Towards saturation of the electron-capture delayed fission probability: The new isotopes 240 Es and 236 Bk

Alpha Decay and Beta-Delayed Fission: Tools for Nuclear Physics Studies

“…To conclude this section, we mention that recently, βDF of 236 Bk and 240 Es was identified at the gas-filled separator RITU at JYFL [137], while βDF of 230 Am was observed at the GARIS gas-filled separator at RIKEN [138,139]. For 236 Bk and 240 Es, quite large βDF probabilities, of the order of ∼10% were derived, while a lower limit of P βDF >30% was derived for 230 Am.…”

β -delayed fission of Am230

“…of two recently reported values for 240 Es and 236 Bk from [2]. Figure 1 shows an overall linear dependence of log(P βDF ) on the Q EC (parent) − B f (daughter) difference.…”

“…The observed half-life behavior of fission events in βDF is determined by the half-life of the feeding β-decaying parent nucleus. Up to now, 28 βDF nuclides are known, all of them being odd-odd; see the references in the recent review [1] and the study of 240 Es and 236 Bk in [2]. An important experimental quantity is the βDF probability, which is defined as the ratio of the number of βDF decays, N βDF , to the number of β decays, N β , of the parent nuclide:…”

2017 update of the discoveries of nuclides

“…240 Es and 236 Bk were first reported in the paper "Towards saturation of the electron-capture delayed fission probability: The new isotopes 240 Es and 236 Bk" by Konki et al 12 A 34 S beam was accelerated to 174 and 178 MeV with the K-130 cyclotron of the Accelerator Laboratory of the Department of Physics, University of Jyväskylä, Finland and bombarded 209 BiO 2 foils. Evaporation residues were separated with the gas-filled recoil separator RITU and identified with the GREAT focal plane spectrometer.…”