FRIB, East Lansing, Michigan, USA
JLab, Newport News, Virginia, USA
INFN/LNL, Legnaro (PD), Italy
KEK, Ibaraki, Japan
ANL, Lemont, Illinois, USA
TRIUMF, Vancouver, Canada
The Facility for Rare Isotope Beams (FRIB) superconducting (SC) driver linac is designed to accelerate all stable ions including uranium to energies above 200 MeV/u primarily with 46 cryomodules containing 324 quarter-wave resonators (QWR) and half-wave (HWR) resonators. With the newly commissioned helium refrigeration system supplying liquid helium to the QWR and solenoids, heavy ion beams including Ne, Ar, Kr and Xe were accelerated to the charge stripper location above 20 MeV/u with the first linac segment consisting of 15 cryomodules containing 104 QWRs of β=0.041 and 0.085 and 39 solenoids. Installation of cryomodules with β=0.29 and 0.53 HWRs is proceeding in parallel. Development of β=0.65 elliptical resonators is on-going supporting the FRIB energy upgrade to 400 MeV/u. This paper summarizes the SC-linac installation and phased commissioning status that is on schedule and on budget to the FRIB project.
FRIB, East Lansing, Michigan, USA
INFN/LNL, Legnaro (PD), Italy
KEK, Ibaraki, Japan
TRIUMF, Vancouver, Canada
FRIB cryomodule design has a feature: solenoid package(s) and local magnetic shields in the cryomodule. In this design, exposing SRF cavities to a very strong fringe field from the solenoid is concerned. A tangled issue between solenoid package design and magnetic shield one has to be resolved. FRIB made intensive studies, designed, prototyped, validated the solenoid packages and magnetic shields, and finally certified them in the bunker test. This paper reports activity results, and LS1 commissioning results in FRIB tunnel. This is a FRIB success story.
FRIB, East Lansing, Michigan, USA
The Facility for Rare Isotope Beams (FRIB) is a heavy ion accelerator that produces rare isotopes for science. To achieve the high beam quality of FRIB¿s linear accelera-tor (linac), the superconducting solenoid packages are employed for beam focusing and steering in the cry-omodule. The solenoid packages will generate a maxi-mum 8T focusing field along beam direction and 0.124 T bending field for beam steering. A total 74 solenoid packages have been produced and the first segment linac (LS1) of FRIB have completed commissioning and beam acceleration. In this paper, the cryomodule¿s solenoid commissioning and the performance of the LS1 linac are introduced. The lessons learned during the testing will also be presented.
FRIB, East Lansing, Michigan, USA
INFN/LNL, Legnaro (PD), Italy
ANL, Lemont, Illinois, USA
JLab, Newport News, Virginia, USA
The superconducting driver linac for the Facility for Rare Isotope Beams (FRIB) requires the production of 46 cryomodules. Design is complete on all six cryomodule types which utilize four superconducting radio frequency (SRF) cavity designs and superconducting solenoids. The FRIB cryomodules utilize an innovative bottom up approach to achieve alignment tolerance and simplify production assembly. The cryomodule testing includes qualification of the resonator performance, fundamental power couplers, tuners, and cryogenic systems. FRIB beam commissioning has been performed on 15 cryomodules in the FRIB and validates the FRIB cryomodule bottom up assembly and alignment method. This paper will report the FRIB cryomodule design, performance, and the alignment results and their impact on beam commissioning.
Michigan State University, East Lansing, Michigan, USA
NHMFL, Tallahassee, Florida, USA
ASC, Tallahassee, Florida, USA
FRIB, East Lansing, Michigan, USA
NSCL, East Lansing, Michigan, USA
Trapped micro-Tesla levels of magnetic flux degrade the performance of Nb superconducting radio frequency (SRF) accelerators. Recent studies have revisited the role of small deformation (dislocation substructure influence) on cavity performance. However, the link between microstructural defects and mechanisms leading to poor performance is still unresolved. To examine the mechanism of flux pinning by dislocations and grain boundaries, systematic studies on bi-crystal Nb tensile samples were designed with strategically chosen orientation relationships between neighboring crystals with respect to the grain boundaries. Laue X-ray diffraction and electron backscatter diffraction analysis was used to measure crystal orientations of a large-grain Nb slice, from which the bi-crystals were extracted. Dislocation structures near the grain boundaries were characterized before and after 5% tensile deformation using electron channeling contrast imaging (ECCI), after which the magnetic flux behavior was observed using cryogenic magneto-optical imaging (MOI). We discuss the conditions under which we observe increased flux pinning in regions of high dislocation density.
NSCL, East Lansing, Michigan, USA
FRIB, East Lansing, Michigan, USA
SLAC, Menlo Park, California, USA
The Facility for Rare Isotope Beams (FRIB), located on the campus of Michigan State University (MSU) will require 324 Superconducting Radio Frequency (SRF) cavities in the driver linac. Four types of cavities of two classes, quarter-wave (β=0.041 and 0.085) and half-wave (β=0.29 and 0.53), will be housed in 46 cryomodules. To date, FRIB has tested over 300 cavities in vertical Dewar tests as part of the certification procedures. Incoming cavities, fabricated in industry, are sequenced through acceptance inspection and checked for non-conformance. If accepted, the cavities are processed, assembled onto a vertical test stand, and cold tested. A large database of cavity surface images has been collected with the aid of a borescope camera. Borescope inspection is a standard step that is performed at incoming inspection, post-acid bulk etch, and after failed tests (if necessary) for each cavity, in order to locate any non-conformances. Findings of surface defects relating to degraded cavity performance will be presented.