Study of 14 GHz VLEPP klystron with RF absorbing drift tubes

Results of experimental study of a wide-aperture relativistic klystron for VLEPP are presented. Investigations have been performed using the driving beam of the JINR LIA-3000 induction accelerator. To suppress self-excitation parasitic modes we have used technique of RF absorbing drift tubes. We have obtained 75 MW of output power in a long pulse (250 ns) and 100 MW in a short pulse (50 ns).