摘要
Two room temperature quarter wave resonator(QWR)buncher cavities with frequency of 162.5 MHz havebeen designed as parts of the medium energy beam transport line(MEBT1)for injectorⅡin China AcceleratorDriven Sub-critical System (C-ADS) project in order to focus the beam longitudinally, thus keeping the bunchlength and matching the beam to the acceptance of the superconducting linac.Buncher is one of major equipments in MEBT1. Fig. 1 shows the layout of the MEBT1. Its structure directlyaffects the performance of MEBT1. Buncher cavity takes an open-ended quarter-wavelength coaxial line cylindertype structure, the mechanical design of buncher cavity was done according to the physical design, adequate considerationought to be given to the factors of electromagnetic field distribution, power coupling, frequency tuning,cavity cooling and manufacturing, and so on.