Single-shot electron bunch profile monitor based on coherent transition radiation imaging

The development of longitudinal diagnostics for short-pulse electron accelerators is challenging but necessary to provide high-brightness electron bunches. This is equally true in novel plasma accelerators and for free electron lasers. The gold standard for such measurements is the transverse deflecting cavity (TDC); however, these devices are typically invasive and costly to produce and operate. As an alternative, a THz-based reflective imaging system has been designed and installed at the MAX IV short pulse facility (SPF) for imaging coherent transition radiation (CTR) for bunch profile reconstruction. This contribution presents the progress towards applying transfer learning to deep learning models for evaluating the reconstruction of bunch profiles from experimentally acquired CTR images, building on previous successes in profile prediction using simulated data. Practical resolution limits and the next steps in the development of the monitor are also discussed, where the reconstructions of the longitudinal profile will be achieved using single-shot CTR images and benchmarked against the TDC bunch profiles.