The application of fluorescent crystal media in wide-range X-ray detectors provides an opportunity to directly image the spatial distribution of ultra-intense X-ray beams including investigation of the focal spot of free-electron lasers. Here the capabilities of the micro- and nano-focusing X-ray refractive optics available at the High Energy Density instrument of the European XFEL are reported, as measured in situ by means of a LiF fluorescent detector placed into and around the beam caustic. The intensity distribution of the beam focused down to several hundred nanometers was imaged at 9 keV photon energy. A deviation from the parabolic surface in a stack of nanofocusing Be compound refractive lenses (CRLs) was found to affect the resulting intensity distribution within the beam. Comparison of experimental patterns in the far field with patterns calculated for different CRL lens imperfections allowed the overall inhomogeneity in the CRL stack to be estimated. The precise determination of the focal spot size and shape on a sub-micrometer level is essential for a number of high energy density studies requiring either a pin-size backlighting spot or extreme intensities for X-ray heating.

Makarov, S., Makita, M., Nakatsutsumi, M., Pikuz, T., Ozaki, N., Preston, T., et al. (2023). Direct LiF imaging diagnostics on refractive X-ray focusing at the EuXFEL High Energy Density instrument. JOURNAL OF SYNCHROTRON RADIATION, 30(1 (January 2023)), 208-216 [10.1107/S1600577522006245].

Direct LiF imaging diagnostics on refractive X-ray focusing at the EuXFEL High Energy Density instrument

Cerantola, Valerio;
2023

Abstract

The application of fluorescent crystal media in wide-range X-ray detectors provides an opportunity to directly image the spatial distribution of ultra-intense X-ray beams including investigation of the focal spot of free-electron lasers. Here the capabilities of the micro- and nano-focusing X-ray refractive optics available at the High Energy Density instrument of the European XFEL are reported, as measured in situ by means of a LiF fluorescent detector placed into and around the beam caustic. The intensity distribution of the beam focused down to several hundred nanometers was imaged at 9 keV photon energy. A deviation from the parabolic surface in a stack of nanofocusing Be compound refractive lenses (CRLs) was found to affect the resulting intensity distribution within the beam. Comparison of experimental patterns in the far field with patterns calculated for different CRL lens imperfections allowed the overall inhomogeneity in the CRL stack to be estimated. The precise determination of the focal spot size and shape on a sub-micrometer level is essential for a number of high energy density studies requiring either a pin-size backlighting spot or extreme intensities for X-ray heating.
Articolo in rivista - Articolo scientifico
compound refractive lenses; focusing system; lithium fluoride (LiF) detector; X-ray beam characterization; X-ray focusing; X-ray free-electron lasers;
English
2023
30
1 (January 2023)
208
216
open
Makarov, S., Makita, M., Nakatsutsumi, M., Pikuz, T., Ozaki, N., Preston, T., et al. (2023). Direct LiF imaging diagnostics on refractive X-ray focusing at the EuXFEL High Energy Density instrument. JOURNAL OF SYNCHROTRON RADIATION, 30(1 (January 2023)), 208-216 [10.1107/S1600577522006245].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/399195
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