Status of the SUNY superconducting RFQ

An RFQ (radio-frequency quadrupole) resonator that is a prototype for a chain of six short (approximately 0.5-m-long), superconducting (Pb plated Cu), 50-MHz resonators designed to accelerate a beam from β = 0.01 to 0.05 is being developed. The chain accepts a prebunched beam to save on superconducting length. The resonators are four-rod type with vane-like electrodes. The prototype resonator is designed to accelerate ions of q/A = 1/6 from β = 0.030 to 0.36, operating at a peak surface electric field of 16 MV/m. The electrodes have a rather high modulation parameter of 4 and a wide aperture of 1.57-cm radius. These values are chosen to maximize the accelerating field (E_a) for a given peak surface electric field (E_s). At the design value of E_s = 16 MV/m, the resonator is estimated to have E_a = 2.0 MV/m, stored energy of 4 J, peak surface magnetic field of 360 G, and inter-vane voltage of 0.42 MV. Results of RF tests on this prototype resonator are presented.