N. Schulz M.B. Smith K.M. Spohr J. Styczeń J.P. Vivien M. Ziębliński 《The European Physical Journal A - Hadrons and Nuclei》2001,12(4):381-382
High-spin states of the 44Ca nucleus populated in the 68 MeV 18O + 30Si reaction have been studied in a γ-γ-recoil coincidence experiment. The level scheme of 44Ca has been extended up to 12.2 MeV. In particular, the negative-parity band has been identified with the highest I = 13- level at 10.6 MeV. This state is interpreted as the band-terminating state for the ( d
3/2
-1
f
7/2
5) configuration.
Received: 7 November 2001 / Accepted: 3 December 2001 相似文献
6.
D. Rudolph D. Weisshaar F. Cristancho J. Eberth C. Fahlander O. Iordanov S. Skoda Ch. Teich O. Thelen H.G. Thomas 《The European Physical Journal A - Hadrons and Nuclei》1999,6(4):377-380
The neutron g
9/2 single-particle state in 57Ni has been unambiguously identified in a combined measurement of the linear polarization, angular distribution, and angular
correlation of γ rays following the fusion-evaporation reaction 28Si(32S,2pn)57Ni at a beam energy of 90 MeV. The linear polarization was measured with a Euroball cluster detector and a prototype of an encapsulated six-fold segmented hexaconical Ge-detector. The spin of the 3701 keV
level in 57Ni was confirmed to be I= 9/2 and its parity determined to be positive.
Received: 24 September 1999 / Revised version: 22 October 1999 相似文献
7.
J. Giovinazzo B. Blank C. Borcea M. Chartier S. Czajkowski G. de France R. Grzywacz Z. Janas M. Lewitowicz F. de Oliveira Santos M. Pfützner M.S. Pravikoff J.C. Thomas 《The European Physical Journal A - Hadrons and Nuclei》2001,10(1):73-84
Decay studies of very neutron-deficient nuclei ranging from 39Ti to 49Ni have been performed during a projectile fragmentation experiment at the GANIL/LISE3 separator. For all nuclei studied in
this work, 39, 40Ti, 42, 43Cr, 46Mn, 45, 46, 47Fe and 49Ni, half-lives and decay spectra have been measured. In a few cases, γ coincidence measurements helped to successfully identify
the initial and final states of transitions. In these cases, partial decay scheme are proposed. For the most exotic isotopes,
39Ti, 42Cr, 45Fe and 49Ni, which are candidates for two-proton radioactivity from the ground state, no clear evidence of this process is seen in
our spectra and we conclude rather on a delayed particle decay.
Received: 26 July 2000 / Accepted: 20 December 2000 相似文献
8.
M.N. Harakeh 《The European Physical Journal A - Hadrons and Nuclei》2002,13(1-2):169-175
First-generation radioactive ion-beam facilities have already been in operation for some time. Advanced facilities that will
deliver high-intensity radioactive nuclear beams ranging in energy from below the Coulomb barrier to up to several hundred
MeV per nucleon (MeV/u) are either starting operation, or under construction or in the planning stage. In this paper the perspectives
of using radioactive nuclear beams to study giant resonances in nuclei far from the valley of stability are explored. In particular,
emphasis will be made on information on certain nuclear properties that can be gained from such studies.
Received: 1 May 2001 / Accepted: 4 December 2001 相似文献
9.
Th. Andersson D. Rudolph C. Baktash J. Eberth C. Fahlander D. Haslip D.R. LaFosse S.D. Paul D.G. Sarantites C.E. Svensson H.G. Thomas J.C. Waddington W. Weintraub J.N. Wilson B.A. Brown 《The European Physical Journal A - Hadrons and Nuclei》1999,6(1):5-8
High-spin states of the mass A= 39 mirror pair 39K and 39Ca were investigated via the fusion-evaporation reaction 28Si +16O at 125 MeV beam energy. The Gammasphere array in conjunction with the 4π charged-particle detector array Microball and neutron detectors was used to detect γ rays in coincidence with evaporated light particles. The results of the first
high-spin study of the T
z=−1/2 nucleus 39Ca are discussed in terms of mirror symmetry and compared to spherical shell-model calculations in the 1d
3/2–; 1f
7/2 configuration space.
Received: 18 August 1999 相似文献
10.
M.N.A. Abdullah M.S. Mahbub S.K. Das A.S.B. Tariq M.A. Uddin A.K. Basak H.M. Sen Gupta F.B. Malik 《The European Physical Journal A - Hadrons and Nuclei》2002,15(4):477-486
Full finite-range macroscopic calculations in the distorted-wave Born approximation have been performed using the molecular
and Michel α-nucleus potentials to analyze the angular distributions of cross-sections of the 27Al(α, d)29Si reaction, at 26.5 and 27.2 MeV incident energies, leading to seven transitions up to the excitation energy E
X = 4.08 MeV of the final nucleus. The parameters of the two types of the α-nucleus potentials are determined from the elastic-scattering
data. Both the molecular and Michel potentials, without any adjustment to the parameters needed to fit the elastic-scattering
data, are able in most cases to reproduce, simultaneously, the absolute cross-sections particularly at large angles, where
the previous calculations failed to reproduce by orders of magnitude, and the gross pattern of angular distributions of the
reaction. The deuteron-cluster spectroscopic factors for most of the seven transitions, deduced using the two α-27Al potentials, differ from those obtained in earlier works. The spectroscopic factor for the ground-state transition, deduced
in the present work for the 25.8 MeV data, agrees well with the shell model prediction.
Received: 15 July 2002 / Accepted: 8 August 2002 / Published online: 10 December 2002
RID="a"
ID="a"e-mail: akbasak2001@Yahoo.com
Communicated by G. Orlandini 相似文献
11.
A. Jokinen M. Oinonen J. Äystö P. Baumann P. Dendooven F. Didierjean V. Fedoseyev A. Huck Y. Jading A. Knipper M. Koizumi U. Köster J. Lettry P.O. Lipas W. Liu V. Mishin M. Ramdhane H. Ravn E. Roeckl V. Sebastian G. Walter 《The European Physical Journal A - Hadrons and Nuclei》1998,3(3):271-276
Beta decay of 58Zn has been studied for the first time. A new laser ion-source concept has been used to produce mass-separated sources for
beta and gamma spectroscopy. The half-life of 58Zn was determined to be 86(18) ms. Comparisons are made with previous data from charge-exchange reactions. Our Gamow–Teller
strength to the 1+ state at 1051 keV excitation in 58Cu agrees well with the value extracted from a recent (3He, t) study. Extensive shell-model calculations are presented.
Received: 5 June 1998 / Revised version: 24 July 1998 相似文献
12.
M. Papa F. Amorini M. Cabibbo G. Cardella A. Di Pietro P. Figuera A. Musumarra G. Pappalardo F. Rizzo S. Tudisco 《The European Physical Journal A - Hadrons and Nuclei》1999,4(1):69-82
Recent experimental results on particles-γ coincidence measurements on the systems 12C +64Ni and 35Cl +64Ni at about 8 MeV/nucleon are interpreted as due to the effect of a Dipole pre-equilibrium emission produced during the damping
of the proton-neutron relative collective motion in very deformed intermediate systems formed in the first instants of the
collision. The pre-equilibrium effects are evaluated through semiclassic kinetic theories and through modified statistical
approach to include non-stationary effects in Fusion processes, Massive Transfer reactions (in the 12C +64Ni system) and in Binary Dissipative reactions (in the 35Cl +64Ni system). In particular the study performed on the dipole molecular component allows to establish a link between the above
phenomenon and the charge and mass transfer process in quasi-peripheral reactions.
Received: 15 April 1998 / Revised version: 8 June 1998 相似文献
13.
S. Yildirim A. Gokalp O. Yilmaz S. Ayik 《The European Physical Journal A - Hadrons and Nuclei》2001,10(3):289-294
Collisional damping widths of giant monopole and quadrupole excitations for 120Sn and 208Pb at zero and finite temperatures are calculated within Thomas-Fermi approximation by employing the microscopic in-medium
cross-sections of Li and Machleidt and the phenomenological Skyrme and Gogny forces, and are compared with each other. The
results for the collisional widths of giant monopole and quadrupole vibrations at zero temperature as a function of the mass
number show that the collisional damping of giant monopole vibrations accounts for about 30 - 40% of the observed widths at
zero temperature, while for giant quadrupole vibrations it accounts for only 20 - 30% of the observed widths at zero temperature.
Received: 9 January 2001 / Accepted: 29 March 2001 相似文献
14.
Gamow-Teller (GT) and spin-dipole (SD) states in 208Bi are studied by using self-consistent Hartree-Fock + Tamm-Dancoff approximation taking into account the coupling to the
continuum. Most of SD strength is found at the excitation energy E
x≈ 25MeV with a very broad width, which agrees with recent experimental observations. It is shown that Landau damping effect is responsible
for the large width of SD peak, while the escape width is found to be at most 1MeV. We study also electric dipole (E1) transitions between GT and SD states in 208Bi. Main E1 transitions for 0- and 1- states are found near excitation energy expected from Brink's hypothesis in which SD states are considered as E1 resonances built on the GT state. Calculated E1 transition strengths between GT and SD states are compared with the analytic sum rules within one-particle one-hole (1p-1h)
configuration space and within both 1p-1h and 2p-2h model space.
Received: 11 April 2000 / Accepted: 30 August 2000 相似文献
15.
G. Baur C.A. Bertulani D. Dolci 《The European Physical Journal A - Hadrons and Nuclei》2000,7(1):55-58
We study the effect of the spreading widths on the excitation probabilities of the double giant dipole resonance. We solve
the coupled-channels equations for the excitation of the giant dipole resonance and the double giant dipole resonance. Taking
Pb+Pb collisions as example, we study the resulting effect on the excitation amplitudes, and cross sections as a function
of the width of the states and of the bombarding energy.
Received: 13 July 1999 相似文献
16.
R.R. Hilton W. Höhenberger P. Ring 《The European Physical Journal A - Hadrons and Nuclei》1998,1(3):257-260
Experimental observations in certain rare earth nuclei have established the presence of sizeable B(M1) strength of two peak
structure lying in the 5–10 MeV region. The character of the states concerned, studied within a self-consistent Random Phase
Approximation using Skyrme forces, are identified to be that of proton and neutron giant spin-flip resonances.
Received: 14 July 1997 / Revised version: 20 October 1997 相似文献
17.
J. Ekman D. Rudolph C. Fahlander R.J. Charity W. Reviol D.G. Sarantites V. Tomov R.M. Clark M. Cromaz P. Fallon A.O. Macchiavelli M. Carpenter D. Seweryniak 《The European Physical Journal A - Hadrons and Nuclei》2000,9(1):13-17
Eighteen previously unknown γ-ray transitions were identified in the T
z = - 1/2 nucleus 51Fe following the fusion-evaporation reaction 32S(28Si,2α1n)51Fe. The level scheme reaches the fully aligned I
π = 27/2- terminating state of the five holes in the f
7/2 shell. The 17/2- state was found to be isomeric, and the lifetime was measured to be 2.87 ns. The mirror symmetry of 51Fe and 51Mn is discussed, and the level scheme of 51Fe is compared to shell-model calculations.
Received: 20 July 2000 / Accepted: 1 August 2000 相似文献
18.
It is found here that the 1/2+ first excited state of 9Be is a virtual state with the energy of −23.5 KeV. The line shape for the excitation of the state is approximated with a
simple analytic form based on the effective range expansion. The partner in 9B of this state is found to be a resonance with a maximum in the peak at about 1.1 MeV, FWHM of 1.5 MeV, and complex energy
of 0.6 −i0.75 MeV. The line shape for its excitation is calculated in terms of the p−8Be phase shift. The phase shifts are obtained from N−8Be effective potentials deduced from the data on the photodisintegration of 9Be. A possibility for direct extraction of the energy of the resonant state from experimental data is also discussed, and
an expression for a residue at a virtual state pole in terms of a quadrature taken over the virtual state eigenfunction is
given.
Received: 23 March 1998 / Revised version: 3 September 1998 相似文献
19.
20.
B. Blank 《The European Physical Journal A - Hadrons and Nuclei》2002,15(1-2):121-124
In recent experiments at GANIL, we studied nuclei at the one- and two-proton drip line. The production rates allowed to search
for direct 2p emission in the drip line nuclei 42Cr, 45Fe, and 49Ni. No evidence for this decay mode was found in 42Cr and 49Ni, whereas the situation stays unclear for 45Fe due to the limited statistics. In the medium-mass region ( A = 50-70), the half-life was measured for all proton-rich nuclei in the range T
z = 0 to T
z = - 1 between Z = 27 and Z = 36. First half-lives were determined for 60Ga, 62Ge, 64As and 66Se. Finally, β-decay studies of the 0+ → 0+ decay of 62Ga have been performed at IGISOL in Jyv?skyl?. Non-analog transitions have been observed and are compared to theoretical predictions.
Received: 21 March 2002 / Accepted: 16 May 2002 / Published online: 31 October 2002
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ID="a"e-mail: blank@cenbg.in2p3.fr 相似文献