MOP029

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URL	https://doi.org/10.18429/JACoW-NAPAC2025-MOP029
Title	Development and applications of differentiable coherent optical transition radiation simulations
Authors	R. Roussel SLAC National Accelerator Laboratory M. LaBerge The University of Texas at Austin, Helmholtz-Zentrum Dresden-Rossendorf M. Downer The University of Texas at Austin L. Ouyang The University of Texas at Austin, Shanghai Advanced Research Institute, Chinese Academy of Sciences R. Aguilar, F. Wu, A. Irman, J. Kelling, U. Schramm Helmholtz-Zentrum Dresden-Rossendorf
Abstract	Optical transition radiation (OTR) beam profile monitors are widely used to measure the transverse profiles of low-charge electron bunches at advanced linear accelerator facilities such as LCLS-II and FACET-II. However, in scenarios involving strong longitudinal compression or microbunching-induced current spikes, the incoherent OTR signal—proportional to the transverse beam density—is often dominated by coherent OTR (COTR). The resulting COTR patterns exhibit complex dependencies on the full spatiotemporal structure of the beam, rendering conventional profile interpretation ineffective. In this work, we present a novel, backwards-differentiable simulation framework for COTR emission, enabling gradient-based inference of beam characteristics directly from COTR images. We further integrate this framework with the generative phase space reconstruction (GPSR) method to recover high-fidelity 4D transverse phase space distributions of strongly compressed beams. Simulation results demonstrate the ability of this approach to accurately reconstruct detailed beam structure from COTR-based diagnostics, offering a new path toward high-resolution characterization of ultrashort electron bunches.
Paper	download: MOP029.pdf
Cite	BibTeX, LaTeX, Text/Word, RIS, EndNote
Conference	6th North American Particle Accel. Conf. (NAPAC2025)
Series
Location	Sacramento, CA, USA
Date	10-15 Aug 2025
Publisher	JACoW Publishing, Geneva, Switzerland
Editorial Board	Tor O. Raubenheimer (SLAC), Roark A. Marsh (LLNL), Eric Prebys (UC Davis), Ling Wang (MSU), Petr M. Anisimov (LANL), Kip Bishofberger (LANL), Gustavo Bruno (ANL), Zhichu Chen (SARI), Jan Chrin (PSI), Kelly Jaje (ANL), Jaeyu Lee (POSTECH), Magdalena Montes-Loera (SLAC), Mary Saethre (PHENOTYPE), Tasha Summers (SLAC), Kent Wootton (ANL)
Online ISBN	978-3-95450-261-5
Online ISSN	2673-7000
Received	08 August 2025
Revised	13 August 2025
Accepted	14 August 2025
Issued	28 January 2026
DOI	10.18429/JACoW-NAPAC2025-MOP029
Pages	110-112
Copyright	Published by JACoW Publishing under the terms of the Creative Commons Attribution 4.0 license. Any further distribution of this work must maintain attribution to the author(s), the published article's title, publisher, and DOI.