Results 1 - 10 of 10871
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[en] The level structure of the 88-neutron nucleus 88156Er has been investigated from the EC and β+ decay of 156Tm (Tsub(1/2)=80s). Mass-separated samples were obtained from the Orsay on-line separator. Gamma-ray spectra, conversion electron spectra, and γ-γ bi-dimensional coincidences were performed by using semiconductor detectors. Members of the β- and γ-bands are proposed. The possible superposition of the 0+ β-level and the 2+ γ-level at 930-5 keV is discussed. (Auth.)
[en] The exclusive cross section for the breakup of 6Li by 209Bi has been measured at Elab=40 and 36 MeV. Sequential breakup, via the resonant state (3+) of 6Li in the continuum, dominates the total breakup cross section. The two sequential breakup peaks corresponding to the above resonant state, in both alpha and deuteron spectra, were found to be asymmetric. Continuum discretized coupled-channel (CDCC) calculations show the influence of both the Coulomb as well as the nuclear field on breakup.
[en] We determine primordial 7Li abundance independently of a previous method based on the measurement of the Spite plateau by using isotopic abundance ratios of 7Li/6Li in the interstellar media. The inferred best fit constraints on the primordial 7Li abundance is 7Li/H congruent with 2.5 x 10-10, and the conservative upper limit at the 95% confidence level turns out to be 7Li/H < 8 x 10-10
[en] We investigate qualitative and quantitative projectile resonance effects on breakup and total fusion cross sections of the breakup of 6Li on 144Sm target. We show that these resonances exhibit opposite and slightly pronounced effects on the integrated breakup cross sections than on total fusion cross sections. It is obtained that, for energies above the Coulomb barrier, breakup cross sections are increased by the inclusion of these resonances, while fusion cross sections are reduced. We deduced that, on average, above the barrier, breakup cross sections are increased by , whereas fusion cross sections are suppressed by in the presence of the resonances.
[en] Determination of accurate nuclear level densities is of crucial importance for a variety of pure and applied nuclear physics. The density of accessible levels is calculated for 166Er nucleus using the microscopic theory of interacting fermions and is compared with experimental data. It is shown that the data can be reproduced by a level density formalism developed for nuclei with static deformation. Our results are in a good agreement with the experimental data obtained by the Oslo group.
[en] The Friar-Negele method for deducing charge densities from electron scattering and muonic atom data is applied to determine the 209Bi-208Pb isotone shift. A comparison is made to the results of Hartree-Fock calculations. The core polarization is discussed in terms of a phenomenological model of the breathing mode. (Auth.)
[en] The delayed neutron spectrum following β- decay of the 4.17 sec 17N has been measured with high-resolution 3He spectrometers. The intensities of the neutron branches from levels in 17O at 4549.3 +- 1.3, 5081 +- 21, 5387.1 +- 1.2 and 5949.9 +- 1.9 keV excitation energy result in 17N β- transitions of (34.8 +- 2.6), (0.6 +- 0.4), (52.7 +- 3.5) and (7.0 +- 0.5)%, respectively. The neutron widths of these states were determined as 54.8 +- 0.4, 113 +- 55, 63.2 +- 1.1 and 60.5 +- 3.2 keV, respectively, in disagreement with previously reported values. The results are compared with theoretical calculations and with the mirror decay of 17Ne. (Auth.)
[en] The energy levels of 157Gd have been investigated using the (n, γ) and (n, n'γ) reactions. As a result of the analysis of the γ-ray spectra from 16 isolated neutron resonances, a level scheme with a complete set of levels with spins J=1/2, 3/2 has been established up to 1.86 MeV excitation energy. A part of the level scheme is interpreted in more detail on the basis of Coriolis and ΔN=2 coupled Nilsson configurations. Slightly different sets of shape parameters are deduced for negative- and positive-parity levels. A large excess of unassigned 1/2 and 3/2 levels evidently requires an explanation in terms of inclusion of new additional degrees of freedom
[en] In 1997 the joint-European γ-ray detector array JUROSPHERE was installed at RITU, the gas-filled separator for fusion products of JYFL, University of Jyvaeskylae (Finland). This combined detection system has proven to be a very powerful tool for spectroscopy studies of extremely neutron-deficient nuclei. Highlights of the new physics from JUROSPHERE and RITU include the first observation of excited states and/or γ-rays in 168,170-172Pt, 176Hg, 184,187Pb, 198,201Rn, 206,208,210Ra, 223Pa and 226U. In several other cases γ-ray spectroscopic knowledge could be extended to much higher spins, enabling the search for superdeformed states and shears bands