Cluster radioactivity is a nuclear decay process in which a light nucleus, but heavier than 4-He is emitted from a heavy nucleus. It was observed experimentally in the 1980s in several actinide nuclei as an exotic decay process accompanying alpha radioactivity. Isotopes from 14-C to 34-Si were observed as an emitted cluster. The driving effect leading to this type of decay is the strong shell effect in a heavy mass residue: doubly magic 208-Pb. Cluster radioactivity may be described as super-asymmetric fission with a separate fission valley on the potential energy surface. Calculations show that in the region of super-heavy nuclei with Z>110 the analog process, with 208-Pb as one fragment, may be the dominant decay channel. This indicates on a new type of super-asymmetric fission may be observed, besides already observed asymmetric and symmetric fission.
Adam Maj