DEVELOPMENT OF THE DEMOUNTABLE DAMPED CAVITY

We have designed a new HOM free cavity named Demountable Damped Cavity (DDC) as an ILC R&D. DDC has two design concepts. The first one is an axial symmetry to eliminate kick off effect by HOM coupler itself. DDC is applied coaxial structure along the beam axis to make strong coupling with HOMs. HOMs are damped in RF absorber at the end of coaxial waveguide and the accelerating mode is reflected by the choke filter mounted nearby the end cell. The second concept is demountable structure which can make cleaning the end group easy in order to suppress the Q-slope problem at high field. In this paper, we will report about a RF absorber shape, thermal structure, 9 Cell cavity shape and preliminary vertical test result on the single cell DDC structure.