CERN Accelerating science

Pre-discussion on 27-JAN-2021:

MP aspects of Slow Extraction – Brainstorming, 27/01/2021

Present: Cedric, Christoph, Francesco, Jan, Verena

Findings and discussion:

• For the given interlocking, the extraction bumpers are the most critical component for Slow Extraction (SE). The sextupoles are less critical.
• All maskable interlocks to the BIS in LSS2 are already in use. Therefore, the FGC state input of the bumpers cannot be directly connected to the BIS (unless installing new HW).
• The bumper magnets are connected to the WIC. If their PC state is FAULT OFF, the WIC interlocks and the beam is cut via the BIS.
• The bumper currents have a fixed threshold (not a threshold that can follow a function).
• The bumpers are connected to the Ring BIS. Therefore, it is not possible to interlock on a window (they are only switched on just before the SE).
• A SW interlock of the bumper state is already in place.
• New BLM RS and new dI/dt can be used for SW interlocking and add protection functionality for the SE in Run3.
• Jan: the interlocking strategy of the North Area (NA) has to be reviewed. BIS for NA and transferline are to be installed in LS3/LS4.
• Not all locations in TT20 are covered by BLMs. Jan: One should add more BLMs where required in the framework of the NA consolidation.
• Conclusion: No short-term interlocking solution seems feasible. Instead, a more complete concept should be developed, also considering the consolidation work for the NA.
• Actions:
  • Analyse failure cases (Francesco, ABT)
  • Develop concept for SE interlocking within the next ~6 months (OP, ABT, MPP). It should then be discussed in the MPP.