Abstract
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.
Funder
Commonwealth Scientific and Industrial Research Organisation
La Trobe University
Publisher
International Union of Crystallography (IUCr)
Subject
Condensed Matter Physics,General Materials Science,Biochemistry,General Chemistry
Reference85 articles.
1. X-ray laser–induced electron dynamics observed by femtosecond diffraction from nanocrystals of Buckminsterfullerene
2. Agapov, I. & Geloni, G. A. (2013). Proceedings of IPAC2013, 12-17 Mar 2013, Shanghai, China, pp. 1173-1175.
3. Agapov, I., Geloni, G., Feng, G., Kocharyan, V., Saldin, E., Serkez, S. & Zagorodnov, I. (2014). arXiv:1404.1177.
4. Design of the mirror optical systems for coherent diffractive imaging at the SPB/SFX instrument of the European XFEL
5. Perspectives on single particle imaging with x rays at the advent of high repetition rate x-ray free electron laser sources