Collector design studies for a 1 MW cylindrical-cavity and a 4 MW coaxial-cavity gyrotron

In this paper we will present design studies for the collectors and collector sweeping systems of two different high power CW gyrotrons: a) The 1 MW 170 GHz cylindrical-cavity gyrotron for ITER (the backup solution for the 2 MW coaxial-cavity gyrotron), which should have the capability to be operated in modulated mode with a resulting total collector loading of up to 1.5 MW. b) A 4 MW 170 GHz coaxial-cavity gyrotron which at present is in the state of a design study. The total collector loading exceeds 4.5 MW which makes the process of collector layout a quite challenging task.