D. Gupta

Characterization of fragment emission inNe20(7–10 MeV/nucleon)+C12reactions

The inclusive energy distributions of the complex fragments (3{<=}Z{<=}7) emitted from the bombardment of {sup 12}C by {sup 20}Ne beams with incident energies between 145 and 200 MeV have been measured in the angular range 10 deg.{<=}{theta}{sub lab}{<=}50 deg. Damped fragment yields in all the cases have been found to have the characteristic of emission from fully energy equilibrated composites. The binary fragment yields are compared with the standard statistical model predictions. Whereas Li and Be fragments yields are in agreement with statistical-model calculations, enhanced yields of entrance channel fragments (5{<=}Z{<=}7) indicate the survival of orbiting-like process in {sup 20}Ne+{sup 12}C system at these energies.

Study of dissipative collisions of 20Ne (≈7-11 MeV/nucleon) + 27Al

The inclusive energy distributions of complex fragments (3 ≤ 9) emitted in the reactions 20 Ne (145, 158, 200, 218 MeV) + 27 Al have been measured in the angular range 10°-50°. The fusion-fission and the deep-inelastic components of the fragment yield have been extracted using multiple Gaussian functions from the experimental fragment energy spectra. The elemental yields of the fusion-fission component have been found to be fairly well explained in the framework of the standard statistical model. It is found that strong competition occurs between the fusion-fission and the deep-inelastic processes at these energies. The time scale of the deep-inelastic process was estimated to be typically in the range of ∼10 -21 -10 -22 s, and it was found to decrease with increasing fragment mass. The angular momentum dissipations in the fully energy damped deep-inelastic process have been estimated from the average energies of the deep-inelastic components of the fragment energy spectra. The estimated angular momentum dissipations, for lighter fragments in particular, are found to be greater than those predicted by the empirical sticking limit.

Survival of orbiting in Ne 20 (7–10 MeV/nucleon) + C 12 reactions

The inclusive energy distributions of fragments with Z 3 emitted from the bombardment of 12 Cb y 20 Ne beams with incident energies between 145 and 200 MeV have been measured in the angular range θlab ∼ 10 ◦ –50 ◦ . Damped fragment yields in all cases have been found to be characteristic of emission from fully energy equilibrated composites; for B and C fragments, average Q values, � Q� , were independent of the center-of-mass emission angle (θc.m.), and the angular distributions followed a ∼1/sinθc.m.-like variation, signifying long lifetimes of the emitting dinuclear systems. Estimates of total yields of these fragments have been found to be much larger than those predicted by the standard statistical model. This may be indicative of the survival of an orbiting-like process in the 12 C + 20 Ne system at these energies.

Fragment emission studies of the {sup 16}O+{sup 12}C reaction

The inclusive energy distributions of the fragments (3{ values for the fragments B, Be, and Li are found to be independent of the center of mass emission angles, which further suggest that at all angles, the fragments are emitted from completely equilibrated source at all incident energies considered here. The yields of the fragments Li and Be are in agreement with statistical-model predictions. The enhanced yields of entrance channel fragment B indicate the survival of orbiting-like process in {sup 16}O+{sup 12}C system at these energies.

Study of dissipative collisions of {sup 20}Ne (MeV/{approx_equal}7-11 nucleon)+ {sup 27}Al

The inclusive energy distributions of complex fragments (3{<=}9) emitted in the reactions {sup 20}Ne (145, 158, 200, 218 MeV) + {sup 27}Al have been measured in the angular range 10 deg. - 50 deg. The fusion-fission and the deep-inelastic components of the fragment yield have been extracted using multiple Gaussian functions from the experimental fragment energy spectra. The elemental yields of the fusion-fission component have been found to be fairly well explained in the framework of the standard statistical model. It is found that strong competition occurs between the fusion-fission and the deep-inelastic processes at these energies. The time scale of the deep-inelastic process was estimated to be typically in the range of {approx}10{sup -21}-10{sup -22} s, and it was found to decrease with increasing fragment mass. The angular momentum dissipations in the fully energy damped deep-inelastic process have been estimated from the average energies of the deep-inelastic components of the fragment energy spectra. The estimated angular momentum dissipations, for lighter fragments in particular, are found to be greater than those predicted by the empirical sticking limit.

Survival of orbiting inNe20(7–10 MeV/nucleon) +C12reactions

The inclusive energy distributions of fragments with Z 3 emitted from the bombardment of 12 Cb y 20 Ne beams with incident energies between 145 and 200 MeV have been measured in the angular range θlab ∼ 10 ◦ –50 ◦ . Damped fragment yields in all cases have been found to be characteristic of emission from fully energy equilibrated composites; for B and C fragments, average Q values, � Q� , were independent of the center-of-mass emission angle (θc.m.), and the angular distributions followed a ∼1/sinθc.m.-like variation, signifying long lifetimes of the emitting dinuclear systems. Estimates of total yields of these fragments have been found to be much larger than those predicted by the standard statistical model. This may be indicative of the survival of an orbiting-like process in the 12 C + 20 Ne system at these energies.

Survival of orbiting in {sup 20}Ne (7-10 MeV/nucleon) + {sup 12}C reactions

The inclusive energy distributions of fragments with Z 3 emitted from the bombardment of 12 Cb y 20 Ne beams with incident energies between 145 and 200 MeV have been measured in the angular range θlab ∼ 10 ◦ –50 ◦ . Damped fragment yields in all cases have been found to be characteristic of emission from fully energy equilibrated composites; for B and C fragments, average Q values, � Q� , were independent of the center-of-mass emission angle (θc.m.), and the angular distributions followed a ∼1/sinθc.m.-like variation, signifying long lifetimes of the emitting dinuclear systems. Estimates of total yields of these fragments have been found to be much larger than those predicted by the standard statistical model. This may be indicative of the survival of an orbiting-like process in the 12 C + 20 Ne system at these energies.