Identification of neutron-deficient isotopes226,227Np

The neutron-deficient isotopes226Np and227Np were produced in the bombardment of a 380μg/cm2209Bi target with22Ne projectiles at an incident beam energy of 5.5 MeV/u. They were identified using the α-α time-correlation method /1/.226Np was found to decay with Eα=(8044±20) keV andT1/2=(31±8) ms. For227Np two α-lines were observed at (7650±20) keV and (7677±20) keV with a half-life of (510±60) ms. The gas-filled separator NASE installed at GSI Darmstadt was used to separate the evaporation residues inflight.