Alternating-Phase-Focused Linac with Interdigital H-Mode Structure for Medical Injector

A compact injector consisting of a Radio Frequency Quadrupole (RFQ) linac and Interdigital H-mode Drift Tube Linac (IH-DTL) for medical accelerators was designed. A model cavity of IH-DTL was constructed and electric field distributions were measured. The measured distributions were compared with those calculated by a three dimensional field solver. With the comparison, accuracy of the solver was discussed. The RFQ linac has been constructed. The final design of IH-DTL is in progress. Construction of the entire compact injector will be completed by the end of this year, and a beam test will be performed.