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 and installation of the Californium Rare Ion Breeder Upgrade (CARIBU) for ATLAS facility is nearly complete. 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 bred 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. We expect first beam tests from the project by May 2009. The facility design and first results of beam studies using a weaker 2.2 and 80 mCi sources will be presented in this report. Plans for installation of the 1 Ci source will be discussed.
ANL, Argonne
Funding: This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357.
The ongoing energy upgrade of the heavy-ion linac ATLAS at ANL includes a new cryomodule containing seven 109MHz β=0.15 quarter-wave superconducting cavities to provide an additional 15 MV voltage. Several new features have been incorporated into both the cavity and cryomodule design. For example, the cryomodule separates the cavity vacuum space from the insulating vacuum, a first for TEM cavities. The cavities are designed in order to cancel the beam steering effect due to the RF field. Clean techniques have been applied to achieve low-particulate rf surfaces and are essential for reliable long-term high-gradient operation. The sealed clean subassembly consisting of cavities, beam spools, beam valves, couplers, vacuum manifold, and support frame has been attached to the top plate of the cryomodule outside the clean room. Initial commissioning results are presented. The module was designed and built as a prototype for the Facility for Rare Isotope Beams (FRIB) driver linac, however, a similar design can be effectively used in the front-end of SC proton linacs based on TEM-class SC cavities.
ANL, Argonne
TechSource, Santa Fe
CLASSE, Ithaca
Funding: This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357.
A new cryomodule with seven low-beta superconducting radio frequency (SRF) quarter wave niobium cavities has been designed and constructed as an energy upgrade project for the ATLAS accelerator at Argonne National Laboratory. The technology developed for this project is the basis for the next generation superconducting heavy ion accelerators. This paper will discuss the methods employed to tune the cavities eigenfrequency to match the accelerator master oscillator frequency and the development of the RF systems used to both drive the cavity and keep the cavity phase locked during operation.