Demi-disk travelling wave accelerating structure

The dark current in a normal disk-loaded accelerating structure is one of the main obstacles which limit the accelerating gradient going higher. In this paper a demi-disk accelerating structure is proposed in order to reduce the dark current. Its transverse RF focusing forces can reduce the effects of wakefields on the beam emittance growth which is preferable in future linear colliders. 3D program PRIAM has been used to calculate the field distributions and the dispersion curves of this structure. Estimations of the trajectories of the field emission electrons have been done.<>