Beam loss detection and mitigation at FRIB

This work presents an overview of beam loss detection and mitigation at the Facility for Rare Isotope Beams (FRIB). A diverse array of loss monitoring systems—including ion chambers, neutron detectors, halo rings, fast thermometry, and differential beam current monitors (BCM)—are deployed to detect losses ranging from large events that risk machine damage to low-level losses that result in undesirable machine activation. To ensure protection, hundreds of detector thresholds with varying time responses are precisely configured for each beam mode, ion species, and energy. The Threshold Configuration Tool (TCT), a sophisticated software solution, optimizes these thresholds to safeguard the machine while minimizing false trips. Additionally, FRIB’s high-power beam employs a novel self-healing liquid lithium film charge stripper, which introduces beam energy fluctuations and occasional gaps in the film, leading to downstream losses. Fast and slow feedback systems stabilize the post-stripper beam energy, effectively reducing these losses. This work will discuss how FRIB experiences running at 10kW beam power influenced the evolution of our systems and tools.