Research Projects

Recent years, much attention has been made to investigate the dynamics of the multiplicity of processes like complete fusion (CF)/compound nucleus (CN), incomplete fusion (ICF)/breakup fusion (BUF), pre-compound (PCN) emission in heavy ion (HI) reactions at projectile energies below 10 MeV per nucleon [1]. In this energy regime, the aforesaid processes are found to be completing each other. As such, it becomes difficult to obtain individual contribution CF, ICF and PCN emission in these reaction processes. When an excited compound nucleus is formed in a nuclear interaction, it decays via different de-excitation process to release its energy either by particle emission or gamma-rays. Such decay process is quite complicated as the time involved is rather short 10-16 to 10-22 second. During this time duration, the aforesaid reaction dynamics are governed by the excitation energy and angular momenta of the compound system. Experimentally, excitation energy of compound nucleus is precisely obtained with the help of the energy supplied from accelerator, mass numbers of compound nucleus and its reactions Q-value. However, it is quite difficult to obtain the precise value of the angular momenta in HI reactions which depend mainly on interaction trajectory of fused nuclei. At energies above the Coulomb barrier but below 10 MeV/nucleon, where the angular momenta of the system lying less than its critical values, the most dominating process is complete fusion (CF) process, incomplete fusion and pre-compound (PCN) emission. The presence of PCN-particles in reaction below 10 MeV per nucleon energy decreases the probability of CN or CF process. Consequently, there is a reduction of CF cross-section. In addition to above, if somehow an excited compound nucleus is formed at the value of angular momenta becomes larger than the critical values required for complete fusion process. In this case the system, it releases the excess momenta by breaking the projectile into its fragments. Breaking of projectile into the fragments before fusion takes place termed as incomplete fusion (ICF) or breakup fusion (BUF) process. As such, at higher values angular momenta, the ICF process dominates over CF process and reduces the probability of CF process in a similar manner as in case of PCN emission. In light of the above, both ICF and PCN emission reduce substantially CF cross-section and hence, the path of formation of super heavy element (SHE) may also be hindered. In order to form a nucleus in the SHE region, it is important to determine the contribution of CF, ICF and PCN emission in a reaction [2]. This is the primarily goal of the present investigation. References: 1. F. Amorini, M. Cabibbo, G. Cardelaa, et al, Phys. Rev. C 58, 987 (1998), 2. H. Wang, H. Otsu, N. Chiga, S. Kawase, S. Takeuchi et al, Nature (Communication Physics) Article no 72, (2019) https://doi.org/10.1038/s42005-019-0165-1 .