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A phenomenological model of the X-ray pulse statistics of a high-repetition-rate X-ray free-electron laser

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posted on 2023-10-18, 03:50 authored by Trey GuestTrey Guest, Richard Bean, Raimund Kammering, Grant van RiessenGrant van Riessen, Adrian MancusoAdrian Mancuso, Brian AbbeyBrian Abbey
Many coherent imaging applications that utilize ultrafast X-ray free-electron laser (XFEL) radiation pulses are highly sensitive to fluctuations in the shot-to-shot statistical properties of the source. Understanding and modelling these fluctuations are key to successful experiment planning and necessary to maximize the potential of XFEL facilities. Current models of XFEL radiation and their shot-to-shot statistics are based on theoretical descriptions of the source and are limited in their ability to capture the shot-to-shot intensity fluctuations observed experimentally. The lack of accurate temporal statistics in simulations that utilize these models is a significant barrier to optimizing and interpreting data from XFEL coherent diffraction experiments. Presented here is a phenomenological model of XFEL radiation that is capable of capturing the shot-to-shot statistics observed experimentally using a simple time-dependent approximation of the pulse wavefront. The model is applied to reproduce non-stationary shot-to-shot intensity fluctuations observed at the European XFEL, whilst accurately representing the single-shot properties predicted by FEL theory. Compared with previous models, this approach provides a simple, robust and computationally inexpensive method of generating statistical representations of XFEL radiation.


Trey Guest acknowledges support from the Commonwealth Scientific and Industrial Research Organization (CSIRO) Alumni. Brian Abbey acknowledges support from the La Trobe Biomedical and Environmental Sensor Technology (BEST) Research Centre. This work has been enabled by megahertz imaging technology developed within internal RD MHz Microscopy and EIC-Pathfinder MHz Tomoscopy (GA 101046448) projects.


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International Union of Crystallography



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© The Authors 2023 This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.