Development of the heavy ion RFQ for CAFE2

A radio frequency quadrupole (RFQ) accelerator which accelerates particles with a mass-to-charge ratio up to 3 to over 1.33 MeV/u was developed. This RFQ was designed based on the existing 162.5 MHz solid-state power sources of the Chinese Accelerator Driven System (C-ADS) injector II. The frequency is relatively high to a heavy ion RFQ which means a weak transverse focusing strength and brings challenges to the beam loss and quality control. The average radius r0 of the RFQ was appropriately chosen to make a compromise between the transverse focusing strength and the maximum surface field. The beam dynamics parameters were carefully optimized to improve the quality of the RFQ output beam so that the beam could be well transported in the following superconducting structure. Beam dynamics simulations and an error study have been performed to evaluate the RFQ and a method which is more suitable for the analyses of small acceptance RFQs has been adopted. And the results of the beam commissioning have been proved to agree well with the simulations.