Q-value dependence of inelastic scattering and multinucleon transfer reactionsAl27+

Takeshi Mikumo

¹

,

M. Sasagase

²

,

Masataka Satô

³

et al.

Abstract

Despite the low bombarding energy, the general features of (i) energy spectra, (ii) the optimum Q values Q,~, and (iii) angular distributions in 5 MeV intervals in Q are very similar to those of much higher energy data of heavier systems: i.e. , (i) dominance of deep inelastic reactions, (ii) Q,ff values well reproduced by the "universal" relations previously found for deep inelastic reactions, and (iii) cr(8,Q) of a form A expf -p,(Q)8]/sin8. The variations of Q, "with 8, and of p, with Q and n, the number of transferred nucleons, are discussed in connection with the gradual evolution in reaction mechanisms from quasielastic to deep inelastic to complete fusion.

Complex-fragment emission in low-energy light-ion reactions

“…5 for comparison. It is seen that, in all reactions, the time scale decreases as the fragment charge increases, which is in conformity with a previous study by Mikumo et al [54]. This is expected because the heavier fragments (nearer to the projectile) require less nucleon exchange and therefore less time; on the other hand, the Si reactions, which is actually the case (Fig.…”

Dissipative collisions in16O+27Alat<

“…al. [8] for the same reaction at 88 MeV, the time scales decrease as the fragment charges increase. This is expected because the heavier fragments ( nearer to the projectile ) require less number of nuleon transfer and therefore less time; on the other hand the emission of lighter fragments requires exchange of more number of nucleons and therefore longer times.…”

“…Several studies made earlier for 16 O + 27 Al system at incident energies in the range of ∼60 -100 MeV have indicated that fragments emitted in the reaction are mainly originating from cluster transfer [16], projectile sequential breakup [2] and multi-nucleon transfer [7][8][9] processes. The role of direct two-body and three-body projectile breakup in fragment emission from 16 O + 27 Al reaction in the energy range of ∼70 -125 MeV have also been investigated recently [3].…”

“…The origin of these fragments extends from quasi-elastic (QE)/projectile-breakup [2,3], deep inelastic (DI) transfer and orbiting [4][5][6][7][8][9][10], to fusion-fission (FF) [1,[10][11][12][13][14][15] processes and in some cases the structure of the nuclei has been found to play an important role. The distinction between different reaction mechanisms, in general, and the DI and FF processes, in particular, is very difficult for light system (A cn ≤ 40) [1,10] as in these cases there is strong overlap in the elemental distributions of the fragment emitted in the two processes.…”

“…Such lifetimes are incompatible with the formation of an equilibrated compound nucleus, but may still reflect significant energy damping within a deep-inelastic mechanism. From the measured forward peaked angular distribution it is possible to estimate the life time of the intermediate di-nuclear complex using a diffractive Regge-pole model [8,20]. The angular distributions are fitted with the following expression dσ/dΩ = (C/sinθ c.m.…”