Abstract
The target-like C-yield in the decay of compound systems 32 S ∗ and 31 P ∗ formed in 20 Ne+ 12 C and 19 F+ 12 C reactions at E ∗ CN=60 MeV, is studied for the contribution of fusion-fission (ff) decay cross section σ ff and the deep inelastic (DI) orbiting σorb from the compound nucleus (CN) and non-compound nucleus nCN processes, respectively. The calculations are performed using the collective clusterization of fragments within the dynamical cluster-decay model (DCM) of Gupta and collaborators. Besides studying the compe- tition between ff and DI orbiting phenomenon in the C-yield of these systems, we exclusively investigate the preformation and barrier penetration probabilities P0 and P as a function of angular momentumvalues which subsequently affects the contributions of σ ff and σorb. For calculating the contribution of σ ff in the C-yield, we have added the contributions from all the minimized intermediate mass fragments (IMFs) for Z= 6i n the calculated fragmentation potentials for 32 S ∗ (IMFs 11,12,13 C are minimized) and for 31 P ∗ (IMFs 12,13 C are min- imized), while calculating subsequently, P0 and the P for these IMFs. The distribution of preformed clusters/ fragments as a function of fragment mass visibly explore the nuclear structure effects for the C-yield in decay of these compound systems, wherein, it is shown to be more favoured in the decay of 31 P ∗ in comparison to 32 S ∗ decay. The contribution of σorb to the C-yield is calculated from P at different allowed � -values (uptomax and also P≤1) of the outgoing fragments (same as that in the entrance channel, i.e., P0=1). Though preliminary but useful results indicates the competition between the CN and nCN process in the C-yield for the compound system 32 S ∗ only while the decay of 31 P ∗ is of pure CN origin, as observed in the experimental study. The calculations are in good comparison with the available experimental data.
Highlights
Heavy-ion reactions present novel and interesting features to understand the dynamics of very light mass nuclear systems (A ∼20-30)
The processes of fusion-fission and a deep inelastic (DI) orbiting mechanism are in competition for these systems [1, 2]
A completely equilibrated compound nucleus (CN) is formed, which decays into various exit channels, independent of entrance channel but depending on their masses [3,4,5], whereas in a deep inelastic (DI) orbiting mechanism a long lived dinuclear molecular system is formed with strong memory of entrance channel which subsequently decays into targetprojectile like fragments and contribute σorb to the overall decay cross section
Summary
Heavy-ion reactions present novel and interesting features to understand the dynamics of very light mass nuclear systems (A ∼20-30). In the present study we will investigate the decay of 32S∗ and 31P∗ into the intermediate mass fragments (IMFs) having Z=6, i.e., C-yield only. Instructively, both the compound systems are excited at the excitation energy EC∗ N=60 MeV, in order to compare their decays. We look for the effects of angular momentum alongwith nuclear structure effects in the decay of 32S∗ and 31P∗ into the IMFs having Z=6 These compound systems are negative Qout-value systems that means they would decay only if they are produced in heavy ion reactions with compound nucleus excitation energy sufficiently enough so that. The same equation (3) is used for σnCN or σorb, calculated as the DI orbiting (orb) process, since incoming nuclei keep their identity, and P0=1, and P is calculated for incoming channel
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