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Norton, D.

Paper Title Page
THP093 Power Coupler and Tuner Development for Superconducting Quarter-Wave Resonators 1005
  • J. Wlodarczak, P. Glennon, W. Hartung, M. Hodek, M.J. Johnson, D. Norton, J. Popielarski
    NSCL, East Lansing, Michigan

The construction of a reaccelerator for secondary ion beams is currently underway at the National Superconducting Cyclotron Laboratory (NSCL). The reaccelerator linac will use superconducting quarter-wave resonators (QWR) operating at 80.5 MHz with beta = 0.041 and beta = 0.085. A coaxial probe-type rf fundamental power coupler (FPC) will be used for both QWR types. The power coupler makes use of a commercially-available feedthrough to minimize the cost. The FPC has been simulated and optimized for operation at 80.5 MHz using a finite element electromagnetics code. Prototype FPC have been fabricated and conditioned with traveling wave and standing wave power using a 1 kW amplifier. A niobium tuning plate is incorporated into the bottom flange of the QWR. The tuner is actuated by a stepping motor for slow (coarse) tuning and a stacked piezoelectric element in series for fast (fine) tuning. A prototype tuner for the beta = 0.041 QWR has been tested on the cavity at room temperature. This paper will cover the design, fabrication, and testing of the prototype coupler and tuner.

THP033 Superconducting Quarter-Wave Resonator Cavity and Cryomodule Development for a Heavy Ion Re-accelerator 854
  • W. Hartung, J. Bierwagen, S. Bricker, C. Compton, J. DeLauter, P. Glennon, M. Hodek, M.J. Johnson, F. Marti, P.S. Miller, D. Norton, J. Popielarski, L. Popielarski, D. Sanderson, J. Wlodarczak, R.C. York
    NSCL, East Lansing, Michigan
  • A. Facco
    INFN/LNL, Legnaro, Padova
  • E.N. Zaplatin
    FZJ, Jülich

A superconducting linac is being planned for re-acceleration of exotic ions produced by the Coupled Cyclotron Facility at Michigan State University. The re-accelerator will include a gas stopper, a charge breeder, a normal conducting radio-frequency quadrupole, and two types of superconducting quarter-wave resonators (QWRs) for re-acceleration to energies of up to 3 MeV per nucleon initially, with a subsequent upgrade path to 12 MeV per nucleon. The QWRs (80.5 MHz, optimum beta = 0.041 and 0.085, made from bulk niobium) are similar to existing cavities presently used at INFN-Legnaro. The re-accelerator's cryomodules will accommodate up to 8 cavities, along with superconducting solenoids for focussing. Active and passive shielding is required to ensure that the solenoids' field does not degrade the cavity performance. First prototypes of both QWR types have been fabricated and tested. A prototype solenoid has been procured and tested. A test cryomodule has been fabricated: one QWR, one solenoid, and two other beam line elements have been installed inside. This paper will cover the re-accelerator cavity and cryomodule prototyping efforts, results so far, and future plans.


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