Progress update on CPI 500 kW and 1 MW, multi-second-pulsed gyrotrons

Three programs are underway to deliver long-pulse or CW gyrotrons with output power capabilities of 500 kW or I MW for use in magnetic fusion experiments. The three designs are at different frequencies: 110 GHz, 140 GHz and 84 GHz. Common features of the three designs include single-anode, magnetron-injection electron guns, internal converters that produce a TEM₀₀ Gaussian output mode and CVD diamond output windows. The three designs use different cavity interaction modes and two of the designs employ collector depression to raise the overall efficiency of the gyrotron installations. Further details of the individual designs and the current status of tests on the various gyrotrons are discussed.