| By shaping a set of metal mirrors, the output from a launcher in a gyrotron can be changed into a rather good Gaussian beam. A high efficiency mirror system will transform nearly all of the power out of the launcher into an output beam having a high coupling coefficient to the desired target Gaussian beam. This is highly desirable because more useable power can be produced and less power will be lost inside the gyrotron tube.; This investigation includes many parts. First, we investigate the iterative algorithm for designing ideal phase correctors for simple beam transformations. Second, an actual mirror system using two mirrors as shaping mirrors is designed and tested for a new launcher. Excellent experimental results are obtained. Third, we developed two mirror systems using three shaping mirrors for a single-frequency gyrotron. The simulation results are very good. Finally, we designed mirror systems using three shaping mirrors for a possible step-tunable gyrotron. An improved method (the field intensity weighting scheme) for finding the perturbations to the mirror surfaces in the procedure of mirror shaping is proposed and very good design results are obtained. |
