DESIGN AND MEASUREMENT OF DOUBLE GAP BUNCHER CAVITY PROPOSED FOR REDUCTION OF X-RAY RADIATION

X-ray radiation from accelerating cavities can be serious problem not only in high energy section but also in certain low energy system including beam matching section with buncher cavity. In this paper we propose a double gap buncher cavity design for low energy part of H- ion accelerators which can reduce X-ray radiation. The cavity utilizes Transverse Magnetic (TM) mode at about 400MHz as the operating mode. A drift tube supported by a stem in the cavity can form two gaps that can divide the required gap voltage to a half per each gap. Lower peak field can be realized since this double gap cavity can avoid sharp geometry. 3D simulation is utilized to address the analysis of non-axisymmetric structure. An Aluminum scaled model is built and tested with low power measurement. The measured results are in good agreement with simulations.