The regions around the doubly magic nuclei 100Sn and 78Ni are of great interest from a nuclear structure standpoint. These nuclei also play a key role in the astrophysical rp- and r-processes, respectively. Recently, nuclei in these regions were studied at the Coupled Cyclotron Facility at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University. © 2004 Elsevier B.V. All rights reserved.

The regions around the doubly magic nuclei 100Sn and 78Ni are of great interest from a nuclear structure standpoint. These nuclei also play a key role in the astrophysical rp- and r-processes, respectively. Recently, nuclei in these regions were studied at the Coupled Cyclotron Facility at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University.

Shell model calculations have been performed for low-excitation states in the Zr isotopes between 90Zr and 96Zr with an emphasis on the g factors and electromagnetic decay rates for the lowest 2+ and 3- states. Overall the 2+ states are reasonably well described. In contrast, the 3- states present a puzzle because the measured g factors imply a single-particle configuration whereas the experimental E3 transition rates imply collective structures that cannot be explained by shell model calculations. A consistent description of the 3 - states in 90Zr and 96Zr is sought in terms of coupling between the single-particle structure and a collective octupole vibration.

The low-energy levels of 120Pd74 were populated by ? decay of 120Rh75, which was produced via projectile fragmentation of a 136Xe82 beam at 120 MeV/nucleon. Delayed ?-gated ? rays with energies of 438 and 618 keV were observed in coincidence with 120Rh75 fragments and assigned to the 21+ ? 0+ and 41+ ? 21+ transitions, respectively, in 120Pd74. Isomeric ?-ray transitions are also reported for 120Rh75 and 126Cd78. The low-energy structure of 120Pd74 shows remarkable similarity to those of the isotopic 108Pd62 and isotonic 128Xe74 suggesting that these nuclides share the same Z=50 and N=82 closed shell structures with neutron-rich 120Pd 74.

The g factor of the first 2+ state of radioactive 76Kr (T1/2=14.8 h) has been measured, extending the systematics of the previously measured stable 78,80,82,84,86Kr isotopes. The measurement was performed with a radioactive 76Kr ion beam applying projectile Coulomb excitation in inverse kinematics combined with the transient magnetic field technique. The 76Kr beam was produced and accelerated in batch mode (re-cyclotron method) at the Lawrence Berkeley National Laboratory 88-Inch Cyclotron. A total of three production and acceleration cycles yielded six hours of beam on target with peak rates of 108 particles/s. About 5.6×104 particle-? coincidence events were recorded. The g factor g(76Kr;2 +1)=+0.37(11) was obtained by direct comparison to the known g(78Kr;2+1) value re-measured immediately after the 76Kr runs with the same setup and under almost identical kinematic conditions. © 2004 Elsevier B.V. All rights reserved.

A batch mode process has been developed to produce a 76Kr (T1/2 = 14.8 h) radioactive ion beam at the Lawrence Berkeley National Laboratory 88-in. Cyclotron. First, a 6 particle ?A ? beam is run for 17 h to produce approximately 101476Kr atoms via the reaction 74Se(?, 2n)76Kr. Then, the krypton is separated from the target material and injected into the AECR-U ion source. Beam intensities as high as 3 × 108 particles per second are observed with an integrated beam current of 6(2) × 1011 particles per 24-h batch cycle. © 2004 Published by Elsevier B.V.