Commissioning Experience with Caribu

The Californium Rare Ion Breeder Upgrade (CARIBU) of the ATLAS superconducting linac facility aims at providing low-energy and reaccelerated neutron-rich radioactive beams to address key nuclear physics and astrophysics questions. These beams are obtained from fission fragments of a Cf-252 source, thermalized and collected into a low-energy particle beam by a helium gas catcher, mass analyzed by an isobar separator, and charge bred with an ECR ion source to higher charge states for acceleration in ATLAS. The facility has ramped up operation from an initial 2.5 mCi source to the present 55 mCi source. A 500 mCi source has been produced at Oak Ridge National Laboratory and is expected to be ready for installation in mid-2012. Low-energy mass separated radioactive beams have been extracted, charge bred with a 10% efficiency, reaccelerated to 6 MeV/u, and delivered to GAMMASPHERE for beta decay studies. The Canadian Penning Trap (CPT) mass spectrometer has been relocated to the CARIBU low-energy beam line. Mass measurements on over 60 neutron-rich nuclei have already been performed and additional measurements are underway. In addition, a new tape station for beta decay studies has just been commissioned.