Fragment configurations in multi-cluster fission

Besides fission into two or three fragments, a heavy or superheavy nucleus spontaneously breaks into four, five or six nuclei, of which two are asymmetric or symmetric heavy fragments and the others are light clusters. Examples an presented for the cold fission of Cf-252, in which the emitted clusters are: 2 alpha, alpha + Be-10, 3 alpha, alpha + He-6 + Be-10 and 4 alpha. A comparison is made with the recently observed Cf-252 cold binary fission and cold ternary (accompanied by an a particle or by Be-10 cluster) fission. The strong shell effect associated with the doubly magic heavy fragment Sn-132 is emphasized. From the analysis of different configurations of fragments we conclude that the most favourable mechanism in such a decay mode should be cluster emission from an elongated neck formed between the two heavy fragments.