New test results of 170 GHz/1MW/50%/CW gyrotron for ITER

The development of 170 GHz/1 MW/ 50%/CW gyrotron for ITER has been in progress in Russia. Recent test results of the last gyrotron version are presented. Stable output power of 0.5-0.6 MW was obtained for 300-s pulse duration limited by capability of the main power supply of that time. For output power of 0.9-0.95 MW the maximal pulse duration of 102 s was mainly limited by instability of gyrotron protection system and imperfection of power transmission line. Total gyrotron efficiency was about 50%. Stray radiation near 5% of radiated power was measured. After testing facility improvement and gyrotron opening and reassembling gyrotron test will be continued.