• R.C. Pardo, S.I. Baker, C.N. Davids, A. Levand, D. Peterson, D.R. Phillips, G. Savard, T. Sun, R.C. Vondrasek, B. Zabransky, G.P. Zinkann
  ANL, Argonne

Funding: This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357.

Construction of the DOE Californium Rare Ion Breeder Upgrade (CARIBU) for the ATLAS facility is expected to be completed by the end of 2008 and commissioning should be well along by the time of the conference. The facility will use fission fragments from a 1 Ci 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. In addition, unaccelerated beams will be available for trap and laser probe studies. Expected yields of accelerated beams are up to ~5x10⁵ (10⁷ to traps) far-from-stability ions per second on target. The facility design and first results of beam acceleration using a weaker 80 mCi source will be presented in this paper and plans for installation of the 1 Ci source will be discussed.

Slides

• C.N. Davids, D. Peterson
  ANL, Argonne

Funding: This work was supported between the UChicago, Argonne, LLC and the Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357.

We have designed a compact high-resolution isobar separator for CARIBU* at the ATLAS accelerator facility at Argonne National Laboratory. Fission fragments from a 252Cf source are thermalized, cooled, and accelerated to 50 keV. The small longitudinal emittance of this cooled beam allows the use of pure magnetic dispersion for mass analysis. Using two 60° bending magnets, two electrostatic quadrupole doublets, and two electrostatic quadrupole singlets in a symmetric combination, a first-order mass resolution of 22,400 is calculated. Aberration correction up to 5th order is accomplished by means of two electrostatic hexapole singlets and a 48-rod electrostatic multipole lens with hexapole, octupole, decapole, and dodecapole components. The fields with critical tolerances are the quadrupole singlets (±1x10-3) and the hexapole component of the multipole (±2x10-3). Ion-optics calculations were performed using the program COSY INFINITY**. The resulting ion trajectories and mass spectra will be presented. All electrostatic elements have been constructed, and delivery of the magnets is expected in early 2009. A progress report on installation and commissioning will be presented.

*See invited talk by R. Pardo at this conference.
**Version 8.1, M. Berz et al., (2002).