First Single-Shot SASE spectra of SwissFEL successfully measured

The team of the Laboratory for Advanced Photonics (LAP) has succeeded to perform the first set of shot-to-shot measurements of the SwissFEL generated spectrum. The measurements were done with a 10 micrometer thin Si (111) bent crystal at the photon energy of 5.82 keV, using the third harmonic of 1.94 keV of SwissFEL. As SwissFEL is working based on the principle of Self-Amplified Spontaneous Emission (SASE), it requires monitoring of the photon spectral distribution at a repetition rate of 100 Hz for machine optimization and online diagnostics for the experiments and operators. The Photon Single Shot Spectrometer has been designed for the photon energy range of 4-12 keV provided by the Aramis beamline. It is capable of measuring the spectrum in a non-destructive manner, with an energy resolution of ΔE/E = (2–5) x 10^-5 over an energy bandwidth of 0.5% on a shot-to-shot basis. The full design and principle are described and can be found in below-mentioned publication.