SPS extraction sextupoles + bumpers WIC interlocks

Monday 15 Sept 2025, 13:30 → 14:00 Europe/Zurich

A. Colinet, A. Dutruel, K. Li, R. Mompo, J. Ridewood, I. Romera

WIC

Only the MAINS and the Ring-Line (i.e. LSF/LSD, LOD and LOF, but not the LQSA circuits) are included in the SPS Ring user permits provided by the WIC in all the BAs.

Post-LS3, with the renovation of the PCs in the SPS, should we add the extraction sextupoles + bumpers to the user permits given to the SPS ring BIS? 

Pros:

• Real hardware interlock on these elements in case they trip (on top of the regulation error already foreseen)
• Potentially a faster reaction time?

Cons:

• Availability: if one of these elements trips, the WIC user permit will be FALSE, hence preventing all SPS operation. There is no possibility to mask a single circuit at the level of the WIC. On the side of the BIS, if we mask, we mask the entire WIC interlocks (not recommended, that's why the WIC are connected to unmaskable inputs today).
• Other possible implementation: add extra CIBUs dedicated to these elements and connect them to the BIS in BA2 to consider them based on the destination flag. This solution requires costly extra infrastructure (extra cables/fibres from BA1/2/4/5/6 to North Area BIC in BA2).

 

Decision: The WIC user permits will not include the extraction sextupoles + bumpers. The situation will remain the same as pre-LS3. EDMS 2887843 to be updated to remove these elements from the WIC interlocks.

Note: Monitoring of the magnet overheating is still possible via the WIC GUI.

Regulation error interlocks

EPC will provide regulation error interlocks for all the extraction sextupoles + bumpers. These elements will be on maskable channels so that a breakdown will not prevent the SPS from delivering to unaffected users. Potentially, the SBF used to mask these elements can be forced to TRUE permanently (i.e. regardless of the beam intensity).

It has yet to be decided if these regulation error interlocks will be connected to the North Area extraction BIS, and in this case only interlocked in slow extraction cycles, or connected to the SPS ring BIS. In this case, they would be interlocked regardless of the cycle, and could be masked if they break down to continue serving the beam to the other SPS destinations.

This topic will have to come to a conclusion soon to freeze the infrastructure requests.

13:30 → 13:50 SPS extraction sextupoles + bumpers WIC interlocks

• should the PC status of these elements be included in the WIC user permits of the SPS ring BIS?
• should the magnet overheating be included in the WIC user permits of the SPS ring BIS?

Speaker: Antoine Colinet (CERN)