FRIB, East Lansing, Michigan, USA
The Facility for Rare Isotope Beams (FRIB) will utilize a powerful, superconducting heavy-ion driver linac to provide stable ion beams from protons to uranium, at energies of > 200 MeV/u at a beam power of up to 400 kW. ECR ion sources installed above ground will be used to provide highly charged ions, that will be transported into the linac tunnel approx. 10 m below ground. For the heaviest ions, two charge states will be accelerated to about 0.5 MeV/u using a room-temperature 80.5 MHz RFQ and injected into a superconducting cw linac, consisting of 112 quarter-wave (80.5 MHz) and 229 half-wavelength (322 MHz) cavities, installed inside 52 cryomodules operating at 2K. A single stripper section will be located at about 17 MeV/u (for uranium). Transverse focusing along the linac will be achieved by 9 T superconducting solenoids within the same cryostat as the superconducting rf accelerating structures. This paper describes the matured linac design, as the project is progressing towards a Department of Energy performance baseline definition in 2012. Development status of the linac subcomponents are presented with emphasis on the superconducting RF components.
FRIB, East Lansing, Michigan, USA
A third generation medium velocity Half Wave Resonator (HWR) is in the final stages of design at Michigan State University (MSU) for use in the Facility for Rare Isotope Beams (FRIB) driver linac. The cavity is being designed to deliver 1.9 MV accelerating voltage reliably, with on optimum β=0.29. The aim is to reduce significantly the peak magnetic field from the first and second generation designs without changing the cryostat design and the linac layout. The design effort optimizes the surface fields for reliable operation but also considers frequency stability and tunability altogether with straightforward fabrication and surface preparation procedures. The electromagnetic and mechanical design started from an existing design and incorporated lessons learned from the MSU developed 322 MHz HWR’s for β=0.53. The third generation cavity has a similar shape but a different design of the beam port flanges which maximizes the available space for the outer conductor.
FRIB, East Lansing, Michigan, USA
Superconducting quarter-wave resonators and half-wave resonators are being prototyped and fabricated at Michigan State University (MSU) in effort to support the Facility for Rare Isotope Beams (FRIB) project. FRIB requires a 200 MeV per nucleon driver linac, operating 345 resonators at two frequencies (80.5 and 322 MHz) and four betas (0.041, 0.085, 0.29, and 0.53). FRIB cavity development work is underway, with the prototyping of all four resonators, including helium vessel design, stiffening strategy, and tuner interface. In addition, the acquisition strategy for FRIB resonators is being finalized, and the technology transfer program is being initiated. The status of the resonator production effort will be presented in this paper, including an overview of the acquisition strategy for FRIB.
FRIB, East Lansing, Michigan, USA
Michigan State University is developing and testing quarter wave resonators for a superconducting linac which will be used to reaccelerate exotic ions to 3 MeV per nucleon or higher (ReA3). Eight quarter wave resonators with an optimum velocity of β = v/c = 0.085 and a resonant frequency of 80.5 MHz are required for the third cryomodule, which will complete the first stage of the reaccelerator linac. Approximately 100 additional β = 0.085 resonators of the same design will be required for the Facility for Rare Isotope Beams (FRIB). Results of Dewar testing to characterize the RF performance of the resonators will be presented in this paper.
NSCL, East Lansing, Michigan, USA
FRIB, East Lansing, Michigan, USA
FRIB, East Lansing, Michigan, USA
INFN/LNL, Legnaro (PD), Italy
A medium velocity half wave resonator has been designed at the Facility for Rare Isotope Beams (FRIB) at Michigan State University (MSU) for use in a heavy ion linac. The cavity is designed to provide 3.7 MV of accelerating voltage at an optimum β = v/c = 0.53. The cavity was designed for manufacturing recommendations based on previous design as well as for stiffness, tunability, assembly, and cleaning. Finite Element Analysis simulations were performed for modal analysis, bath pressure sensitivity, Lorentz Force detuning, tuner stiffness, and tuning range. Industry prototyping is planned to confirm tolerances and fabrication processes. A tuner prototype has also been built. The helium vessel and power coupler have been designed and fabricated and will be adapted to the new cavity design.