PRODUCTION CAVITIES AND CRYOMODULES FOR A HEAVY ION RE-ACCELERATOR AT MICHIGAN STATE UNIVERSITY

A superconducting linac for re-acceleration of exotic ions is being constructed at Michigan State University (MSU). The re-accelerator will initially be used by the MSU Coupled Cyclotron Facility; it will later become part of the Facility for Rare Isotope Beams at MSU. The re-accelerator will include two types of superconducting quarter-wave resonators (QWRs) to accelerate from 0.6 MeV per nucleon (MeV/u) to up to 3 MeV/u for uranium ("ReA3"), with a subsequent upgrade path to 12 MeV/u ("ReA12"). The QWRs (80.5 MHz, optimum β = 0.041 and 0.085, made from bulk niobium) are similar to the cav- ities used at INFN-Legnaro for ALPI and PIAVE. They in- clude stiffening elements and passive dampers to mitigate fluctuations in the resonant frequency. Eight β = 0.041 QWRs have been fabricated; welding of the helium ves- sels and RF testing is in progress. Another eight β = 0.085 QWRs are needed. Three cryomodules are needed to reach 3 MeV/u. Fabrication and assembly of the first cryomod- ule (the rebuncher, with one β = 0.041 QWR and two su- perconducting solenoids) is complete. This paper covers production efforts, test results so far, and future plans.