Lawrence Berkeley National Laboratory

A high power GeV proton linac has many scientific applications. Recirculating RF linac as anefficient accelerator has been used and proposed to accelerate both electron and muon beams.In this paper, we propose using a multi-pass recirculating RF linac to attain a multi-GeV highpower proton beam. Besides a front-end injector, this linac consists of three type of RF cavitiesthat accelerate the proton beam multiple times from 150 MeV to final multiple GeV energy.A new energy averaged transit time factor is defined to help choose transition energy betweendifferent sections and cavity geometry parameters in the linac design. Using superconductingrecirculating linac significantly reduces the number of RF cavities in the accelerator and lowersconstruction and operational costs of the facility.