Development and test of a compact RF coupler utilizing additive manufacturing

Abstract Additive manufacturing has proven to be a powerful technique for rapid prototyping and the fabrication of complex geometries. For use in a 433 MHz IH-DTL cavity, a CF40 coupler was developed and manufactured from high-purity copper by laser powder bed fusion. In this process, metal powder is applied layer by layer and fused with a laser to the existing structure, allowing a water-cooling concept that would be impossible to implement using conventional manufacturing methods. The coupler features a ceramic window water cooled on both sides, an outer conductor with spiral cooling channels, and a water cooled inner conductor. Optimal power transmission is frequency-dependent and is fine-tuned by adjusting the inner conductor geometry through CST simulations. Initial tests of the coupler were carried out during conditioning the Frankfurt Neutron Source IH-DTL at power levels of up to 12 kW continuous wave.