173 research outputs found
Nuclear structure and reaction studies at SPIRAL
The SPIRAL facility at GANIL, operational since 2001, is described briefly.
The diverse physics program using the re-accelerated (1.2 to 25 MeV/u) beams
ranging from He to Kr and the instrumentation specially developed for their
exploitation are presented. Results of these studies, using both direct and
compound processes, addressing various questions related to the existence of
exotic states of nuclear matter, evolution of new "magic numbers", tunnelling
of exotic nuclei, neutron correlations, exotic pathways in astrophysical sites
and characterization of the continuum are discussed. The future prospects for
the facility and the path towards SPIRAL2, a next generation ISOL facility, are
also briefly presented.Comment: 48 pages, 27 figures. Accepted for publication in Journal of Physics
Statistical properties of the well deformed Sm nuclei and the scissors resonance
The Nuclear Level Densities (NLDs) and the -ray Strength Functions
(SFs) of Sm have been extracted from (d,p)
coincidences using the Oslo method. The experimental NLD of Sm is
higher than the NLD of Sm, in accordance with microscopic calculations.
The SFs of Sm are in fair agreement with QRPA calculations
based on the D1M Gogny interaction. An enhancement is observed in the
SF for both Sm nuclei around 3 MeV in excitation energy and
is attributed to the M1 Scissors Resonance (SR). Their integrated strengths
were found to be in the range 1.3 - 2.1 and 4.4 - 6.4 for
Sm and Sm, respectively. The strength of the SR for Sm
is comparable to those for deformed even-even Sm isotopes from nuclear
resonance fluorescence measurements, while that of Sm is lower than
expected
Evolution of the -ray strength function in neodymium isotopes
The experimental gamma-ray strength functions (gamma-SFs) of 142,144-151Nd
have been studied for gamma-ray energies up to the neutron separation energy.
The results represent a unique set of gamma-SFs for an isotopic chain with
increasing nuclear deformation. The data reveal how the low-energy enhancement,
the scissors mode and the pygmy dipole resonance evolve with nuclear
deformation and mass number. The data indicate that the mechanisms behind the
low-energy enhancement and the scissors mode are decoupled from each other.Comment: 14 pages and 10 figure
Understanding the Low-Energy Enhancement of the -ray Strength Function of Fe
A model-independent technique was used to determine the -ray Strength
Function (SF) of Fe down to -ray energies less than 1
MeV for the first time with GRETINA using the reaction at 16 MeV. No
difference was observed in the energy dependence of the SF built on
and final states, supporting the Brink hypothesis. In addition,
angular distribution and polarization measurements were performed. The angular
distributions are consistent with dipole radiation. The polarization results
show a small bias towards magnetic character in the region of the enhancement
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