289 research outputs found
Quantum tunneling in ^{277}112 and its alpha-decay chain
The -decay half lives of nuclei in the decay from element
are calculated in a WKB framework using DDM3Y interaction and experimental
Q-values. Theoretical estimation of half lives in the same quantum tunneling
model, using Q-values from the mass formula of
Muntian-Hofmann-Patyk-Sobiczewski, are also presented. Calculated results
furnish corroborating evidence for the experimental findings at RIKEN and GSI.
Certain discrepancies indicate necessity of a better mass formula. Further
experimental data with higher statistics would also be useful.Comment: 10 page
Possibility of synthesizing doubly closed superheavy nucleus
The possibility of synthesizing a doubly magic superheavy nucleus,
, is investigated on the basis of fluctuation-dissipation
dynamics. In order to synthesize this nucleus, we must generate more
neutron-rich compound nuclei because of the neutron emissions from excited
compound nuclei. The compound nucleus has two advantages to
achieving a high survival probability. First, because of small neutron
separation energy and rapid cooling, the shell correction energy recovers
quickly. Secondly, owing to neutron emissions, the neutron number of the
nucleus approaches that of the double closed shell and the nucleus obtains a
large fission barrier. Because of these two effects, the survival probability
of does not decrease until the excitation energy MeV.
These properties lead to a rather high evaporation reside cross section.Comment: 5 pages, 6 figure
Magic nuclei in superheavy valley
An extensive theoretical search for the proton magic number in the superheavy
valley beyond 82 and corresponding neutron magic number after 126 is
carried out. For this we scanned a wide range of elements and their
isotopes. The well established non-relativistic Skryme-Hartree-Fock and
Relativistic Mean Field formalisms with various force parameters are used.
Based on the calculated systematics of pairing gap, two neutron separation
energy and the shell correction energy for these nuclei, we find 120 as the
next proton magic and N=172, 182/184, 208 and 258 the subsequent neutron magic
numbers.Comment: 5 Pages 3 Figures 2 Tables; Phys. Lett. B (2011) (Communicated
The ALTO project at IPN Orsay
In order to probe neutron rich radioactive noble gases produced by
photo-fission, a PARRNe1 experiment (Production d'Atomes Radioactifs Riches en
Neutrons) has been carried out at CERN. The incident electron beam of 50 MeV
was delivered by the LIL machine: LEP Injector Linac. The experiment allowed to
compare under the same conditions two production methods of radioactive noble
gases: fission induced by fast neutrons and photo-fission. The obtained results
show that the use of the electrons is a promising mode to get intense neutron
rich ion beams. Thereafter, the success of this photo-fission experiment, a
conceptual design for the installation at IPN Orsay of a 50 MeV electron
accelerator close to the PARRNe-2 device has been worked out: ALTO Project.
This work has started within a collaboration between IPNO, LAL and CERN groups.Comment: 14 pages, pdf file, International School-Seminar on Heavy-Ion Physics
7 (2002
Skyrme Hartree-Fock Calculations for the Alpha Decay Q Values of Super-Heavy Nuclei
Hartree-Fock calculations with the SKX Skyrme interaction are carried out to
obtain alpha-decay Q values for deformed nuclei above Pb assuming axial
symmetry. The results for even-even nuclei are compared with experiment and
with previous calculations. Predictions are made for alpha-decay Q values and
half-lives of even-even super-heavy nuclei. The results are also compared for
the recently discovered odd-even chain starting at Z=112 and N=165.Comment: 17 pages, 8 figures, 1 tabl
Systematics of Fission Barriers in Superheavy Elements
We investigate the systematics of fission barriers in superheavy elements in
the range Z = 108-120 and N = 166-182. Results from two self-consistent models
for nuclear structure, the relativistic mean-field (RMF) model as well as the
non-relativistic Skyrme-Hartree-Fock approach are compared and discussed. We
restrict ourselves to axially symmetric shapes, which provides an upper bound
on static fission barriers. We benchmark the predictive power of the models
examining the barriers and fission isomers of selected heavy actinide nuclei
for which data are available. For both actinides and superheavy nuclei, the RMF
model systematically predicts lower barriers than most Skyrme interactions. In
particular the fission isomers are predicted too low by the RMF, which casts
some doubt on recent predictions about superdeformed ground states of some
superheavy nuclei. For the superheavy nuclei under investigation, fission
barriers drop to small values around Z = 110, N = 180 and increase again for
heavier systems. For most of the forces, there is no fission isomer for
superheavy nuclei, as superdeformed states are in most cases found to be
unstable with respect to octupole distortions.Comment: 17 pages REVTEX, 12 embedded eps figures. corrected abstrac
alpha-decay chains of Z=114, A=289 and Z=118, A=293 in the relativistic mean-field model
A comparison of calculated and experimental Q_alpha values of superheavy
even-even nuclei and a few selected odd-N nuclei is presented in the framework
of the relativistic mean-field model with the parameterization NL-Z2. Blocking
effects are found to be important for a proper description of Q_alpha of odd
mass nuclei. The model gives a good overall description of the available
experimental data. The mass and charge assignment of the recently measured
decay chains from Dubna and Berkeley is in agreement with the predictions of
the model. The analysis of the new data does not allow a final conclusion about
the location of the expected island of spherical doubly-magic superheavy
nuclei.Comment: 4 pages REVTeX, 4 eps figures, accepted for publication in Phys. Rev.
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