Measurement of cold fission for 229Th(nth, f), 232U(nth, f) and 239Pu(nth, f) with the Cosi fan tutte spectrometer

Abstract The light-fragment-group mass-energy correlations for 229 Th(n th , f), 232 U(n th , f) and 239 Pu (n th , f) measured with the Cosi fan tutte, have been used to determine the cold fission probability for these fissioning systems. These are the first results on cold fission for 229 Th(n th , f) and 232 U(n th , f). For 229 Th(n th , f) cold fission is realised for the whole mass range M L ≈ 80–99 present in the mass spectrum, but the coldest fission shows up for M L ≈ 85. For 232 U(n th , f) cold fission is present for M L ≈ 84–107, with the coldest fission manifesting for M L ≈ 100–105. In the case of 239 Pu(n th , f), cold fission exists for M L ≈ 95–112 and here the coldest fission is produced for M L ≈105–110. This systematic study shows that the shells in the nascent fragments seem to play a decisive role in the realisation of cold fission. These results are discussed in terms of the existing concepts and ideas on this phenomenon.