Subinit Roy

Fusion ofLi6withTb159at near-barrier energies

Complete and incomplete fusion cross sections for {sup 6}Li + {sup 159}Tb have been measured at energies around the Coulomb barrier by the {gamma}-ray method. The measurements show that the complete fusion cross sections at above-barrier energies are suppressed by {approx}34% compared to coupled-channel calculations. A comparison of the complete fusion cross sections at above-barrier energies with the existing data for {sup 11,10}B + {sup 159}Tb and {sup 7}Li + {sup 159}Tb shows that the extent of suppression is correlated with the {alpha} separation energies of the projectiles. It has been argued that the Dy isotopes produced in the reaction {sup 6}Li + {sup 159}Tb at below-barrier energies are primarily due to the d transfer to unbound states of {sup 159}Tb, while both transfer and incomplete fusion processes contribute at above-barrier energies.

Influence of projectile α-breakup threshold on complete fusion

Abstract Complete fusion excitation functions for B 11 , 10 + Tb 159 have been measured at energies around the respective Coulomb barriers, and the existing complete fusion measurements for Li 7 + Tb 159 have been extended to higher energies. The measurements show significant reduction of complete fusion cross sections at above-barrier energies for both the reactions, B 10 + Tb 159 and Li 7 + Tb 159 , when compared to those for B 11 + Tb 159 . The comparison shows that the extent of suppression of complete fusion cross sections is correlated with the α-separation energies of the projectiles. Also, the two reactions, B 10 + Tb 159 and Li 7 + Tb 159 were found to produce incomplete fusion products at energies near the respective Coulomb barriers, with the α-particle emitting channel being the favoured incomplete fusion process in both the cases.

Sub- and above-barrier fusion of loosely bound 6Li with 28Si

Fusion excitation functions are measured for the system 6Li + 28Si using the characteristic

Wide-angle measurement of 48 MeV 6Li projectile fragmentation on 197Au

\gamma

Small quadrupole deformation for the dipole bands in 112 In

-ray method, encompassing both the sub-barrier and above-barrier regions, viz, Elab = 7-24 MeV. Two separate experiments were performed, one for the above-barrier region ( Elab = 11-24 MeV) and another for the below-barrier region ( Elab = 7-10 MeV). The results were compared with our previously measured fusion cross-section for the 7Li + 28Si system. We observed the enhancement of the fusion cross-section at sub-barrier regions for both 6Li and 7Li , but the yield was substantially larger for 6Li . However, for well-above-barrier regions, a similar type of suppression was identified for both the systems.

Spectroscopic factors for alpha decay in the N(p)N(n) scheme

Abstract The 6 Li → α + d projectile breakup at E ( 6 Li) = 48 MeV with a 197 Au target is studied at large relative fragment energies. Both inclusive and exclusive measurements are carried out. The peaks corresponding to the protons and α-particles appear near the expected beam velocity positions while the deuterons and tritons are shifted to lower energy values. Calculations in the framework of both prior- and post-form distorted-wave Born approximation theories delineate an oscillatory structure for the exclusive cross section at larger α - d separation angles in consonance with the data profile. The oscillation is found to be a result of delicate Coulomb and nuclear interference. The distorted-wave analysis of the existing data at E ( 6 Li) = 75 MeV, where the Coulomb effect is smaller, show a different feature altogether having no oscillation at larger angles. At larger angles, the factorisation theory for uncorrelated events seems to hold better at 75 MeV incident energy than at 48 MeV. The implications of these results are discussed.

Analysing power puzzle of p+6Li scattering: consistent analysis with density and momentum dependent finite range effective interaction

High spin states in 112 In were investigated using the 100 Mo( 16 O ,p 3n) reaction at 80 MeV. The excited level has been observed up to 5.6 MeV excitation energy and spin ∼20¯ h with the level scheme showing three dipole bands. Polarization and lifetime measurements were carried out for the dipole bands. Tilted axis cranking model calculations were performed for different quasiparticle configurations of this doubly odd nucleus. Comparison of the calculations of the model with the B(M1) transition strengths of the positive- and negative-parity bands firmly established their configurations.

Helium nuclei around the neutron drip line

Abstract Lifetime values for alpha decay in even–even nuclei with Z = 84 – 98 and N = 128 – 152 have been calculated in the superasymmetric fission model. The interaction between the alpha particle and the daughter nucleus has been formed in the double folding approach using a density dependent NN interaction. The densities have been obtained using the Relativistic Mean Field formalism. The spectroscopic factors for the decays have been deduced and are shown to vary smoothly as a function of effective numbers of valence nucleons, N p and N n chosen with a suitable core. The implication of such a smooth behaviour has been discussed.

Importance of the1n-stripping process in the6Li + 159Tb reaction

Abstract The p+ 6 Li angular distribution data at E p = 10–136 MeV for both the ground state (1 + ) and the first excited state (3 1 + ) of 6 Li are analysed with a density and momentum dependent finite range effective interaction (SBM) in a single folding model. For the polarised incident protons at E p = 10, 49.75, 65 and 80 MeV, the analyses of the analysing power data are also carried out. For comparison, analyses with the density independent M3Y interaction and pure phenomenological potential are presented. The transition densities are computed from the 6 Li(e,e′) data in the Fourier-Bessel series expansion method. The SBM potential along with these experimental density profiles of 6 Li gives a reasonable description of both the cross section and the analysing power data. In a coupled channel calculation, the effect of coupling the ground state to the 3 1 + resonant state of 6 Li is found to be important at E p = 10 and 24 MeV. The effect of this coupling becomes less significant at higher incident energies where the simple one step distorted wave Born approximation calculations fit the measured cross section data. The puzzling discrepancy observed in the previous analyses of the analysing power data is greatly reduced by the use of the SBM interaction.

Nondestructive Characterization of Municipal-Solid-Waste-Contaminated Surface Soil by Energy-Dispersive X-ray Fluorescence and Low-Z (Atomic Number) Particle Electron Probe X-ray Microanalysis

Neutron rich He nuclei have been investigated using relativistic mean field approach in co-ordinate space. Elastic partial scattering cross sections for proton scattering in inverse kinematics have been calculated using the theoretically obtained density for