Cold compact and cold deformed spontaneous fission of /sup 252/Cf

Structures with a period of 5 amu are observed in the mass distributions of fragments and in the number of prompt neutrons as a function of the fragment mass in the spontaneous fission of /sup 252/Cf. The structures appear both for minimal fragment excitation energies (cold, compact fission) and for maximum excitation energies (cold deformed fission).