Concepts for beam diagnostics based on planar pickups on a printed circuit board

For the upgrade of the electro-optical bunch arrival-time monitors (EO-BAMs) employed at several free-electron laser (FEL) facilities, a novel pickup structure has been proposed. Its feasibility was successfully tested at the ELBE accelerator. The design comprises planar pickups on a printed circuit board (PCB) with an integrated combination network. It delivers a significantly stronger signal compared to established pickups. Applying the upgrade to existing machines enables two key capabilities: Reliable operation at 1 pC charge levels for FELs and ultrafast electron diffraction facilities, and enhanced arrival-time resolution for standard operational modes. Furthermore, the PCB implementation enables unprecedented flexibility in planar pickup design, facilitating multi-functional diagnostic capabilities. This work presents a compact implementation strategy for integrating high- and low-resolution channels for EO-BAMs on a single substrate through a dual-functionality layout, and conceptual advancements in beam diagnostics using a PCB architecture for measuring other beam properties.