The IH-RFQ for HIRFL-CSR injector

A new linac injector CSR-LINAC for the Cooler Storage Ring of the Heavy Ion Research Facility in Lanzhou (HIRFL-CSR) is proposed to improve the performance of the HIRFL. As a key component of the CSR-LINAC, the 108.48-MHz radio frequency quadrupole (RFQ) is under design at the Institute of Modern Physics. Heavy ions with mass-to-charge ratios of 3-7 will be accelerated from 4 to 300 keV/u by the RFQ. In the beam dynamics design, the New Four-Section Procedure is adopted to improve the transmission efficiency and obtain a compact structure. In this paper, a transmission efficiency of 98.0% in the 3.07-m-long cavity was obtained. The Interdigital H-type structure is employed because of its mechanical stability and high shunt impedance. The RF performance of the cavity is investigated by the electromagnetic simulation. The optimized results of the electric field to meet the beam dynamics requirements are presented in this paper.