Development of MHz X-ray full-field imaging at European XFEL

The X-ray full-field imaging performed in a pulse-resolved manner opens new possibilities for visualizing matter in motion. Large-scale X-ray facilities, such as synchrotrons (e.g., ESRF, APS, Spring-8) and XFEL sources, deliver ultra-short pulses (~200 ps to ~20 fs) at megahertz repetition rates. The latest generation of X-ray sources offers three orders of magnitude more photons per pulse compared to previous generations. This exceptional performance, combined with MHz repetition rates, enables unique opportunities to study fast stochastic phenomena, with object velocities reaching ~km/s. Recently, we proposed and demonstrated X-ray microscopy in the phase contrast regime, sampled at MHz rates [1], and developed dedicated instrumentation that is accessible to broad user communities [2] through user proposals at the EuXFEL. However, the limitations of 2D projection imaging constrain a comprehensive understanding of dynamic systems. Processes such as cavity formation and collapse, shockwave emission during cavity annihilation, and other phenomena require 3D temporal information (4D imaging) for a complete analysis. To address this challenge, we have introduced a novel X-ray optical scheme [3] and developed a MHz tomoscopy prototype. This innovative system enables up to six angular projections for each individual X-ray pulse using crystal splitters, providing an advanced framework for 4D imaging of dynamic phenomena [4] . I will present recent state of the art development and discuss further prospects and possibilities for MHz X-ray microscopy
References
[1] Vagovič, P.; et al. Megahertz X-ray microscopy at X-ray Free-Electron Laser and Synchrotron sources Optica, 2019, 1106-1109 ,
[2] Koliyadu, Jayanath and Vagovič, Patrik et al. Development of MHz X-ray phase contrast imaging at the European XFEL, 2025-01 Journal of Synchrotron Radiation , Vol. 32, No. 1 p. 17-28
[3] Vagovic Patrik, Bellucci Valerio, Villanueva-Perez Pablo, Yashiro Wataru, Multi beam splitting and redirecting apparatus for a tomoscopic inspection, tomoscopic inspection apparatus and method for creating a three dimensional tomoscopic image of a sample 2023 Global patent index EP4160623A1
[4] HORIZON-EIC-2021-PATHFINDEROPEN-01-01, Grant agreement: 101046448, https://tomoscopy.eu