Requirements for interlocking the LSS4 bumpers in the SX cycles - follow-up

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A. Colinet, M. Fraser, K. Li, D. Nisbet, J. Ridewood, I. Romera, F. Velotti

 

Proposal for the LSS2, LSS4, LSS6 bumpers

Instead of connecting the current monitoring of the LSSx bumpers to the extraction BICs, it is proposed to connect them to their nearest SPS Ring BICs.

This is made possible by the replacement of the FEI interlocks by FGC3 post-LS3. Legacy FEI provided a single point evaluation of the current at flat-top, while the FGC3 will provide a continuous monitoring of the current.

The advantages of this solution are:

  • Reduced infrastructure costs
  • Have ring PCs actually interlocked with the ring BIS (more logical)
  • These interlocks would request a beam dump instead of inhibiting the extraction
    • Beam dumped earlier, at a lower energy
    • Less energy deposited on the SPS beam dump

 

These interlocks would have to be maskable which is the case today for the LSS4 and LSS6 PC interlocks.

Action Antoine: this proposal needs to be validated by the MPP, follow-up with Jan/Daniel.

Proposal for the extraction sextupoles (BA1, 2, 4, 5, 6)

Initially it was foreseen to connect all extraction sextupoles current monitoring interlocks to the BA2 slow extraction BIC, which means pulling long fibres from many BAs to BA2.

It is now proposed to connect all extraction sextupoles to their nearest SPS Ring BIC, in order to act on the SPS Ring BIS instead of the NA slow extraction BIS. Functionally, the interlocking matrix is the same as these interlocks were considered regardless of the beam destination.

 

OP considerations:

Beam transfer functions are not necessarily defined for all SPS users, i.e. LHC users don't define transfer functions for the extraction sextupoles for example.

Today the extraction sextupoles are managed in the North Area transfer, it is proposed to move all SPS elements to the SPS ring particle transfer instead.

Action (James + Kevin): discuss this proposal with Stephane + Michi

 

Notes on the follow-up between Ivan and Antoine on the DIC/DIF modifications

  • BA4
    • Merge LSS4 bumpers + extraction sextupoles to BA4.CIBFX.4
    • Action: remove BA4 fibre request from NACONS DIF
    • Action: Update BIC destination in SPSCONS DIF (destination should now be CIB.BA4.S4, instead of TT40A)
    • No action on David's cabling request (LSS4 bumpers + sextupoles were already foreseen to be connected to the same rack)
  • BA6
    • All 9 bumpers (BA6.CIBFX.1) will be connected to CIB.BA6.S6 instead of TT60A
    • Addition of extraction sextupole (x1) to BA6.CIBFX.1
    • both MSE and MST connected to BA6.CIBFX.2 (still connected to TT60A)
    • Action: change BIC destination in SPSCONS DIF for BA6.CIBFX.1
    • Action: Remove BA6 fibre from NACONS DIF
    • No action on David's cabling request (LSS6 bumpers + sextupoles + MSE/MST are all connected to the same rack)
  • BA1
    • Action: Change destination in NACONS DIF to CIB.BA1.S1 instead of BA2 NA BIC (RA0404)
  • BA5
    • Action: Change destination in NACONS DIF to CIB.BA5.S5 instead of BA2 NA BIC (RA2603)
  • BA2
    • Action: Change destination in NACONS DIF to CIB.BA2.S2 instead of BA2 NA BIC (RA1314 instead of RA1313)

 

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