Argonne National Laboratory

Completion of the first GRETINA Campaign at ATLAS

June 17, 2015

The first campaign of the GRETINA array at the ATLAS facility was completed on June 15, 2015. Over a little more than a year, a total of 130 days of beam time was devoted to measurements with GRETINA for 18 PAC-approved experiments. A large fraction of the research program was dedicated to Coulomb excitation measurements where the device was coupled with the CHICO-2 array of PPAC counters for particle detection. This part of the program focused on the nature of collective excitations in 72,76Ge, the onset of collectivity in 98Zr, the search for evidence of triaxiality in neutron-rich 100Zr, 106Mo and 112Ru, and the determination of octupole strength in 144,146Ba, 146Ce and 146La. The same GRETINA + CHICO2 combination was also used in measurements probing the properties of neutron-rich nuclei with deep-inelastic reactions. The Phoswich wall, an array dedicated to the detection of light, charged particles was used in a number of experiments probing single-particle properties in nuclei of the mass A ~ 30 and A ~ 140 regions as well as the nature of the enhancement of the low-energy photon strength function in A ~ 50 nuclei. Finally, a number of measurements was dedicated to studies of the intrinsic capabilities of GRETINA itself (comparison with Gammasphere, characterization of the ability to measure polarization, count rate capabilities, etc.). More than 100 scientists from 15 institutions participated in this successful first campaign at ATLAS.