Description
The formation of superheavy elements (atomic number Z $\geq$ 104) presents a valuable opportunity to expand our understanding of fundamental quantum and nuclear physics. At accelerator facilities, superheavy elements are synthesised by colliding two heavy ions with sufficient energy to overcome their mutual Coulomb repulsion. These nuclei may then undergo fusion (equilibrating in mass, energy, and charge) to form a compound nucleus that de-excites via fission, or, extremely rarely, by evaporating neutrons to form a superheavy element. The formation of a compound nucleus faces extreme competition from quasifission, where the system reseparates before it is able to fully equilibrate. Quasifission suppresses the probability of compound formation, $P_\mathrm{CN}$, by orders of magnitude.
To maximise our chance of discovering new superheavy elements beyond oganesson (Z = 118), we need to determine new formation reactions that maximise $P_\mathrm{CN}$. However, large variation between theoretical models means that we must rely on measuring $P_\mathrm{CN}$ experimentally, requiring us to disentangle the strongly overlapping quasifission and fusion-fission outcomes.
In this talk, I will present the results of a measurement of $^{54}$Cr + $^{208}$Pb, forming the superheavy $^{262}$Sg, performed at the Heavy Ion Accelerator Facility at the Australian National University. We have developed a novel technique to extract $P_\mathrm{CN}$ by simultaneously fitting the two-dimensional mass-energy distributions of quasifission and fusion-fission fragments. This method is more sensitive than existing techniques, allowing us to determine $P_\mathrm{CN}$ with a higher degree of precision than previous work. This becomes increasingly important when we move towards synthesis reactions for new superheavy elements, where fusion becomes even less likely.
| I am the presenting author | Yes |
|---|