New nuclides228,229Pu

In continuation of our work on investigation of the neutron-deficient plutonium isotopes [1] we carried out the experiments aimed to produce new isotopes^228,229Pu. The isotope²²⁸Pu has been produced in the bombardment of the²⁰⁸Pb target with a beam of²⁴Mg and the isotope²²⁹Pu — in the reactions of^207,208Pb targets with²⁶Mg projectiles. The isotopes were identified after in-flight separation from the beam and target-like particles by the VASSILISSA electrostatic separator [2] and implantation into silicon strip detectors. The assignment of unknown -decays was made by establishing their genetic position and time correlations with those belonging to known -decay chains. The -decay energies of^228,229Pu were measured to be (7810±20) keV and (7460±30) keV, respectively.