Samuel Miller

FRIB Project Status and Beam Instrumentation Challenges

With an average beam power two orders of magnitude higher than operating heavy-ion facilities, the Facility for Rare Isotope Beams (FRIB) stands at the power frontier of the accelerator family. This paper summarizes the status of design, technology development, construction, commissioning, as well as path to operations and upgrades. We highlight beam instrumentation challenges including machine protection of high-power heavy-ion beams and complications of multi-charge-state and multi-ion-species accelerations.

The FRIB Superconducting Linac - Status and Plans

With an average beam power two orders of magnitude higher than operating heavy-ion facilities, the Facility for Rare Isotope Beams (FRIB) stands at the power frontier of the accelerator family. This report summarizes the current design and construction status as well as plans for commissioning, operations, and upgrades.

Design of a FRIB Half-Wave Pre-Production Cryomodule

The driver linac for the Facility for Rare Isotope Beams (FRIB) will require the production of 48 cryomodules (CMs). In addition to the =0.085 quarter-wave CM, FRIB has completed the design of a =0.53 half-wave CM as a pre-production prototype. This CM will qualify the performance of the resonators, fundamental power couplers, tuners, and cryogenic systems of the =0.53 half-wave design. In addition to the successful systems qualification; the =0.53 CM build will also verify the FRIB bottom up assembly and alignment method on a half-wave CM type. The lessons learned from the =0.085 pre-production CM build including valuable fabrication, sourcing, and assembly experience have been applied to the design of =0.53 half-wave CM. This paper will report the design of the =0.53 half-wave CM as well as the CM interfaces within the linac tunnel.

FRIB HWR Tuner Development

During the last two years the HWR pneumatic tuner development at FRIB evolved from the first prototypes to the final production design. A lot of warm testing and several cryogenic integrated tests with cavity were performed to optimize the tuner features. The main challenges included the bellow bushings binding and very tight space limitations for the assembly on the rail. The final design, based on the acquired experience, was prepared in collaboration with ANL and entered the preproduction phase. FIRST PNEUMATIC TUNER PROTOTYPE AT FRIB First pneumatic tuner prototype was prepared in spring 2014 (Fig.1). The design followed ANL guidelines [1]. We started the systematic study of the tuner in June 2014 using a HWR53 cavity. Figure 1: Pneumatic tuner prototype. We used FRIB LLRF controller interfaced with PC to drive the valve system and acquire helium gas pressure and frequency data. For evaluation purposes we developed 3 types of sequences:  Full range scanning with frequency and pressure registration up to 15 cycles per hour (can be executed in superconducting state and nearly critical coupling at room temperature)  Full range scanning up to 150 cycles per hour with pressure registration  Small range (1-2 psi) scanning 1800 cycles per hour with pressure registration. The pressure floor could be changed using the pressure regulator During the first warm testing runs the main part of tuning mechanism including frame, arms and cables seemed to work fine and to be under control. We only had to reinforce the planes as they were flexing and enlarge the spacing for frame to move without touching the arms. We had to concentrate on the bellows lifetime as the most critical parameter for FRIB project. We started with the bellows with 3 guides for the movable flange (Fig. 2). Figure 2: Initial bellows model. We have got one of the bellows broken in the first convolution after 500 full cycles. After that all new bellow flanges are EB welded instead of TIG to reduce the overheating and bellows damage probability, and the profile for welding had been modified. The main problem we encountered was the friction and binding between the guides and the flange. Used testing sequence consisted of about 200-300 full range cycles and about 2000 each small range cycles in at least 3 pressure regions. Several guide bar-bushing combinations and solutions were tested (Fig.3).  Nitronic bar and bushing  Nitronic bar and Bronze bushing  Nitronic bushing and Bronze bar (ANL style)  Nitronic bushing and Bronze bar of larger diameter  Nitronic/Dicronite bushing and Bronze bar  Nitronic/Dicronite bar and bushing  Nitronic/Dicronite bushing and Nitronic bar ___________________________________________ * Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661, the State of Michigan and Michigan State University † stark@frib.msu.edu Proceedings of LINAC2016, East Lansing, MI, USA TUPLR029

FRIB Accelerator: Design and Construction Status

With an average beam power approximately two to three orders of magnitude higher than operating heavy-ion facilities, the Facility for Rare Isotope Beams (FRIB) stands at the power frontier of the accelerator family. This report summarizes the current design and construction status.