23–28 Aug 2026
America/Los_Angeles timezone

Absolute characterization of sub-femtosecond electron bunches in SwissFEL using a Bunch-Compressor-Monitor

THY02
27 Aug 2026, 11:00
30m
Invited Oral Presentation Session 10: Electron Diagnostics, Timing, Synchronization, and Controls Electron Diagnostics, Timing, Synchronization, and Controls (Invited)

Speaker

Gian Luca Orlandi (Paul Scherrer Institute)

Description

Monitoring the electron pulse duration is crucial for setting up and stabilizing the lasing in a linac-driven Free-Electron-Laser (FEL). Bunch-Compressor-Monitors (BCMs) allow for a non-invasive - albeit uncalibrated – monitoring of the electron pulse duration at the exit of a magnetic chicane by detecting and fully integrating the radiation energy emitted by the electron beam around the spectral threshold of the temporal coherence. We will present results of the experimental characterization of low-charge and sub-femtosecond electron bunches generated in SwissFEL during a SASE-lasing with a single-spike mode prevalence in the frequency domain (*). The electron pulse duration measurements were performed by applying a formal processing method (**) of the signal readouts of a BCM which is equipped with two independent and simultaneously illuminated detectors covering two partially overlapping wavelength bands. In a CW superconducting linac-driven FEL, where the non-invasiveness is a mandatory feature for the beam diagnostics, the implementation of the “BCM two-detector method” discloses the path to the use of a BCM as an absolute monitor of the electron pulse duration.

Footnotes

(*) Prat, et al, S. Enhanced generation of single-spike hard x-ray free-electron laser pulses with lower charge and shorter electron beams in the injector. Phys. Rev. Res. 7, 4, L042060 (2025). https://link.aps.org/doi/10.1103/t8qq-h31p

(**) Orlandi, G.L. Absolute and non-invasive determination of the electron bunch length in a free electron laser using a bunch compressor monitor. Sci Rep 14, 6319 (2024). https://doi.org/10.1038/s41598-024-5658

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Author

Gian Luca Orlandi (Paul Scherrer Institute)

Co-authors

Mr Arturo Alarcon (Paul Scherrer Institute) Christoph Kittel (Paul Scherrer Institute) Didier Voulot (Paul Scherrer Institute) Eduard Prat (Paul Scherrer Institute) Dr Francesca Addesa (Paul Scherrer Institute) Mr Helge Brands (Paul Scherrer Institute) Mr Kurt Bitterli (Paul Scherrer Institute) Nicole Hiller (Paul Scherrer Institute) Dr Philipp Dijkstal (Paul Scherrer Institute) Rasmus Ischebeck (Paul Scherrer Institute) Sven Reiche (Paul Scherrer Institute) Thomas Schietinger (Paul Scherrer Institute) Dr Tobias Weilbach (Paul Scherrer Institute)

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