Search results for "EXCITATION"
showing 10 items of 1290 documents
RPA susceptibility of asymmetric nuclear matter at finite temperatures with Skyrme interactions
1997
Abstract We investigate the thermal RPA response of asymmetric nuclear matter interacting through various Skyrme interactions characterized by the value of the effective nucleon mass. Our study concentrates on the evolution of collective states according to the variations of the transferred momentum, temperature and asymmetry ratio. The differences and similarities between the roles of neutron excess and of thermal excitation are discussed. It is shown that the limit of meaningful nuclear asymmetries, namely Y close to 1/3, must be reached in order to observe sizable effects in the structure patterns, a fact that brings support to calculations of dynamical response that resort to symmetric …
Character of particle-hole excitations in94Ru deduced fromγ-ray angular correlation and linear polarization measurements
2014
Linear polarization and angular correlations of gamma-rays depopulating excited states in the neutron-deficient nucleus Ru-94(44)50 have been measured, enabling firm spin-parity assignments for several excited states in this nucleus. The deduced multipolarities of strong transitions in the yrast structure were found to be mostly of stretched M1, E1, and E2 types and, in most cases, in agreement with previous tentative assignments. The deduced multipolarity of the 1869 keV and the connecting 257 and 1641 keV transitions indicates that the state at 6358 keV excitation energy has spin parity 12(1)(-) rather than 12(3)(+) as proposed in previous works. The presence of a 12(1)(-) state is interp…
Identification of the 13/2+ isomer in 199At
2000
The 13/2+ isomeric state in the 199At nucleus has been identified at an excitation energy of 573 keV and its half-life measured to be 580(130) ns using the recoil-decay tagging technique.
On the NN-final-state-interaction in the $^{16}{O}(e,e' pp)$ reaction
2002
The influence of the mutual interaction between the two outgoing nucleons (NN-FSI) in the $^{16}{O}(e,e' pp)$ reaction has been investigated. Results for various kinematics are discussed. In general, the effect of NN-FSI depends on kinematics and the chosen final state in the excitation spectrum of $^{14}{C}$.
Spectroscopy at the two-proton drip line: Excited states in 158W
2017
Abstract Excited states have been identified in the heaviest known even-Z N = 84 isotone 158W, which lies in a region of one-proton emitters and the two-proton drip line. The observation of γ-ray transitions feeding the ground state establishes the excitation energy of the yrast 6+ state confirming the spin-gap nature of the α-decaying 8+ isomer. The 8+ isomer is also expected to be unbound to two-proton emission but no evidence for this decay mode was observed. An upper limit for the two-proton decay branch has been deduced as b 2 p ≤ 0.17% at the 90% confidence level. The possibility of observing two-proton emission from multiparticle isomers in nearby nuclides is considered.
Coulomb excitation of Na-29,Na-30: Mapping the borders of the island of inversion
2014
Seidlitz, M., et all ; 10 pags. ; 9 figs. ; 1 tab. ; PACS number(s): 21.60.Cs, 23.20.Js, 25.70.De, 29.38.Gj
Breakdown transient study of plasma distributions in a 2.45 GHz hydrogen discharge
2015
Plasma distribution transients associated with the breakdown of a 2.45 GHz hydrogen discharge similar to high current microwave ion sources are studied by means of an ultra-fast frame image acquisition system in visible light range. Eight different plasma distributions have been studied by photographing the 2D projections of the discharge through a transparent plasma electrode. The temporal evolution of images in Balmer-alpha and Fulcher band wavelengths have been recorded associated to atomic and molecular excitation and ionization processes. Some unexpected plasma distributions transient behaviors during breakdown are reported.
Schematic and realistic model calculations of the isovector spin monopole excitations in 116In
2012
The excitation of Gamow-Teller (GT) and isovector spin monopole (IVSM) Jπ=1+ modes in 116In by (p,n) and (n,p) charge-exchange reactions on 116Cd and on 116Sn, respectively, is studied within the framework of the quasiparticle random-phase approximation. The calculations have been performed both for schematic and realistic model situations. It appears that the calculated admixture of the IVSM and Gamow-Teller (GT) Jπ=1+ excitations is negligible and that the contribution to the strength above 20 MeV of excitation energy, in 116In, is due to the IVSM (σr2t ±) mode. This result is compared with the recent experimental work that reported a large amount of both (p,n) and (n,p) strength beyond 1…
Low-lying states in near-magic odd-odd nuclei and the effective interaction
2014
The iterative quasiparticle random-phase approximation (QRPA) method we previously developed [Phys. Rev. C 81, 034312 (2010); 86, 024303 (2012); 86, 014307 (2012)] to accurately calculate properties of individual nuclear states is extended so that it can be applied for nuclei with odd numbers of neutrons and protons. The approach is based on the proton-neutron QRPA (pnQRPA) and uses an iterative non-Hermitian Arnoldi diagonalization method where the QRPA matrix does not have to be explicitly calculated and stored. The method is used to calculate excitation energies of proton-neutron multiplets for several nuclei. The influence of a pairing interaction in the T = 0 channel is studied.
Interweaving of elementary modes of excitation in superfluid nuclei through particle-vibration coupling: Quantitative account of the variety of nucle…
2015
A complete characterization of the structure of nuclei can be obtained by combining information arising from inelastic scattering, Coulomb excitation, and $\ensuremath{\gamma}$-decay, together with one- and two-particle transfer reactions. In this way it is possible to probe both the single-particle and collective components of the nuclear many-body wave function resulting from the coupling of these modes and, as a result, diagonalizing the low-energy Hamiltonian. We address the question of how accurately such a description can account for experimental observations in the case of superfluid nuclei. Our treatment goes beyond the traditional approach, in which these properties are calculated …