Design collector for high average-power/CW gyro-devices (1) - methods of raising dissipated power density

There are two key issues to improve the collector dissipated power capacity: 1 ) Improving the dissipated power density; 2 ) Increasing effective collection area and collection uniformity. In this paper, the threshold factors of the dissipated power density determine are studied firstly, then the method about how to improve the dissipated power density under the condition of the stable working would be propose. Using this method the dissipated power density is increased to 1.65kw/cm
²
while the tube works stably. By employing the electron collection smooth method (discuss in following papers), a total 200 kW dissipated power can be stably collected in a compact longitudinal collector. This collector is successfully applied in the Q-band high-average and continuous-wave gyrotron traveling wave tube to ensure a 10hours non-stop stable operation.