%0 Journal Article
%A Trebushinin, Andrei
%A Serkez, Svitozar
%A Freund, Wolfgang
%A Perosa, Giovanni
%A Koch, Andreas
%A Gruenert, Jan
%A Geloni, Gianluca
%A Qin, Weilun
%A Tomin, Sergey
%T Noninterferometric method for transverse electron beam size diagnostic with synchrotron radiation at a free-electron laser
%J Physical review accelerators and beams
%V 28
%N 11
%@ 2469-9888
%C College Park, MD
%I American Physical Society
%M PUBDB-2025-05674
%P 112801
%D 2025
%X 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.
%F PUB:(DE-HGF)16
%9 Journal Article
%R 10.1103/31gl-qyk7
%U https://bib-pubdb1.desy.de/record/642868