Improved Collectors for High Power Gyrotrons

Collectors for high power gyrotrons, needed for fusion devices, are not sufficiently robust, resulting in recent failures of U.S.-produced gyrotrons. These failures are causing serious problems for manufacturers and users, and could jeapodize the U.S. gyrotron industry. This project will develop technology to reduce the thermal power density and stresses leading to failures. The approach will investigate modifications to the electrical, mechanical, beam optics, and thermal design, and also will explore new materials and assembly procedures. In Phase I, charged particle codes will be used to explore alternative geometries that improve the spent beam distribution in collectors. Techniques will be explored to reduce and trap backscattered electrons, thereby increasing the potential depression and reducing the power densities. The utilization of refractory materials, capable of dissipating higher heat loads than the copper now used, also will be explored. Commercial Applications and Other Benefits as described by the awardee: The technology should improve the performance of gyrotron collectors and increase their ability to dissipate high thermal loads without failure, enabling the development of higher power gyrotrons for fusion and defense applications.