Journal Article

PUBDB-2025-05674

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Noninterferometric method for transverse electron beam size diagnostic with synchrotron radiation at a free-electron laser

Trebushinin, A. (Corresponding author)Extern*XFEL.EU* ; Serkez, S.XFEL.EU* ; Freund, W.XFEL.EU* ; Perosa, G.Extern*XFEL.EU* ; Koch, A.Extern*XFEL.EU* ; Gruenert, J.XFEL.EU* ; Geloni, G.XFEL.EU* ; Qin, W.DESY* ; Tomin, S.DESY*

2025
American Physical Society College Park, MD

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Please use a persistent id in citations: doi:10.1103/31gl-qyk7

Abstract: We present a noninterferometric method for measuring the transverse electron beam size at the European XFEL based on synchrotron radiation intensity autocorrelation. The technique enables cell-by-cell diagnostics along the SASE1 undulator using existing hardware: a commissioning monochromator and a spatial x-ray detector. We extend the results of [A. Trebushinin et al., companion paper, First observation of synchrotron radiation spikes for transverse electron beam size measurements at a free-electron laser, Phys. Rev. Lett. 135, 215001 (2025).] focusing on data analysis procedures and technical implementation. Our method allows for extraction of the beam size from noisy measured intensity distributions with a signal-to-noise ratio as low as 0.9 and is capable of distinguishing between the projected and slice sizes. To validate our approach, we introduced a mismatch in the magnetic lattice, inducing a controlled sinusoidal variation in the beam size along the undulator. The corresponding modulation was clearly reproduced in the electron beam size values extracted from the autocorrelation measurements. This method offers a practical solution for transverse electron beam size diagnostics in high-energy linacs, with direct application to the operation and tuning of free-electron laser facilities.

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Contributing Institute(s):

1. Koordination des XFEL-Beschleunigers (MXL)
2. FEL Physics (XFEL_E2_FP)
3. X-Ray Photon Diagnostics (XFEL_DO_ID_XPD)

Research Program(s):

1. 621 - Accelerator Research and Development (POF4-621) (POF4-621)
2. 6G13 - Accelerator of European XFEL (POF4-6G13) (POF4-6G13)

Experiment(s):

1. Experiments at XFEL

Appears in the scientific report 2025

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Database coverage:
; ; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; DOAJ Seal ; Essential Science Indicators ; IF < 5 ; JCR ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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