Showing papers by "V. V. Parkar published in 2009"
TL;DR: In this article, the authors showed that the complete fusion excitation function at near barrier energies can be suppressed by 32% in the case of the Coulomb barrier penetration model with strongly bound projectiles forming a similar compound nucleus.
Abstract: Complete fusion excitation function for the $^{6}\mathrm{Li}+^{144}\mathrm{Sm}$ reaction has been measured at near barrier energies by the activation technique Coupled-channel calculations show an enhancement in fusion cross section at energies below the barrier compared to the one-dimensional barrier penetration model calculation, but they overpredict it in the entire energy range compared to the experimental data Reduced fusion cross sections for the present system at energies normalized to the Coulomb barrier were also found to be systematically lower than those with strongly bound projectiles forming a similar compound nucleus These two observations conclusively show that the complete fusion cross section, at above barrier energies, is suppressed by $~32%$ in the $^{6}\mathrm{Li}+^{144}\mathrm{Sm}$ reaction Reanalyses of existing fusion data for $^{7}\mathrm{Li}+^{165}\mathrm{Ho}$ and $^{7}\mathrm{Li}+^{159}\mathrm{Tb}$ also show a suppression compared to those with strongly bound projectiles, which contradicts earlier conclusions The fusion suppression factor seems to exhibit a systematic behavior with respect to the breakup threshold of the projectile and the atomic number of the target nucleus
57 citations
TL;DR: The present results for a system with weakly bound projectile confront the current understanding of the fusion hindrance at these low energies, underlying the role of internal reorganization on the dynamical path towards fusion.
Abstract: Results of measurement of residues formed in fusion of $^{6}\mathrm{Li}$ with $^{198}\mathrm{Pt}$ in the energy range of $0.68lE/{V}_{b}l1.3$ using a new sensitive off-beam technique are reported. The fusion excitation function and the derived average angular momenta do not indicate a change of slope at deep sub-barrier energies, contrary to recent observations. The present results for a system with weakly bound projectile confront the current understanding of the fusion hindrance at these low energies, underlying the role of internal reorganization on the dynamical path towards fusion.
44 citations
TL;DR: In this article, the exclusive projectile breakup cross section in the Li 6 + Bi 209 reaction has been measured at E lab = 40 and 36 MeV, respectively, and the average sequential breakup data corresponding to the resonant state are in good agreement with continuum discretized coupled channels (CDCC) calculations.
34 citations
11 Jan 2009-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: In this article, an activation technique using coincidences between characteristic X-rays and γ-rays to obtain absolute cross-sections is described, particularly useful in the case of nuclei that decay by electron capture.
Abstract: An activation technique using coincidences between characteristic X-rays and γ -rays to obtain absolute cross-sections is described. This method is particularly useful in the case of nuclei that decay by electron capture. In addition to the reduction of possible contamination, an improved detection sensitivity is achieved as compared to inclusive measurements, thereby allowing the extraction of absolute fusion cross-sections in the nano-barn range. Results of this technique for Li 6 + Pt 198 system, at energies around the Coulomb barrier are described. Future applications with low intensity radioactive ion beams are also discussed.
12 citations
TL;DR: In this paper, the elastic scattering and the 6 He angular distributions were measured in 7 Li + 7 Li reaction at two energies, E lab = 20 and 25 MeV, and FRDWBA calculations have been performed to explain the measured 6 He data.
Abstract: The elastic scattering and the 6 He angular distributions were measured in 7 Li + 7 Li reaction at two energies, E lab = 20 and 25 MeV. FRDWBA calculations have been performed to explain the measured 6 He data. The calculations were very sensitive to the choice of the optical model potentials in entrance and exit channels. The one-step proton transfer was found to be the dominant reaction mechanism in 6 He production.
1 citations