共查询到20条相似文献,搜索用时 31 毫秒
1.
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
2.
Yu.Ts. Oganessian A.V. Yeremin G.G. Gulbekian S.L. Bogomolov V.I. Chepigin B.N. Gikal V.A. Gorshkov M.G. Itkis A.P. Kabachenko V.B. Kutner A.Yu. Lavrentev O.N. Malyshev A.G. Popeko J. Roháč R.N. Sagaidak S. Hofmann G. Münzenberg M. Veselsky S. Saro N. Iwasa K. Morita 《The European Physical Journal A - Hadrons and Nuclei》1999,5(1):63-68
The reaction 48Ca+238U was investigated at the recoil separator VASSILISSA at the Flerov Laboratory of Nuclear Reactions, JINR Dubna, in attempts
to synthesize new isotopes of element 112. The experiments were performed at two beam energies resulting in excitation energies
of the compound nucleus of 33 and 39 MeV. The collected beam dose was 3.5 × 1018 and 2.2 × 1018, respectively. Two spontaneous fission events were observed at the lower beam energy, which tentatively were assigned to
the new neutron rich isotope 283112 produced in the reaction 238U(48Ca,3n)283112. The measured cross-section is (5.0+6.3
−3.2) pb and the half–life is (81+147
−32) s. No event was observed at the higher beam energy resulting in the upper cross–section limit of 7.3 pb.
Received: 12 October 1998 / Revised version: 12 January 1999 相似文献
3.
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
4.
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
5.
J. Becker H.G. Andresen J.R.M. Annand K. Aulenbacher K. Beuchel J. Blume–Werry Th. Dombo P. Drescher M. Ebert D. Eyl A. Frey P. Grabmayr T. Großmann P. Hartmann T. Hehl W. Heil C. Herberg J. Hoffmann J.D. Kellie F. Klein K. Livingston M. Leduc M. Meyerhoff H. Möller Ch. Nachtigall A. Natter M. Ostrick E.W. Otten R.O. Owens S. Plützer E. Reichert D. Rohe M. Schäfer H. Schmieden R. Sprengard M. Steigerwald K.-H. Steffens R. Surkau Th. Walcher R. Watson E. Wilms 《The European Physical Journal A - Hadrons and Nuclei》1999,6(3):329-344
The electric form factor of the neutron GEn has been determined in double polarized exclusive 3
He(e,e'n) scattering in quasi–elastic kinematics by measuring asymmetries A
⊥, A
∥ of the cross section with respect to helicity reversal of the electron, with the nuclear spin being oriented perpendicular
to the momentum transfer q in case of A⊥ and parallel in case of A∥. The experiment was performed at the 855 MeV c. w. microtron MAMI at Mainz. The degree of polarization of the electron beam
and of the gaseous 3
He target were each about 50%. Scattered electrons and neutrons were detected in coincidence by detector arrays covering large
solid angles. Quasi–elastic scattering events were reconstructed from the measured electron scattering angles ϑe, φe and the neutron momentum vector p
n
′ in the plane wave impulse approximation. We obtain the result <G
En>(0.27 < Q2c2/GeV2 < 0.5)= 0.0334 ± 0.0033stat± 0.0028syst which is averaged over the indicated range of Q
2, the squared momentum transfer. This G
En value is significantly smaller than measured from the D(e,e'n) reaction under similar kinematical conditions. To what extent final state interactions in 3He quench the G
En result is subject of calculations currently in progress elsewhere.
Received: 29 April 1999 相似文献
6.
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
7.
Xie Yuanxiang Xu Shuwei Li Zhankui Yu Yong Pan Qiangyan Wang Chunfang Zhang Tianmei 《The European Physical Journal A - Hadrons and Nuclei》1999,5(3):239-241
Excited levels in 133Sn and 134Sb, populated in spontaneous fission of 248Cm, were studied by means of prompt-γ spectroscopy, using the EUROGAM 2 multidetector array. The neutron i
13/2 single-particle energy has been determined for the first time in the 132Sn region. The energy of the h
9/2 neutron level, proposed previously, has been confirmed.
Received: 13 January 1999 / Revised version: 22 March 1999 相似文献
8.
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
9.
H.A. Roth S.E. Arnell D. Foltescu Ö. Skeppstedt J. Blomqvist G. de Angelis D. Bazzacco S. Lunardi 《The European Physical Journal A - Hadrons and Nuclei》2001,10(3):275-287
High-spin level schemes of the N = 80 isotones 146Dy, 147Ho and 148Er have been investigated by in-beam γ-ray spectroscopic methods using the NORDBALL Compton-suppressed multidetector array
including proton and neutron selection. The projectile-target system 58Ni + 92Mo at 260 MeV beam energy has been used to produce the neutron-deficient N = 80 isotones. The previously known schemes have been extended to considerably higher spin and exitation energy, up to I = 23?, E
x≈ 8.9 MeV in 146Dy, I = 53/2?, E
x≈ 8.7 MeV in 147Ho and I = 23?, E
x≈ 9.6 MeV in 148Er. The results are discussed in terms of the spherical shell model. Many of the levels can be described within this framework.
Received: 12 January 2001 / Accepted: 11 April 2001 相似文献
10.
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
11.
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
12.
C. Gund H. Bauer J. Cub A. Dietrich T. Härtlein H. Lenske D. Pansegrau A. Richter H. Scheit G. Schrieder D. Schwalm 《The European Physical Journal A - Hadrons and Nuclei》2001,10(1):85-95
As a tool for studying the structure of nuclei far off stability the technique of γ-ray spectroscopy after low-energy single-nucleon
transfer reactions with radioactive nuclear beams in inverse kinematics was investigated. Modules of the MINIBALL germanium
array and a thin position-sensitive parallel plate avalanche counter (PPAC) to be employed in future experiments at REX-ISOLDE
were used in a test experiment performed with a stable 36S beam on deuteron and 9Be targets. It is demonstrated that the Doppler broadening of γ lines detected by the MINIBALL modules is considerably reduced
by exploiting their segmentation, and that for beam intensities up to 106 particles/s the PPAC positioned around zero degrees with respect to the beam axis allows not only to significantly reduce
the γ background by requiring coincidences with the transfer products but also to control the beam and its intensity by single
particle counting. The predicted large neutron pickup cross-sections of neutron-rich light nuclei on 2H and 9Be targets at REX-ISOLDE energies of 2.2 MeV .
A are confirmed.
Received: 9 October 2000 / Accepted: 28 January 2001 相似文献
13.
M. Oinonen U. Köster J. Äystö V. Fedoseyev V. Mishin J. Huikari A. Jokinen A. Nieminen K. Peräjärvi A. Knipper G. Walter 《The European Physical Journal A - Hadrons and Nuclei》2001,10(2):123-127
Beta-decay of 59Mn has been studied at PSB-ISOLDE, CERN. The intense and pure Mn beam was produced using the Resonance Ionization Laser Ion
Source (RILIS). Based on the measured β-decay rates the ground-state spin and parity are proposed to be J
π = 5/2-. This result is consistent with the systematic trend of the odd-A Mn nuclei and extends the systematics one step further towards the neutron drip line.
Received: 17 November 2000 / Accepted: 16 February 2001 相似文献
14.
M. Rejmund K.H. Maier R. Broda B. Fornal M. Lach J. Wrzesiński J. Blomqvist A. Gadea J. Gerl M. Górska H. Grawe M. Kaspar H. Schaffner C. Schlegel R. Schubart H.J. Wollersheim 《The European Physical Journal A - Hadrons and Nuclei》1998,1(3):261-266
High spin states in nuclei around 208Pb were populated in deep inelastic collisions of 76Ge, 136Xe, and 208Pb projectiles with 208Pb targets at beam energies about 12% above the Coulomb barrier. New states in 209Pb were found by measuring γ-γ-coincidences. They are interpreted as the yrast states that originate from the coupling of
one neutron to the lowest excitations of the 208Pb core. The results are discussed in the frame of the shell model.
Received: 22 November 1997 相似文献
15.
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
16.
N. Cavadini Th. Strässle P. Allenspach P.C. Canfield Ph. Bourges 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,29(3):377-384
The magnetic excitations in the antiferromagnetic phase of HoNi2B2C are studied by inelastic neutron scattering on single crystals for the first time. Spectra measured at constant T
= 2 K along symmetry directions of the reciprocal space are well explained in terms of crystal electric field (CEF) magnetic
excitons within the J
= 8 ground state multiplet of Ho3+. Very modest bandwidth with planar energy dispersion describes the magnetic exciton dynamics. A perturbative model approach
consisting of the CEF states in the effective exchange mean-field provides a simple but applicable characterization of the
experimental observations. The microscopic determination of the relevant exchange parameters is discussed in connection with
previous works on the subject.
Received 25 February 2002 / Received in final form 13 May 2002 Published online 14 October 2002
RID="a"
ID="a"e-mail: nordal.cavadini@psi.ch 相似文献
17.
A. Gopalan J. Bömmels S. Götte A. Landwehr K. Franz M.-W. Ruf H. Hotop K. Bartschat 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,22(1):17-29
A novel electron scattering apparatus for high resolution studies of angle-differential elastic and inelastic electron scattering
from atoms and molecules in the gas phase is described and its performance characterized. It combines a laser photoelectron
source, a triply differentially pumped collimated supersonic beam target (half angle 0.015 rad, background to beam density
ratio < 0.01), and several electron multipliers for simultaneous detection of elastically scattered electrons and metastable atoms (or
molecules) due to inelastic scattering. In detailed test measurements of the yield for the production of metastable He*(23S1) atoms around its threshold, the dependence of the overall energy width on various experimental parameters has been investigated.
So far a resolution down to 7 meV (FWHM) has been obtained. Under such conditions we have investigated the profile of the
He- (1
s
2
s
2
2
S
1/2
) resonance at the scattering angles 22
°
, 45
°
, and 90
°
. From a consistent fit of the measured profiles by resonant scattering theory we determine a new value for the resonance
energy ( E
r
= 19.365(1) eV) and an accurate resonance width ( Γ = 11.2(5) meV). These results are consistent with the previously recommended values.
Received 23 July 2002 Published online 29 October 2002
RID="a"
ID="a"e-mail: hotop@physik.uni-kl.de
RID="b"
ID="b"Permanent address: Department of Physics and Astronomy, Drake University, Des Moines, IA 50311, USA. 相似文献
18.
S. Heinz E. Berdermann F. Heine O. Joeres P. Kienle I. Koenig W. Koenig C. Kozhuharov U. Leinberger M. Rhein A. Schröter H. Tsertos 《The European Physical Journal A - Hadrons and Nuclei》1998,1(1):27-37
We present the results of a Doppler-shift correction to the measured e+e−–sum-energy spectra obtained from e+e−–coincidence measurements in 238U +206Pb and 238U +181Ta collisions at beam energies close to the Coulomb barrier, using an improved experimental setup at the double-Orange spectrometer
of GSI. Internal-Pair-Conversion (IPC) e+e− pairs from discrete nuclear transitions of a moving emitter have been observed following Coulomb excitation of the 1.844
MeV (E1) transition in 206Pb and neutron transfer to the 1.770 MeV (M1) transition in 207Pb. In the collision system 238U +181Ta, IPC transitions were observed from the Ta-like as well as from the U-like nuclei. In all systems the Doppler-shift corrected
e+e−–sum-energy spectra show weak lines at the energies expected from the corresponding γ–ray spectra with cross sections being
consistent with the measured excitation cross sections of the γ lines and the theoretically predicted IPC coefficients. No
other than IPC e+e−–sum-energy lines were found in the measured spectra. The transfer cross sections show a strong dependence on the distance
of closest approach (Rmin), thus signaling also a strong dependence on the bombarding energy close to the Coulomb barrier.
Received: 22 July 1997 / Revised version: 15 October 1997 相似文献
19.
M. Keim U. Georg A. Klein R. Neugart M. Neuroth S. Wilbert P. Lievens L. Vermeeren B. A. Brown 《The European Physical Journal A - Hadrons and Nuclei》2000,8(1):31-40
The nuclear electric quadrupole moments of the isotopes 26Na, 27Na, 28Na and 29Na were measured by -NMR spectroscopy in single crystals of LiNbO3 and NaNO3. High degrees of nuclear polarization were produced by optical pumping of the sodium atoms in a fast beam with a collinear
laser beam. The polarized nuclei were implanted into the crystals and NMR signals were observed in the -decay asymmetries. Preparatory measurements also yielded improved values for the magnetic moments of 27-31Na and confirmed the spin I=3/2 for 31Na. The results are discussed in comparison with large-basis shell model calculations.
Received: 1 February 2000 / Accepted: 3 April 2000 相似文献
20.
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