Electrical and thermo-mechanical analysis of beam recovery system for megawatt power gyrotron

• Electrical design of single stage depressed collector for high power gyrotron tube.
• Efficiency enhancement by collecting spent beam.
• Optimization of geometry and magnetic field for optimized beam spread.
• Optimization of cooling duct system for better thermal management.

The paper presents the electrical and thermo-mechanical design of single stage beam recovery system for 120 GHz, 1 MW gyrotron. The electrical study shows that the cylindrical shape single stage beam recovery system enhances the efficiency by 66.26%. The maximum power deposited to collector in depressed collector operation is 0.48 MW for electronic efficiency, 30% and 1.44 MW for DC electron beam. The thermo-mechanical analysis has been performed to evaluate the water cooling system. The cooling system has capability of accommodating a peak wall loading, 0.9 kW/cm2 at flow rate of 1500 l/min for safe operating time, 60 ms. Further, a high voltage analysis is also carried out to appraise the electric field distribution in the collector.