Savi Goyal

Effect of fissility in fission time scales for 16,18O+194,198Pt systems

The pre-scission neutron multiplicities have been studied for 16,18O+194,198Pt at 50, 61, 71.7, 79 MeV excitation energy populating 210,212,214,216Rn compound nuclei having fissility 0.735, 0.732, 0.729, 0.726 respectively. Fission Time scales were extracted from the measured pre-scission neutron multiplicity and statistical model PACE2. The effect of fissility on fission time scales has been measured. It is found that fission time scales increases in a consistent way with fissility of the compound nuclei (CN) populated. The fission delays extracted for different CN are in good agreement with earlier published data for heavier systems [1, 2]. In the present work it is shown systematically that the fission time scales generally increases with fissility value of CN.

Fusion and transfer reactions around the Coulomb barrier for 28Si+90,94Zr systems

Fusion excitation functions and transfer probabilities were measured for 28Si+90,94Zr systems around the Coulomb barrier, using the recoil mass separator, Heavy Ion Reaction Analyzer (HIRA) at Inter University Accelerator Centre (IUAC), New Delhi. The aim of these experiments was the study of coupling effects of inelastic and transfer channels on the sub-barrier fusion cross section enhancement. The experimental fusion cross sections were found to be strongly enhanced as compared to one dimensional barrier penetration model (1-d BPM) predictions in both the cases. The trend of data could be easily reproduced theoretically using coupled channels code CCFULL in the case of 28Si+90Zr but the observed enhancement could not be explained in the case of 28Si+94Zr, which may be attributed to the coupling of multinucleon transfer channels as both isotopes have similar collective strengths. The transfer probabilities in the case of 94Zr were found to be substantially higher than for 90Zr in the sub-barrier region.

Dipole bands in high spin states of 57135La78

High spin states of 135La have been investigated using the reaction 128Te(11B,4n)135La at a beam energy of 50.5 MeV. Two negative parity dipole bands (ΔI = 1) have been established. Crossover E2 transitions have been observed for the first time in one of the dipole bands. For the Tilted Axis Cranking (TAC) calculations, a three-quasiparticle (3qp) configuration π(h11/2)1⊗ν(h11/2)−2 and a five-quasiparticle (5qp) configuration π(h11/2)1(g7/2/d5/2)2⊗ν(h11/2)−2 have been taken for the two negative parity dipole bands. The comparison of experimental observables with TAC calculations supports the configuration assignments for both the dipole bands.