The SA3 FEL imager is now protected via the Big Brother server, which creates a beam limit on the bunch pattern server if necessary.
contact Andreas Koch, Lars Fröhlich for more details or consult the imager manual, section 2.9:
https://docs.xfel.eu/share/page/site/xfelwp74/document-details?nodeRef=workspace://SpacesStore/1766b430-7c48-4c46-bb2d-1774d69e1246
demonstration 27.1.2025 to Jan Grünert, Harald Sinn, Andreas Galler.
Function: The Big Brother limits the number of pulses in SA3 via a beam limit in case of danger, individually for each screen of the FEL imager, AND only if an imager screen is inserted. The EPS is valid as before.
This means that if the EPS interlock for the FEL imager is enabled (default setting, 2 pulses maximum), the intervention by the Big Brother could reduce pulses to 1 or 0.
The potential limit of the number of pulses for each screen is shown in the FEL imager scene, as before.
Best practice: Use the GATT to limit the pulse energy. Avoid to operate with a strongly saturated image. Use low absorbing ND filters.
eLogs posts to: eLog Operation-2025, Zulip SASE3_INSTRUMENT_COMMISSIONING, ttfinfo |