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Electron Cloud Meeting #87
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Europe/Zurich
6/R-018 (CERN)
Electron Cloud Meeting
Participants: H. Bartosik, E. De La Fuente Garcia, L. Giacomel, F. Groenvold, M. Himmerlich, I. Mases Sole, L. Mether, K. Li, K. Paraschou, G. Rumolo, C. Zannini
Lotta presents the plans for the scrubbing run, based on presentations and discussions at the SPS MPC over the past few weeks.
Discussion:
Ideas for measurements that could be done during the scrubbing are discussed. Giovanni proposes tail studies by the team of Hannes & co. Elena is interested in making live chromaticity measurements.
The monitoring of the wire scanners during scrubbing is discussed. Carlo and Elena confirm that their experience suggests negative peaks in the signals are a sign of concern to look out for and inform SY-BI of.
The “fast valves” around water-cooled septa are discussed. In the SPS MPC #55, Anthony Harrison (TE-VSC) mentioned that the fast valves have been blocked open also in operation for the past few years and that their removal from the machine is being considered. It is agreed that the impact on scrubbing/operation of closing the valves could be tested towards the end of the scrubbing run. It is also proposed to revisit the topic of their usage and plans for removal at an upcoming SPS MPC.
The vacuum interlock thresholds for the kickers are discussed. Kevin confirms that the implemented SIS interlock thresholds are 2e-7 for all MKPs and 6e-7 for the MKDHs (identical to the hardware interlock threshold).
Marcel confirms that interventions took place on the e-cloud monitors during the YETS. Three liners were exchanged, as listed below, and dead channels were fixed:
- BESCLD-VECM11732: Cu-LIPSS (fresh)
- BESCLD-VECM11754: StSt (fresh)
- BESCLD-VECM11737: Cu, for reference (fresh)
- BESCLD-VECM11738: CNe13 (in since 2008)
Hannes recalls the issues that occurred with the ZS during scrubbing in 2023. It appears that the setting up of the slow extraction in parallel with high intensity scrubbing was the root cause of the problem. It is decided to pause scrubbing during the setting up of the slow extraction, scheduled for Monday 11.3, to avoid similar issues this year. Pausing scrubbing at this point will also be benefit MKP-S cooling, in advance of the test with shifted orbit that is scheduled to take place during the night. The time can instead be dedicated to setting up the long flat top acceleration cycle with INDIVS and other low-intensity activities. It remains to be decided if a scrubbing pause is needed also for ZS alignment at a later stage.
The intensity limits for wire scanner measurements at FB and FT should be recalled.
It is decided that daily scrubbing summaries will be made on Mattermost and in the SPS (MD?) Logbook, and scrubbing meetings will take place on Zoom every morning, at least during the first days of scrubbing.
Action: Compile list of parasitic/related studies along with a tentative schedule (Lotta, Kevin)
Action: Verify intensity limits for wire scanner measurements at FB and FT (Lotta/Carlo/Kevin)
Action: Organise scrubbing Zoom meetings (Lotta)
Action: Update scrubbing CodiMD for 2024 (Lotta)
Action: Propose dedicated studies to be done by operators during Easter weekend (everybody, Lotta, Kevin)
Action: Organise presentation/discussion (at SPS MPC) on fast valves with TE-VSC (Kevin, Lotta)
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