共查询到20条相似文献,搜索用时 31 毫秒
1.
G. Benzoni F. Azaiez S. Leoni S. Battacharyya R. Borcea A. Bracco L. Corradi D. Curien G. De France Zs. Dombrádi E. Fioretto S. Franchoo S. Grevy F. Ibrahim S. Iulian G. Mukherjee A. Navin G. Pollarolo N. Redon P. H. Regan M. Rejmund C. Schmitt G. Sletten D. Sohler M. Stanoiu S. Szilner D. Verney 《The European physical journal. Special topics》2007,150(1):83-86
A study of deep-inelastic and multi-nucleon transfer reactions to populate neutron-rich
O, Ne and F nuclei is here presented. The reaction under analysis employed a beam of radioactive
24Ne at 7.9 AMeV, provided by the
SPIRAL facility at Ganil, impingin on a 208Pb target. The reaction products have been
detected in the VAMOS spectrometer in coincidence with gamma rays
measured by the EXOGAM array. Preliminary results here presented show a selectivity
in the population of states of different nature. 相似文献
2.
G. Neyens P. Himpe D. L. Balabanski P. Morel L. Perrot M. De Rydt I. Stefan C. Stodel J. C. Thomas N. Vermeulen D. T. Yordanov 《The European physical journal. Special topics》2007,150(1):149-153
This paper reviews recent results from electromagnetic
moment measurements on isotopes in the island of inversion around
N=20. The obtained moments on neutron rich Na, Mg, Al and Si
isotopes allow to draw conclusions on the amount of intruder
components in their ground state wave function, demonstrating a
gradual transition from the normal sd-shell region into the
island of inversion, starting at N=18 for Na, N=19 for Mg and N=20
for Al isotopes. A measurement of the ground state g factor of
35Si (N=21), using a polarized fragment beam at GANIL, is
discussed in more detail. The magnetic moment μ(35Si, Iπ= 7/2-) = (-)1.638(4) μN is consistent with a normal ground
state structure, dominated by a νf7/2 neutron. 相似文献
3.
D. T. Khoa 《The European physical journal. Special topics》2007,150(1):31-34
DWBA analysis of the inelastic 30-40S(p,p') and
18-22O(p,p') scattering data measured in the inverse kinematics has been
performed to determine the isoscalar (δ0) and isovector (δ1)
deformation lengths of the 2+1 excitations in the Sulfur and Oxygen isotopes
using a compact folding approach. A systematic N-dependence of δ0 and
δ1 has been established which shows a link between δ1 and the
neutron-shell closure. Strong isovector deformations were found in several
cases, e.g., the 2+1 state in 20O where δ1 is nearly three
times larger than δ0. These results confirm the relation
δ1>δ0 anticipated from the core polarization by the valence
neutrons in the open-shell (neutron rich) nuclei. The effect of neutron shell
closure at N=14 or 16 has been discussed based on the folding model analysis
of the inelastic 22O+p scattering data at 46.6 MeV/u measured recently at
GANIL. 相似文献
4.
R.R. Rodríguez-Guzmán J.L. Egido L.M. Robledo 《The European Physical Journal A - Hadrons and Nuclei》2003,17(1):37-47
The Angular Momentum Projected Generator Coordinate Method, with the quadrupole moment as collective coordinate and the Gogny
force (D1S) as the effective interaction, is used to describe the properties of the ground state and low-lying excited states
of the even-even neon isotopes 20-34Ne, that is, from the stability valley up to the drip line. It is found that the ground state of the N = 20 nucleus 30Ne is deformed but to a lesser extent than the N = 20 isotope of the magnesium. In the calculations, the isotope 32Ne is at the drip line in good agreement with other theoretical predictions. On the other hand, rather good agreement with
experimental data for many observables is obtained.
Received: 19 Novemeber 2002 / Accepted: 24 January 2003 / Published online: 8 April 2003 相似文献
5.
W. von Oertzen 《The European Physical Journal A - Hadrons and Nuclei》2001,11(4):403-411
Using the concept of covalent molecular orbitals for neutrons and the known properties of the local α + 16O potential the formation of asymmetric molecular structures in neon isotopes is discussed. Experimental evidence for parity doublets in 21Ne is reviewed and a corresponding band structure for the states in 21Ne at moderate excitation energy of E
x = 0-8 MeV is proposed. The structure of some bands can be interpreted as consisting of an instrinsic asymmetric ( 4He + 16O) structure bound by a covalent neutron in σ and π orbitals. An extension of the observed structures to symmetric molecular structures in isotopes of Mg and heavier nuclei is suggested. In particular shape isomers in isotopes of magnesium, namely (He)2O molecules, can be predicted and an extended Ikeda diagram is proposed.
Received: 11 July 2001 / Accepted: 22 August 2001 相似文献
6.
I. Hamamoto 《The European physical journal. Special topics》2007,150(1):123-126
Both
positive-energy and weakly-bound one-particle levels for neutrons in
Y20 deformed Woods-Saxon potentials are examined in comparison with those
in spherical Woods-Saxon potentials.
While s1/2 levels play a unique role in spherical drip-line nuclei,
the Ωπ = 1/2+ levels in Y20 deformed potentials,
which always contain some amount of s1/2 component, exhibit an
important role in deformed drip-line nuclei.
As the potential strength becomes weaker, some weakly-bound
Ωπ = 1/2+ levels continue to the positive-energy region as
one-particle resonant levels, while others have no such continuation.
Among an infinite number of one-particle levels at a given positive-energy
and in a given deformed potential, only some selected levels expressed
in terms of eigenphase
are found to be important in the pair-correlated ground state of
neutron-drip-line nuclei. 相似文献
7.
Isoscalar and isovector nuclear matter properties
are investigated in the
Skyrme Hartree-Fock (SHF) and the relativistic mean field (RMF) models.
The Skyrme parameters are related analytically to the isoscalar and the
isovector nuclear matter properties of the Hamiltonian density.
Linear correlations are found among the isovector nuclear matter properties of
the Hamiltonian density in both the SHF and the RMF models.
We also discovered that the correlations between the isovector properties
and the incompressibility K show a singularity at the critical
incompressibility Kc=306 MeV.
It is shown that the neutron skin thickness gives crucial
information about not only
for the neutron EOS but also about the isovector nuclear matter properties and
about the parameterization of Skyrme interaction.
Charge exchange spin-dipole (SD) excitations are
proposed to determine the neutron skin thickness model independently. 相似文献
8.
Guangyi Zhao Yunzuo Liu Jingbin Lu Yingjun Ma Lichang Yin Xianfeng Li Zhihuan Li Xiaoguang Wu Guangsheng Li Shuxian Wen Chunxiang Yang 《The European Physical Journal A - Hadrons and Nuclei》2000,9(3):299-302
It is shown that the discrepancy between the results obtained for different neutron energy ranges, when neutron polarizability is derived from the neutron scattering data, can be removed if one assumes that at the fast neutron scattering a strong-interaction long-range potential of Van der Waals (~ r ?6 ) or Casimir-Polder (~ r ?7 ) is observed. This strong-interaction long-range potential has possibly some experimental confirmation in the elastic p-p scattering. 相似文献
9.
10.
J. Benlliure P. Armbruster M. Bernas C. Böckstiegel S. Czajkowski C. Donzaud H. Geissel A. Heinz C. Kozhuharov P. Dessagne G. Münzenberg M. Pfützner C. Stéphan K.-H. Schmidt K. Sümmerer W. Schwab L. Tassan-Got B. Voss 《The European Physical Journal A - Hadrons and Nuclei》1998,2(2):193-198
Projectile fragmentation of 238U in a lead target was investigated at a bombarding energy of 750 A MeV. Isotopic production cross sections of about 250 different projectile fragments in the element range Z= 30–53 were measured with the FRagment Separator (FRS). The magnetic selection and the kinematical analysis of the measured
isotopes allowed to disentangle fission and fragmentation residues. The mass loss of these residues indicates a violent collision
where a large amount of energy is dissipated. The position of the fragmentation corridor defined by the measured residues
was used to determine an effective proton-evaporation barrier.
Received: 3 October 1997 / Revised version: 27 February 1998 相似文献
11.
X.H. Zhou M. Oshima Y. Toh Y.H. Zhang Y. Zheng M. Koizumi A. Osa T. Hayakawa Y. Hatsukawa T. Shizuma M. Sugawara 《The European Physical Journal A - Hadrons and Nuclei》2002,15(3):285-289
Based on the systematic investigation of the data available for nuclei with A≥ 40, a Z
1/3-dependence for the nuclear charge radii is shown to be superior to the generally accepted A
1/3 law. A delicate scattering of data around R
c/Z
1/3 is inferred as owing to the isospin effect and a linear dependence of R
c/Z
1/3 on N/Z (or (N - Z)/2) is found. This inference is well supported by the microscopic Relativistic Continuum Hartree-Bogoliubov (RCHB) calculation
conducted for the proton magic Ca, Ni, Zr, Sn and Pb isotopes including the exotic nuclei close to the neutron drip line.
With the linear isospin dependence provided by the data and RCHB theory, a new isospin-dependent Z
1/3 formula for the nuclear charge radii is proposed.
Received: 23 September 2001 / Accepted: 21 January 2002 相似文献
12.
M.?Madurga M. J.G.?Borge H. O.U.?Fynbo B.?Jonson G.?Nyman Y.?Prezado K.?Riisager O.?Tengblad IS-?collaboration TONERRE?collaboration 《The European physical journal. Special topics》2007,150(1):137-138
The aim of this work is to find out the origin of the anomalous
resonance in 8Be seen in the reactions through excited states in 9Be.
We have populated the 9Be excited states by β-decay of 9Li.
Energy and direction of the two α particles has been detected and the
neutron spectra reconstructed. In our work we identified the “anomalous resonance" in
8Be observed in several reaction studies
as coming from the decay of the 2.43 and 2.78 MeV states in 9Be.
This anomalous resonance appears when
the two detected α particles are assumed to form a resonance in 8Be.
We argued that the main decaying channels for these two levels in 9Be do not involve
8Be. 相似文献
13.
Low energy single nucleon transfer reactions are proposed as a tool to investigate the structure of nuclei far off stability.
Experimental concepts and conditions are discussed, in particular high resolution γ-ray spectroscopy after single nucleon
pickup reactions. Nuclear structure is described by Skyrme Hartree-Fock calculations including pairing. As representative
examples, binding energies, radii and wave functions for Mg and Sn isotopes are calculated. In the neutron deficient Mg isotopes
a proton skin is found. At the neutron driplines the Mg and Sn isotopes develop extended neutron skins. The nuclear structure
results are used in DWBA and EFR-DWBA transfer calculations. Single nucleon transfer reactions of 32,36Mg and exotic Sn beams on targets ranging from 2H to 24Mg in inverse kinematics are explored. The one-nucleon transfer cross sections decrease strongly for high-Z targets. An impact
parameter analysis shows that the transfer process is selective on the tails of the wave functions. The largest cross sections
are obtained for 2H and 9Be targets at incident energies of E
lab
= 2-5 MeV/u. The energy-momentum dependence is closely related to the special properties of wave functions of weakly bound
states. Two-neutron (p,t) stripping reactions are studied for a 6He projectile. A strong competition of sequential and direct processes is found at low energies.
Received: 1 October 1997 / Revised version: 25 November 1997 相似文献
14.
I. Dillmann M. Hannawald U. Köster V.N. Fedoseyev A. Wöhr B. Pfeiffer D. Fedorov J. Shergur L. Weissman W.B. Walters K.-L. Kratz 《The European Physical Journal A - Hadrons and Nuclei》2002,13(3):281-284
Production yields and β-decay half-lives (T
1/2) of very neutron-rich indium isotopes were determined at CERN/ISOLDE using isobaric selectivity of a resonance-ionization
laser ion-source. Beta-delayed neutron (βdn) multiscaling measurements have yielded improved T
1/2 for 206(6) ms 132In, 165(3) ms 133In and 141(5) ms 134In. With 92(10) ms 135In, a new r-process nuclide has been identified which acts as an important “waiting point” in the In isotopic chain for neutron
densities in the range n
n≃ 1024-1026 n/cm3, where the r-matter flow has already passed the A≃ 130 abundance peak region.
Received: 17 January 2002 / Accepted: 30 January 2002 相似文献
15.
T. Grahn A. Dewald O. Möller R. Julin C. W. Beausang S. Christen I. G. Darby S. Eeckhaudt P. T. Greenlees A. Görgen K. Helariutta J. Jolie H. Kettunen T. Kröll R. Krücken P. Jones S. Juutinen Y. Le Coz M. Leino A.-P. Leppänen P. Maierbeck B. Melon D. A. Meyer P. Nieminen M. Nyman R. Page J. Pakarinen P. Petkov P. Rahkila B. Saha M. Sandzelius J. Sarén C. Scholey J. Uusitalo 《The European physical journal. Special topics》2007,150(1):121-122
Lifetimes of low-lying yrast states in 186Pb and
194Po have been determined by employing, for the first time, the recoil-decay tagging technique in recoil distance Doppler-shift
lifetime measurements. In addition, lifetime measurements of prolate states in 188Pb up to the 8+ state were carried out using the recoil gating method. The deformation parameters
and
for the prolate (186,188Pb) and the oblate (194Po) bands,
respectively, have been extracted from the measured lifetimes.
27.70.+q– 相似文献
16.
H. Ogawa K. Asahi H. Ueno K. Sakai H. Miyoshi D. Kameda T. Suzuki H. Izumi N. Imai Y.X. Watanabe K. Yoneda N. Fukuda H. Watanabe A. Yoshimi W. Sato N. Aoi M. Nagakura T. Suga K Yogo A. Goto T. Honda Y. Kobayashi W.-D. Schmidt-Ott G. Neyens S. Teughels A. Yoshida T. Kubo M. Ishihara 《The European Physical Journal A - Hadrons and Nuclei》2002,13(1-2):81-85
The electric quadrupole moment of 17B and the g-factor of 17C were measured by using the fragmentation-induced nuclear polarization technique combined with the β-NMR method. The experimental
quadrupole moment of 17B is found strikingly close to that of the neutron closed-shell isotope 13B, indicating a strong quenching of the neutron E2 core-polarization charge. From the result obtained for the 17C g-factor, we can conclude that the ground-state spin-parity of 17C is 3/2+.
Received: 1 May 2001 / Accepted: 4 December 2001 相似文献
17.
Y.-J. Ma Y.-Z. Liu H.-B. Sun S. Wen S.-G. Zhou H. Zheng H.-T. Yang J.-D. Huo X.-G. Wu C.-X. Yang 《The European Physical Journal A - Hadrons and Nuclei》1998,2(1):21-23
Three new bands in 174Ta have been identified by using the 160Gd(19F,5n) reaction at beam energies of 87 MeV and 96 MeV. Nilsson configurations are assigned to these bands. In the 9/2−[514]p+5/2−[512]n band, the AB neutron crossing occurs at a rotational frequency of 0.30 MeV. This is indicative of the disappearance of the
evidence for a reduction in neutron pair correlations.
Received: 30 March 1998 相似文献
18.
Z.G. Gan Z. Qin H.M. Fan X.G. Lei Y.B. Xu J.J. He H.Y. Liu X.L. Wu J.S. Guo X.H. Zhou S.G. Yuan G.M. Jin 《The European Physical Journal A - Hadrons and Nuclei》2001,10(1):21-25
An isotope of the element 105 with mass number 259 has been produced via the reaction 241Am(22Ne, 4n)259Db at E
lab = 118 MeV. The reaction products were transported and collected using the helium-jet technique and the rotating wheel apparatus.
The α-decays of the products and their daughter nuclides were detected by a set of Si(Au) detectors arranged ingeniously.
The Z and A of the nuclide have been unambiguously identified by the genetic relationship between the new activity and the known nuclide
255Lr established by α-recoiled milking measurement. The new nuclide 259Db has a half-life of 0.51±0.16 s and decays by alpha-particle emission of E
α = 9.47 MeV. Furthermore, the nuclide 258Db and its daughter 254Lr have also been clearly observed using the same projectile-target combination. Their half-lives and α-particle energies
determined in this work are in agreement with previous known data, thus also proving the reliability of our assignment of
259Db.
Received: 7 December 2000 / Accepted: 6 February 2001 相似文献
19.
R. Krücken Z. Wang S.J. Asztalos J.A. Becker L.A. Bernstein R.M. Clark M.A. Deleplanque R.M. Diamond P. Fallon N. Fotiades K. Hauschild I.Y. Lee A.O. Macchiavelli G.J. Schmid F.S. Stephens K. Vetter 《The European Physical Journal A - Hadrons and Nuclei》1999,5(4):367-370
Lifetimes of states in the two strongest superdeformed (SD) bands in 193Tl were measured using the Doppler-shift attenuation method. The reaction 176Yb(23Na,6n)193Tl at a beam energy of 129 MeV was used and γ-rays were detected by the Gammasphere array. Quadrupole moments of 18.3(10)
eb and 17.4(10) eb were extracted for SD bands 1 and 2, respectively, using the fractional Doppler-shifts of the SD transitions.
The previously reported linking transitions of these SD bands to normal deformed near yrast levels could not be confirmed.
No other candidates for linking transitions could be established.
Received: 27 April 1999 相似文献
20.
Careful review of all the evidence makes it clear that at least three states are important at 12.4-MeV excitation in 20Ne (four, if the broad (2+) at 12.5 MeV is included). The three states are 3 - , 0 + , and 1 + (0+). The latter, which is quite strong in 19F (3He, d) singles, is probably the state observed in coincidence with 6.13-MeV γ-rays in 19F(3He, dγ).
Received: 19 August 2002 / Accepted: 28 October 2002 / Published online: 17 January 2003
RID="a"
ID="a"e-mail: fortune@physics.upenn.edu
Communicated by D. Guerreau 相似文献