The ESS Fast Beam Interlock System: First Experience of Operating With Proton Beam

The European Spallation Source (ESS), Sweden, currently in its early operation phase, aims to be the most powerful neutron source in the world. Proton beam pulses are accelerated and sent to a rotating tungsten target, where neutrons are generated via the spallation effect. The damage potential of the ESS proton beam is high and melting of copper or steel can happen within less than 5 microseconds. Therefore, highly reliable and fast machine protection (MP) systems have been designed and deployed. The core system of ESS Machine Protection is the Fast Beam Interlock System (FBIS), based on FPGA technology. FBIS collects data from all relevant accelerator and target systems through 300 direct inputs and decides whether beam operation can start or must stop. The architecture is based on two main building blocks: Decision Logic Node (DLN), executing the protection logic and realizing interfaces to Higher-Level Safety, Timing System and EPICS Control System. The second block, the Signal Condition Unit (SCU), implements the interface between FBIS inputs/outputs and DLNs. This paper gives an overview on FBIS and a summary on its performance during beam commissioning phases since 2021.
Proceedings of the 31st International Linear Accelerator Conference, LINAC2022, Liverpool, UK