FRIB, East Lansing, Michigan, USA
The FRIB superconducting linac will deliver all heavy ion beams with energy above 200 MeV/u, and beam power on target up to 400 kW for generation of short lived isotopes. Beam commissioning is the first step to prepare and tune the superconducting linac for high power operation. A staged beam commissioning plan of the FRIB linac is developed, and complete beam tuning practices segment by segment through the entire linac are introduced, which include phase scan signature matching of the superconducting cavities, longitudinal beam matching, transverse matching with horizontal-vertical beam coupling, and beam optics corrections of achromatic and isochronous folding segments up to the second order for acceleration and transport of multi charge state beams.
FRIB, East Lansing, Michigan, USA
JLab, Newport News, Virginia, USA
INFN/LNL, Legnaro (PD), Italy
KEK, Ibaraki, Japan
ANL, Argonne, Illinois, USA
TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada
The FRIB driver linac accelerates all the stable ion beams including uranium over 200 MeV/u with a CW beam power of 400 kW in order to produce isotopes as rare as possible. Except for 0.5 MeV/u RFQ, the linac is making use of superconducting (SC) RF technology. The beam power, which is an order of 2.5 as high as those of existing SC heavy ion linac, gives rise to many technical challenges as well as beam physics related ones. In particular, the uranium beam loss power density is approximately 30 times as high as the proton one with the same beam energy per nucleon and the same beam power. For this reason, the machine protection system needs a special care. Another example of the technical challenges is to install beam focusing solenoid as close as possible to SC cavities in order to ensure the frequent beam focusing both longitudinally and transversely. The talk reviews all these challenges with development results of their mitigation as well as construction status.
