Group Selection Page HELP DOC Controls Group Data Analysis Group ITDM WP76 DET Vacuum EEE WP78 WP74 FXE SCS SPB MID HED SQS SXP Sample Environment Operation PSPO XO TS Migrated2Zulip
OPERATION-2025 OPERATION-2024 OPERATION-2023 OPERATION-2022 OPERATION-2021 OPERATION-2020 OPERATION-2019 SASE1-2018 SASE1-2017 Experiment data
  OPERATION-2025 logbook, Contact: F.Wolff-Fabris, A.Galler, H.Sinn  Not logged in ELOG logo
Message ID: 3     Entry time: 29 Jan 2025, 09:08
Author: Andreas Koch 
Group: XPD 
Subject: SA3 status 

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

ELOG V3.1.4-7c3fd00