title: Operational experience with the Argonne National Laboratory Californium Rare Ion Breeder Upgrade facility and electron cyclotron resonance charge breeder.
abstract: The Californium Rare Ion Breeder Upgrade (CARIBU) of the Argonne National Laboratory Argonne Tandem Linac Accelerator System (ATLAS) facility provides low-energy and accelerated neutron-rich radioactive beams to address key nuclear physics and astrophysics questions. A 350 mCi (252)Cf source produces fission fragments which are thermalized and collected by a helium gas catcher into a low-energy particle beam with a charge of 1+ or 2+. An electron cyclotron resonance (ECR) ion source functions as a charge breeder in order to raise the ion charge sufficiently for acceleration in the ATLAS linac. The ECR charge breeder has achieved stable beam charge breeding efficiencies of 10.1% for (23)Na(7+), 17.9% for (39)K(10+), 15.6% for (84)Kr(17+), and 12.4% for (133)Cs(27+). For the radioactive beams, a charge breeding efficiency of 11.7% has been achieved for (143)Cs(27+) and 14.7% for (143)Ba(27+). The typical breeding times are 10 ms/charge state, but the source can be tuned such that this value increases to 100 ms/charge state with the best breeding efficiency corresponding to the longest breeding times-the variation of efficiencies with breeding time will be discussed. Efforts have been made to characterize and reduce the background contaminants present in the ion beam through judicious choice of q/m combinations. Methods of background reduction are being investigated based upon plasma chamber cleaning and vacuum practices.
authors.affiliation: Physics Division, Argonne National Laboratory, Lemont, Illinois 60439, USA.
authors.forename: R
authors.initials: R
authors.lastname: Vondrasek
authors.affiliation: Physics Division, Argonne National Laboratory, Lemont, Illinois 60439, USA.
authors.forename: J
authors.initials: J
authors.lastname: Clark
authors.affiliation: Physics Division, Argonne National Laboratory, Lemont, Illinois 60439, USA.
authors.forename: A
authors.initials: A
authors.lastname: Levand
authors.affiliation: Physics Division, Argonne National Laboratory, Lemont, Illinois 60439, USA.
authors.forename: T
authors.initials: T
authors.lastname: Palchan
authors.affiliation: Physics Division, Argonne National Laboratory, Lemont, Illinois 60439, USA.
authors.forename: R
authors.initials: R
authors.lastname: Pardo
authors.affiliation: Physics Division, Argonne National Laboratory, Lemont, Illinois 60439, USA.
authors.forename: G
authors.initials: G
authors.lastname: Savard
authors.affiliation: Physics Division, Argonne National Laboratory, Lemont, Illinois 60439, USA.
authors.forename: R
authors.initials: R
authors.lastname: Scott