Model-free pattern separation of two-color ultrafast X-ray diffraction
Abstract
Two-color X-ray imaging with Free Electron Laser pulses offers a powerful approach for probing ultrafast structural dynamics in nanoscale systems, combining (near-)atomic spatial resolution with femtosecond temporal precision. The first X-ray pulse captures the object's initial state, while the second, time-delayed pulse records its subsequent evolution. A key challenge lies in disentangling the two patterns simultaneously recorded by the same detector. We demonstrate the realization of this approach on structurally varying nanoscale particles using two X-ray pulses of different photon energies, 1 and 1.2 keV. Sub-micrometer helium nanodroplets generated in vacuum are irradiated by the two X-ray pulses separated in time by up to 750 femtoseconds. Taking advantage of the high photon-energy resolution of the imaging detector, we separate the overlapping diffraction signals by analyzing individual pixel counts and applying pattern recognition. The helium nanodroplets' spherical shape allows us to cross-validate this approach by fitting the radial scattering profiles with Mie solutions for abichromatic field. The excellent agreement between the two methods, particularly in the sparsely illuminated outer regions of the diffraction patterns where high-resolution structural information is encoded, highlights the quality of this approach and its potential for future advanced X-ray movie techniques.
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BibTeX
@article{hecht2026modelfree,
title = {{Model-free pattern separation of two-color ultrafast X-ray diffraction}},
author = {Linos Hecht and Yevheniy Ovcharenko and Asbjørn Ø. Lægdsmand and Björn Bastian and Thomas Baumann and Alessandro Colombo and Subhendu De and Alberto de Fanis and Simon Dold and Thomas Fennel and Robert Hartmann and Katharina Kolatzki and Sivarama Krishnan and Björn Kruse and Aaron Laforge and Bruno Langbehn and Suddhasattwa Mandal and Tommaso Mazza and Cristian Medina and Christian Peltz and Thomas Pfeifer and Björn Senfftleben and Keshav Sishodia and Frank Stienkemeier and Rico Mayro P. Tanyag and Paul Tümmler and Sergey Usenko and Andreas Heidenreich and Michael Meyer and Daniela Rupp and Marcel Mudrich},
journal = {Nature Communications},
year = {2026},
month = sep,
doi = {10.1038/s41467-026-77085-z},
url = {https://hal.science/hal-05795879v1},
note = {CC BY},
}
RIS
TY - JOUR
TI - Model-free pattern separation of two-color ultrafast X-ray diffraction
AU - Linos Hecht
AU - Yevheniy Ovcharenko
AU - Asbjørn Ø. Lægdsmand
AU - Björn Bastian
AU - Thomas Baumann
AU - Alessandro Colombo
AU - Subhendu De
AU - Alberto de Fanis
AU - Simon Dold
AU - Thomas Fennel
AU - Robert Hartmann
AU - Katharina Kolatzki
AU - Sivarama Krishnan
AU - Björn Kruse
AU - Aaron Laforge
AU - Bruno Langbehn
AU - Suddhasattwa Mandal
AU - Tommaso Mazza
AU - Cristian Medina
AU - Christian Peltz
AU - Thomas Pfeifer
AU - Björn Senfftleben
AU - Keshav Sishodia
AU - Frank Stienkemeier
AU - Rico Mayro P. Tanyag
AU - Paul Tümmler
AU - Sergey Usenko
AU - Andreas Heidenreich
AU - Michael Meyer
AU - Daniela Rupp
AU - Marcel Mudrich
PY - 2026
DA - 2026/09/03
JO - Nature Communications
DO - 10.1038/s41467-026-77085-z
UR - https://hal.science/hal-05795879v1
AB - Two-color X-ray imaging with Free Electron Laser pulses offers a powerful approach for probing ultrafast structural dynamics in nanoscale systems, combining (near-)atomic spatial resolution with femtosecond temporal precision. The first X-ray pulse captures the object's initial state, while the second, time-delayed pulse records its subsequent evolution. A key challenge lies in disentangling the two patterns simultaneously recorded by the same detector. We demonstrate the realization of this approach on structurally varying nanoscale particles using two X-ray pulses of different photon energies, 1 and 1.2 keV. Sub-micrometer helium nanodroplets generated in vacuum are irradiated by the two X-ray pulses separated in time by up to 750 femtoseconds. Taking advantage of the high photon-energy resolution of the imaging detector, we separate the overlapping diffraction signals by analyzing individual pixel counts and applying pattern recognition. The helium nanodroplets' spherical shape allows us to cross-validate this approach by fitting the radial scattering profiles with Mie solutions for abichromatic field. The excellent agreement between the two methods, particularly in the sparsely illuminated outer regions of the diffraction patterns where high-resolution structural information is encoded, highlights the quality of this approach and its potential for future advanced X-ray movie techniques.
SN - 2041-1723
SN - 2041-1723
ER -