共查询到20条相似文献,搜索用时 31 毫秒
1.
N. de Séréville C. Angulo A. Coc N. L. Achouri E. Casarejos T. Davinson P. Descouvemont P. Figuera S. Fox F. Hammache J. Kiener A. Laird A. Lefebvre P. Leleux P. Mumby-Croft N. Orr D. Robertson K. Vaughan V. Tatischeff 《The European physical journal. Special topics》2007,150(1):211-214
The 18F, produced during nova explosions, is the main responsible
for the 511 keV γ-ray emitted during the outburst that could be detected
with satellite missions or future γ-ray telescopes. In spite of many
experimental efforts, the amount of 18F synthesized still suffers from large
uncertainties concerning mainly the 18F(p,α)15O reaction. We report here on a new
direct measurement of the 18F(p,α)15O cross section recently carried out at the RIB
facility at Louvain-la-Neuve. Cross section data down to a center-of-mass
energy of 400 keV have been obtained using an isobarically pure 18F beam
(averaged intensity of the order of 106 pps) and a thin polyethylene
target. The reaction products were detected using the multi-strip detector
array LEDA. The cross section data are analysed in the framework of the
R-matrix model. Our main aim is to determine the interference sign between
three 3/2+ resonances above threshold that can significantly affect the
extrapolation of the 18F(p,α)15O cross section to the energies relevant for novae,
and thus, the modeling of nova explosions. 相似文献
2.
G. Bollen C. Bachelet M. Block D. A. Davies M. Facina C. M. Folden III C. Guénaut J. Huikari E. Kwan A. Kwiatowski D. J. Morrissey G. Pang A. Prinke R. Ringle J. Savory P. Schury S. Schwarz C. Sumithrarachchi T. Sun 《The European physical journal. Special topics》2007,150(1):337-341
The Low-Energy Beam and Ion Trap facility LEBIT at the
NSCL at MSU has demonstrated that rare isotopes produced by
fast-beam fragmentation can be slowed down and prepared for
precision experiments with low-energy beams. High-pressure
gas-stopping was combined with advanced ion manipulation techniques
to carry out these studies with a high-precision 9.4-Tesla Penning
trap mass spectrometer. The spectrometer has been used for a series
of high precision mass measurements of short-lived neutron- and
proton-rich isotopes during the past year. This paper presents an
overview of the LEBIT facility and summarizes the first mass
measurement results. The mass measurements of 81Se, where
ground and isomeric states have been resolved, and of 80As will
be discussed in detail. 相似文献
3.
E. Bouquerel R. Catherall M. Eller J. Lettry S. Marzari T. Stora ISOLDE Collaboration 《The European physical journal. Special topics》2007,141(1):277-280
A new target and ion source unit has been developed at
CERN-ISOLDE with the aim of delivering isobarically clean beams of
short lived neutron-rich Cd and Zn. A quartz insert in the transfer
line allows the trapping and the decay of alkali contaminants. This
paper presents the design of the quartz transfer line. Alkali
suppression is demonstrated with 80Rb and 114Cs. The
yield of 8Li, 46K, 77Ga and 75Zn is presented. 相似文献
4.
We introduce a discrete model describing
the motion of a zigzag domain
wall in a disordered ferromagnet with in-plane
magnetization, driven by an external magnetic field. The main
ingredients are dipolar interactions and anisotropy.
We investigate the dynamic hysteresis by analyzing
the effects of external field frequency
on the coercive field by Monte Carlo
simulations. Our results are in
good agreement with experiments on
Fe/GaAs films reported in literature, and
we conclude that dynamic hysteresis
in this case can be explained by a single propagating domain
wall model without invoking domain nucleation. 相似文献
5.
K. Minamisono P. F. Mantica T. J. Mertzimekis A. D. Davies M. Hass J. Pereira J. S. Pinter W. F. Rogers J. B. Stoker B. E. Tomlin R. R. Weerasiri 《The European physical journal. Special topics》2007,150(1):145-146
The nuclear magnetic moment of the ground state of 57Cu(Iπ = 3/2-, T1/2 = 196.3 ms) has been measured to be |μ(57Cu)| = (2.00 ±0.05) μN using the β-NMR technique. Together with the known magnetic moment of the mirror partner 57Ni, the spin expectation value was extracted as
= -0.78 ± 0.13. Discrepancy between present results and shell model calculations in the full fp shell implies significant
shell breaking at 56Ni with the neutron number N = 28. 相似文献
6.
H. Geissel Yu. A. Litvinov K. Beckert P. Beller F. Bosch D. Boutin C. Brandau L. Chen M. Hausmann O. Klepper R. Knö bel C. Kozhuharov J. Kurcewicz S. A. Litvinov M. Mazzocco G. Münzenberg C. Nociforo F. Nolden Z. Patyk M. Pfü tzner W. Plaß C. Scheidenberger M. Steck B. Sun K. Takahashi H. Weick N. Winckler M. Winkler 《The European physical journal. Special topics》2007,150(1):109-115
High accuracy mass and lifetime measurements are
performed with the combination of the in-flight separator FRS and
the cooler-storage ring ESR at GSI. Exotic nuclei are produced via
projectile fragmentation and fission at (400–900) MeV/u. This
energy range is the basis for unique experimental conditions with
bare and few-electron fragments and allows for the first time
investigations for decay channels which are rare or strictly
forbidden in neutral atoms. New experimental developments and data
including the discovery of new isotopes are presented. The
comparison of the experimental results with theoretical
predictions indicates the potential for improvements of nuclear
models. A new generation of experiments will be possible with the
advent of the proposed international Facility for Antiproton and
Ion Research (FAIR). 相似文献
7.
R. Lichtenthäler P. N. de Faria A. Lépine-Szily V. Guimarães O. Camargo Jr. R. Denke E. A. Benjamim A. Barioni K. C.C. Pires D. J. Mendes M. Assunção A. Arazi I. Padron P. R.S. Gomes 《The European physical journal. Special topics》2007,150(1):27-30
A double superconducting solenoid system is installed
at the Pelletron Laboratory of the University of S?o Paulo, Brazil.
This system
allows the production of secondary beams of 8Li, 6He, 7Be and others light exotic nuclei.
The first results using this facility are presented. 相似文献
8.
9.
S. F. Ban L. S. Geng W. H. Long J. Meng J. Peng J. M. Yao S. Q. Zhang S. G. Zhou 《The European physical journal. Special topics》2007,150(1):139-144
The recent progress of the relativistic many-body approach
by the group at Peking University will be reviewed. In particular,
axially deformed relativistic Hartree-Bogoliubov approach in
Woods-Saxon basis aiming at halo nucleus, time-odd triaxial RMF
approach, the adiabatic and configuration-fixed constrained triaxial
RMF approaches, a Reflection ASymmetric RMF (RAS-RMF) approach, and
a new relativistic Hartree-Fock (RHF) approach with
density-dependent σ,ω,ρ and π meson-nucleon
couplings for finite nuclei and nuclear matter, will be highlighted. 相似文献
10.
《The European physical journal. Special topics》2007,150(1):173-176
First results are reported from a major new initiative of
experiments, which focus on nuclear structure studies at extreme isospin
values by means of isomer spectroscopy. The experiments represent the
first part of the so-called stopped-beam campaign within the Rare
ISotope INvestigations at GSI (Rising) project. Time-correlated
γ decays from individually identified nuclear species have been
measured, allowing the clean identification of isomeric decays in a wide
range of exotic nuclei both at the proton drip-line and in heavy, neutron-rich
systems. An overview of the experimental technique will be given, together
with the performance of the new germanium detector array and future research
plans for the collaboration. 相似文献
11.
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
12.
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
13.
P. Bricault 《The European physical journal. Special topics》2007,150(1):227-232
The ISAC facility at TRIUMF utilizes up to 100 μA from the 500 MeV H- cyclotron to produce the RIB using the Isotopic Separation On Line (ISOL) method. The ISAC-I facility comprised the RNB production
target stations, the mass separator and the beam delivery to low energy area and to a room temperature linear accelerator
composed of a 4-rod RFQ and an inter-digital H type structure Drift Tube LINAC. ISAC-I linear accelerator can provide beam
from A = 3 to 30 amu with an energy range from 0.15 to 1.5 A MeV.
Since the beginning of operations target development program has been to increase proton beam currents on targets. Now we
routinely operate our target at 50 to 85 μA and recently we have operated our target at 100 μA. Other developments are in
place to add other ion sources, laser, FEBIAD and ECRIS to the actual surface ion source. The last two five year plans were
mainly devoted to the construction of a heavy ion superconducting LINAC (ISAC-II), that will upgrade the mass and the energy
range from 30 to 150 and 1.5 to 6.5 A MeV, respectively.
We are now commissioning the medium β section and first experiment is scheduled for the fall 2006. 相似文献
14.
A. Gillibert A. Obertelli N. Alamanos M. Alvarez F. Auger R. Dayras A. Drouart G. de France B. Jurado N. Keeley V. Lapoux W. Mittig X. Mougeot L. Nalpas A. Pakou N. Patronis E. Pollacco F. Rejmund M. Rejmund P. Roussel-Chomaz H. Savajols F. Skaza Ch. Theisen 《The European physical journal. Special topics》2007,150(1):161-163
27Ne has been investigated through the one neutron transfer reaction 26Ne(d,p)27Ne in inverse
kinematics at 9.7 MeV/nucleon. The results support the existence of a low lying negative parity state
in 27Ne which is a signature of a reduced sd-fp shell gap in the N = 16 neutron rich region, at variance
with stable nuclei. 相似文献
15.
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
16.
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
17.
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
18.
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
19.
R. Crespo A. M. Moro I. J. Thompson M. Rodríguez-Gallardo J. Gómez-Camacho J. M. Arias 《The European physical journal. Special topics》2007,150(1):13-14
The p-6He inelastic scattering at 700 MeV u-1 is studied
using Multiple Scattering expansion
of the total Transition amplitude (MST)
framework with a pseudo-state representation of 6He continuum.
We show that the differential cross sections calculated
with two different pseudo-state bases are in good agreement. 相似文献
20.
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