Development of a heavy-ion linac based on superconducting interdigital accelerating structures

Four types of superconducting accelerating structures are being developed for use in a low-velocity positive-ion injector linac planned for ATLAS heavy-ion accelerator. A prototype of the first of these, an interdigital four-gap structure, has been completed and tested at accelerating gradients up to 10 MV/m, corresponding to a maximum surface electric field of 40 MV/m and an effective accelerating potential of 1 MV/resonator. The 48.5 MHz resonant cavity has an active length of 10 cm and is designed for particle velocities in the range 0.007c < v < 0.014c. Prototypes of the remaining three resonator types required for the linac are under construction