The system of intermediate fissility ${}^{132}\mathrm{Ce}$ has been studied experimentally and theoretically to investigate the dissipation properties of nuclear matter. Cross sections of fusion-fission and evaporation-residue channels together with light charged particle multiplicities in both channels, their spectra, light charged particle-evaporation residue angular correlations, and mass-energy distribution of fission fragments have been measured. Theoretical analysis has been performed using a multidimensional stochastic approach coupled with a Hauser-Feshbach treatment of particle evaporation. The main conclusions are that the full one-body shape-dependent dissipation mechanism allows the reproduction of the full set of experimental data and that after a time ${\tau }_d=5\times {10}^{-21}$ s from the equilibrium configuration of the compound nucleus, fission decay can occur in a time that can span several orders of magnitude.

International audienceThe new neutron-deficient nuclei 240 Es and 236 Bk were synthesised at the gas-filled recoil separator RITU. They were identified by their radioactive decay chains starting from 240 Es produced in the fusion–evaporation reaction 209 Bi( 34 S,3n) 240 Es. Half-lives of 6(2)s and 22−6+13s were obtained for 240 Es and 236 Bk, respectively. Two groups of α particles with energies Eα=8.19(3)MeV and 8.09(3)MeV were unambiguously assigned to 240 Es. Electron-capture delayed fission branches with probabilities of 0.16(6) and 0.04(2) were measured for 240 Es and 236 Bk, respectively. These new data show a continuation of the exponential increase of ECDF probabilities in more neutron-deficient isotopes

The NEutron Detector Array (NEDA) project aims at the construction of a new high-efficiency compact neutron detector array to be coupled with large [equation]-ray arrays such as AGATA. The...

The electron-capture decay followed by a prompt fission process was searched for in the hitherto unknown most neutron-deficient Md isotope with mass number 244. Alpha decay with $\alpha$-particle energies of 8.73–8.86 MeV and with a half-life of ${0.30}_{-0.09}^{+0.19}\mathrm{s}$ was assigned to ${}^{244}\mathrm{Md}$. No fission event with a similar half-life potentially originating from spontaneous fissioning of the short-lived electron-capture decay daughter ${}^{244}\mathrm{Fm}$ was observed, which results in an upper limit of 0.14 for the electron-capture branching of ${}^{244}\mathrm{Md}$. Two groups of fission events with half-lives of ${0.9}_{-0.3}^{+0.6}\mathrm{ms}$ and $5_{-2}^{+3}\mathrm{ms}$ were observed. The ${0.9}_{-0.3}^{+0.6}\mathrm{ms}$ activity was assigned to originate from the decay of ${}^{245}\mathrm{Md}$. The origin of eight fission events resulting in a half-life of $5_{-2}^{+3}\mathrm{ms}$ could not be unambiguously identified within the present data while the possible explanation has to invoke previously unseen physics cases.