A design of a 2.2 MW, CW collector for a high power gyrotron with sweeping coils placed inside the hollow electron beam has been performed. The arrangement of the collector coils which is different compared with presently used collectors in high power gyrotrons have the following advantages:

(1) A faster sweeping rate of the electron beam along the collector surface is possible. Due to that the temperature oscillations at the collector surface related to the sweeping of the electron beam are reduced significantly. This reduces the thermal stresses and the risk of material failure due to creation of cracks.

(2) The small radial size of the collector coils makes it easy to generate a magnetic field distribution which leads to a non-adiabatic electron motion and an increase of the radial spread of the electron beam and a corresponding decrease of the peak power density at the collector wall.