FRIB, East Lansing, Michigan, USA
The Facility for Rare Isotope Beams (FRIB) is ready to start construction. The facility will utilize a high-intensity, heavy-ion driver linac to provide stable ion beams from protons to uranium up to energies of >200 MeV/u and at a beam power of up to 400 kW. The superconducting cw linac consists of 330 individual low-beta (β = 0.041, 0.085, 0.29, and 0.53 at 80.5 MHz and 322 MHz) cavities in 49 cryomodules operating at 2 K. This paper discusses the current development status of the project with emphasis on the linac SRF acquisition. SRF coldmass and cryomodule component designs are briefly summarized. A SRF production facility, currently under construction, is described.
FRIB, East Lansing, USA
The first prototypes of the β=0.53 and β=0.29 HWR production design cavities for FRIB were fabricated early this year by Roark Manufacturing Company and delivered to MSU. These cavities have undergone an extensive evaluation program to verify both mechanical and RF performance before proceeding with fabrication of a pre-production run of 10 cavities. Results from physical inspections, warm RF measurements, chemical processing, and cryogenic vertical testing will be presented.
NSCL, East Lansing, Michigan, USA
FRIB, East Lansing, Michigan, USA
INFN/LNL, Legnaro (PD), Italy
The 80.5 MHz, β=0.085 QWR production cavities for the ReA3 project at MSU have initially shown puzzling behavior and unexpected lack of performance. This was due to a combination of design problems and subtle mechanical effects which have been pointed out during a brief but intense testing campaign made by the FRIB SRF group. The same cavities could be eventually refurbished and brought to performance well above original specifications. This work will be presented with emphasis to the technical problems encountered, their diagnosis and the adopted solutions.
FRIB, East Lansing, USA
The SRF community faces difficulties finding repeatable, quality copper plating for fundamental power coupler (FPC) components. The copper plating of ten small custom bellows of β=0.085 Quarter-Wave Resonator (QWR) variable couplers for the ReAccelerator project has presented technical challenges. An improvement plan has been established and includes: better defining plating requirements and specification, creating testing processes to assure plating quality (Acceptance Criteria Listing (ACL)), identify viable plating vendors, develop clean, robust plating fixtures, procedures and quality assurance steps with multiple vendors, and perform ACL testing on plated bellows. A total of 24 prototype and production plated bellows are analyzed through acceptance testing, which include a vacuum leak check, tape test, 1000 psi water rinse, thermal cycle at 77K, borescope inspection and final leak check. Select bellows have been processed and tested with a quarter-wave resonator. A summary of the plating improvement program, plated bellows acceptance statistics, and RF test results will be reported.