Single-shot third-harmonic spectral diagnostics for tender X-ray FEL pulses using a bent-crystal spectrometer

Arrell, C.; Lemke, H.; Prat, E.

doi:10.1107/S1600577526006739

Figure 2
(a) Single-shot spectra of the third harmonic recorded with the bent-crystal spectrometer. The shaded band shows the 16%–84% range of 30 single shots and the thin blue curve shows a representative selected shot. The red curve is the average spectrum of the selected shots, and the black dashed line is a Gaussian fit to this average. The fit yields a relative energy spread of ΔE/E ≃ 3.1‰ for the fundamental at 2.5 keV. The horizontal axis is the measured third-harmonic photon energy divided by three, corresponding to the fundamental photon energy. (b) Residual of the average spectrum with respect to the Gaussian fit, highlighting the non-Gaussian low-energy tail.

JOURNAL OF
SYNCHROTRON
RADIATION

ISSN: 1600-5775

Volume 33| Part 5| September 2026|

https://doi.org/10.1107/S1600577526006739

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