Description
Cluster radioactivity can be understood as a phenomenon between alpha decay and fission, a kind of very asymmetric fission. This radioactivity has been observed for the first time in the 1980s in the decay of 223Ra [1]. Since then cluster emission in more than 20 heavy nuclei has been experimentally evidenced [2]. However, all these cases have daughter nuclei in the close vicinity of doubly-magic 208Pb. With a daughter nucleus in the direct vicinity of a doubly-magic nucleus, the Q value for cluster emission is increased and the cluster decay probability increases compared to alpha decay.
A new region of cluster radioactivity was proposed above doubly-magic 100Sn. The isotopes 112Ba and 114Ba are, according to theoretical predictions, the best candidates to search for cluster radioactivity in this new region of the chart of nuclei by the emission of 12C clusters. However, even in this favourable case, the branching ratio of cluster radioactivity is as small as 10-4 to 10-7 per decay. Therefore, the first step in the search for cluster radioactivity in the 100Sn region is to measure precisely the triple alpha decay energies. For the decay of 114Ba, these alpha energies have already been measured with precisions between 10 and 40 keV. However, more precision is needed to improve the predicting power of models. For 112Ba, no experimental information exists. After the successful measurement of these alpha decay energies, searches for cluster radioactivity can be sought of. During these experiments, the masses of 112Ba and 114Ba will be measured.
[1] H.J. Rose, G.A. Jones, Nature 307 (1984) 245
[2] B. Blank et al., Handbook of Nuclear Physics by I. Tanihata, H. Toki, T. Kajino (Eds.), Springer, 2023