Ternary fission

However, in this conventional fission of large nuclei, the binary process happens merely because it is the most energetically probable.

Although particles as large as argon nuclei may be produced as the smaller (third) charged product in the usual ternary fission, the most common small fragments from ternary fission are helium-4 nuclei, which make up about 90% of the small fragment products.

The second-most common particles produced in ternary fission are Tritons (the nuclei of tritium), which make up 7% of the total small fragments, and the third-most are helium-6 nuclei (which decay in about 0.8 seconds to lithium-6).

[2] This phenomenon was initially detected in 1957, within the environs of the Savannah River National Laboratory.

It produces three nearly equal-sized charged fragments (Z ~ 30) but only happens in about 1 in 100 million fission events.

True ternary fission has so far only been observed in nuclei bombarded by heavy, high energy ions.