Novel Coating for Suppression of Multipactor in High Power Microwave Devices

Multipactor is an incessant problem that plagues numerous commercial and military systems, including satellites and particle accelerator components such as klystrons and free electron lasers FELs). Metallic surfaces within High Power Microwave HPM) devices are susceptible multipactor due to the high Secondary Electron Emission SEE) coefficient of internal surfaces. Current solutions, including traditional coatings such as Titanium Nitride TiN) or use of magnetic systems to suppress SEE, are insufficient to support HPM operations at high frequencies 1 40GHz) and high operating powers. Nokomis has developed a unique thin film material with an extremely low SEE that does not affect the performance of Radio Frequency RF) devices. The material, an amorphous carbon nanocoating, has been successfully demonstrated to have superior multipactor mitigation performance to conventional solutions up to 2.8GHz and 12MW. In this Phase I effort, Nokomis will enhance the developed coating material, expanding its range for multipactor mitigation to 40GHz to support HPM applications such as FELs, klystrons, and photocathodes. Material microstructure and bonding hybridization will be optimized for high frequency applications in addition to improvements to coating manufacture and integration. Nokomis will perform high frequency testing using its established on-site facilities or in coordination with those of a national laboratory such as Argonne. Test results will demonstrate the feasibility of using the proposed technology to mitigate or eliminate multipactor in HPM devices. Successful execution of the proposed effort will further optimize this coating for applicability to HPM devices operating at high frequencies. Adoption of the developed technology will prevent catastrophic loss of equipment, increase the reliability of HPM devices, increase the power specifications for HPM devices to enable enhanced operations, and reduce component lifetime costs. The success of this effort will address performance limiting problems currently experienced in equipment used for multiple fields, including communications, manufacturing, radar, medical diagnostics and radiotherapy.