The new isotope

The isotopes 237, 238, 240Cf were produced in irradiations of 204, 206, 207Pb targets with 36S ions. At bombarding energies close to the Coulomb barrier two or three neutrons were evaporated from the compound nuclei 240, 242, 243Cf . Cross-sections were on the order of a few hundred nanobarns. For the isotope 240Cf a spontaneous fission branching of 0.015±0.002 was determined. The new isotope 236Cm was produced by $ \alpha$ decay of 240Cf and identified by $ \alpha$ -$ \alpha$ correlations. It decays with an $ \alpha$ -decay energy of (6954± 20)keV and a half-life of (410±50 s. For the first time, the $ \alpha$ decay of 237Cf was observed having an energy of (8081±20 keV. For the isotope 233Cm a half-life of ( 23+13 -6 s was measured for first time. Spontaneous fission of 237, 238Cf was confirmed and mass-excess values of the nuclei 236Cm and 237, 240Cf were determined