Beam Commissioning Of The Coupled Rfq-Sfrfq Cavity

We developed a novel compact structure, called a Coupled RFQ-SFRFQ (CRS), to accelerate a 0.8 MeV helium beam for a materials irradiation project. A high accelerating efficiency was achieved by replacing the accelerating section of the radio frequency quadrupole (RFQ) with a separated-function radio frequency quadrupole (SFRFQ) structure, in a single cavity. Following the electromagnetic simulations, RF measurement of the CRS cavity was performed, including low RF power and high RF power measurement. Recently, beam experiments on the CRS linac indicated that the maximum accelerated beam current could reach 2 mA with an energy of 0.8 MeV and energy spread (FWHM) of 3.1%. The experimental measurement results showed good consistency with the beam dynamics simulations.