Acceleration test of the folded-coaxial RFQ linac for the RILAC

A new injector system for the RIKEN heavy-ion linac (RILAC) has been constructed, which consists of a variable-frequency RFQ and an 18-GHz ECR ion source. The RFQ, based on a folded-coaxial resonator with a movable shorting plate, accelerates ions with mass-to-charge ratios of 6 to 26 at up to 450 keV per charge in the cw mode by varying the resonant frequency from 17.7 to 39.2 MHz. Beam tests of the RILAC and the ring cyclotron (RRC) were successfully performed with the new injector system. The beam intensity from the RRC as well as the transmission efficiency through the RILAC has been greatly improved. This paper describes the performance of the RFQ and the results of the acceleration tests.