CARIBU:
a new facility for the study of neutron-rich isotopes G.
Savard Argonne
National Laboratory and University of Chicago, USA
The
Californium Rare Ion Breeder Upgrade (CARIBU) of the ATLAS
superconducting linac facility provides 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 252Cf source,
thermalized and collected into a low-energy particle beam by a
helium gas catcher, mass analyzed by an isobar separator, and
charge breed to higher charge states for acceleration in ATLAS. The method described is
fast and universal and short-lived isotope yield scale essentially
with Californium fission yields. The
facility has ramped up with first operation with a weaker 2.5 mCi
source and now a 100 mCi source which has yielded extracted
low-energy mass separated radioactive beams at intensities in
excess of 100000 ions per second. Radioactive beams have been
charge bred with an efficiency of about 12% and reaccelerated to 6
MeV/u. Commissioning
results, together with the results from first astrophysics
experiments at CARIBU using the beams from the 100 mCi source will
be presented. The
final 1 Ci source has been fabricated and its installation is in
preparation. This
work was supported by the US DOE, Office of Nuclear Physics, under
contract DE-AC02-06CH11357.