RF Characterization and Beam Measurements with Additively Manufactured Fast Faraday Cups

The early stages of most particle accelerator chains produce sub-ns bunches with velocities in the range of 1% to 20% of the speed of light. Fast Faraday Cups (FFCs) are designed to measure the longitudinal charge distribution of these short bunches of free charges. Coaxial designs have been utilized at the GSI Helmholtz Centre for Heavy Ion Research (GSI)’s linear accelerator UNILAC to characterize ion bunches with bunch lengths ranging from a few hundred ps to a few ns. The typical design goals are to avoid the pre-field of the charges and to suppress secondary electron emission (SEE) while preserving the capability of bunch-by-bunch measurements. This contribution presents a novel FFC design manufactured using additive manufacturing, e.g., laser powder bed fusion (LPBF), and compares it with a traditionally produced FFC. The article highlights the design process, RF characterization, and selected measurements with ion beam carried out at GSI.