46 research outputs found
Study of Deformation Effects in the Charged Particle Emission from 46Ti
The 46Ti compound nucleus, as populated by the fusion-evaporation reaction
27Al + 19F at the bombarding energy of 144 MeV, has been investigated by
charged particle spectroscopy using the multidetector array ICARE at the
VIVITRON tandem facility of the IReS (Strasbourg). The light charged particles
have been measured in coincidence with evaporation residues. The CACARIZO code,
a Monte Carlo implementation of the statistical-model code CASCADE, has been
used to calculate the spectral shapes of evaporated alpha-particles which are
compared with the experimental spectra. This comparison indicates the possible
signature of large deformations of the compound nucleus.Comment: 6 pages, 4 figures, Proceedings od the Zakopane 20004 Symposium, to
be published in Acta Phys. Pol. B36 (2005
GDR Feeding of the Highly-Deformed Band in 42Ca
The gamma-ray spectra from the decay of the GDR in the compound nucleus
reaction 18O+28Si at bombarding energy of 105 MeV have been measured in an
experiment using the EUROBALL IV and HECTOR arrays. The obtained experimental
GDR strength function is highly fragmented, with a low energy (10 MeV)
component, indicating a presence of a large deformation and Coriolis effects.
In addition, the preferential feeding of the highly-deformed band in 42Ca by
this GDR low energy component is observed.Comment: 6 pages, 2 figures, Proceedings of the Zakopane2004 Symposium, to be
published in Acta Phys. Pol. B36 (2005
Strong Deformation Effects in Hot Rotating 46Ti
Exotic-deformation effects in 46Ti nucleus were investigated by analysing the
high-energy gamma-ray and the alpha-particle energy spectra. One of the
experiments was performed using the charged-particle multi-detector array ICARE
together with a large volume (4"x4") BGO detector. The study focused on
simultaneous measurement of light charged particles and gamma-rays in
coincidence with the evaporation residues. The experimental data show a
signature of very large deformations of the compound nucleus in the Jacobi
transition region at the highest spins. These results are compared to data from
previous experiments performed with the HECTOR array coupled to the EUROBALL
array, where it was found that the GDR strength function is highly fragmented,
strongly indicating a presence of nuclei with very large deformation.Comment: 10 pages, 6 figures, Proceedings of the Zakopane Conference on
Nuclear Physics, to be published in Acta Phys. Pol. B (2007
Deformation Effects in Hot Rotating 46Ti Probed by the Charged Particle Emission and GDR gamma-Decay
The 46Ti* compound nucleus, as populated by the fusion-evaporation reaction
27Al+19F at the bombarding energy of E_lab=144 MeV, has been investigated by
charged particle spectroscopy using the multidetector array ICARE at the
VIVITRON tandem facility of the IReS (Strasbourg). The light charged particles
and high-energy gamma-rays from the GDR decay have been measured in coincidence
with selected evaporation residues. The CACARIZO code, a Monte Carlo
implementation of the statistical-model code CASCADE, has been used to
calculate the spectral shapes of evaporated alpha-particles which are compared
with the experimental coincident spectra. This comparison indicates the
signature of large deformations (possibly superdeformed and hyperdeformed
shapes) present in the compound nucleus decay. The occurrence of the Jacobi
shape transition is also discussed in the framework of a newly developed
rotating liquid drop model.Comment: contribution to the COMEX2 conference proceedings, to be published in
Nucl. Phys.
Evidence for the Jacobi shape transition in hot 46Ti
The gamma-rays from the decay of the GDR in 46Ti compound nucleus formed in
the 18O+28Si reaction at bombarding energy 105 MeV have been measured in an
experiment using a setup consisting of the combined EUROBALL IV, HECTOR and
EUCLIDES arrays. A comparison of the extracted GDR lineshape data with the
predictions of the thermal shape fluctuation model shows evidence for the
Jacobi shape transition in hot 46Ti. In addition to the previously found broad
structure in the GDR lineshape region at 18-27 MeV caused by large
deformations, the presence of a low energy component (around 10 MeV), due to
the Coriolis splitting in prolate well deformed shape, has been identified for
the first time.Comment: 8 pages, 4 figures, proceedings of the COMEX1 conference, June 2003,
Paris; to be published in Nucl. Phys.
COLLECTIVITY IN LIGHT NUCLEI AND THE GDR
The results are presented from the experiments using the EUROBALL and RFD/HECTOR arrays, concerning various aspects of collectivity in light nuclei. A superdeformed band in 42 Ca was found. A comparison of the GDR line shape data with the predictions of the thermal shape uctuation model, based on the most recent rotating liquid drop LSD calculations, shows evidence for a Jacobi shape transition in hot, rapidly rotating 46 Ti and strong Coriolis eects in the GDR strength function. The preferential feeding of the SD band in 42 Ca by the GDR low energy component was observe
Excitation of the dynamical dipole in the charge asymmetric reaction 16O+ 116Sn
Abstract The γ -ray emission from the dynamical dipole formed in heavy-ion collisions during the process leading to fusion was measured for the N/Z asymmetric reaction 16 O + 116 Sn at beam energies of 8.1 and 15.6 MeV/nucleon. High-energy γ -rays and charged particles were measured in coincidence with the heavy recoiling residual nuclei. The data are compared with those from the N/Z symmetric reaction 64 Ni + 68 Zn at bombarding energies of 4.7 and 7.8 MeV/nucleon, leading to the same CN with the same excitation energies as calculated from kinematics. The measured yield of the high-energy γ -rays from the 16 O-induced reaction is found to exceed that of the thermalized CN and the excess yield increases with bombarding energy. The data are in rather good agreement with the predictions for the dynamical dipole emission based on the Boltzmann–Nordheim–Vlasov model. In addition, a comparison with existing data in the same mass region is performed to extract information on the dipole moment dependence