Speaker
Description
Ultrafast electron diffraction (UED) is a powerful tool for probing transient structural dynamics, however, its temporal resolution is fundamentally limited by laser-electron beam time of arrival jitter. To address the need for sub-10 femtosecond precision, we utilized a 4.76 GHz two-cell cavity-based Beam Arrival Monitor (BAM) designed to achieve high sensitivity at extremely low bunch charges. We report experimental results from the UCLA PEGASUS beamline, where time of arrival beam tests demonstrated strong sensitivity to beam-induced RF signals. Crucially, the cavity phase serves as a high-fidelity timing observable. While we demonstrate exceptional charge sensitivity capable of measuring bunch charges below 0.5 fC, the optimal timing sensitivity required for precision synchronization is obtained at higher bunch charges. Building on these findings, ongoing work integrates the BAM with a state-of-the-art RFSoC digital Low-Level RF (LLRF) platform. By combining a multi-core ARM processor, FPGA, and high-speed ADCs and DACs on a single chip, this architecture significantly extends diagnostic capabilities, enabling multichannel processing, low-latency deterministic feedback and AI/ML real-time control. This framework lays the foundation for deploying physics-informed machine learning models to suppress noise and correct drift beyond conventional hardware limits, paving the way for robust sub-10 fs synchronization in next-generation UED experiments.
Funding Agency
DOE Office of Science BES and HEP
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