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    Discussion on LBDS upgrade

    → Europe/Zurich
    865/1-B03 (CERN)

    865/1-B03

    CERN

    12
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    Present: Anton, Valeria, Tobias, Francois-Xavier, Antonio, Yann, Chiara
     

    Main outcome from LBDS upgrade discussion:

     
    I asked Jan Borburgh if we can envisage just replacing blocks inside the existing modules and he answered that this is not a problem (just insure that crazy physicists do not do MDs on asynchronous beam dumps which might activate  too much these objects!). My dream is to be able to change the scope and be able to solve all the issues by replacing present with better materials using only the presently allocated budget.
     
    1) Possible thinking of characterising different materials (CFC, 3DCC, etc), as we are doing for SIGRAFLEX, to get out of grey zone? Not only HL-LHC but wider interest for collimation and protection of future machines (short in time for HL-LHC if answer needed by end 2020). 
    2) TCDQ: 
    • Check effect of replacing critical blocks with 3DCC (BMI and TCD)  ==> keep in mind possible issues with coating (second order problem)
    • Get from the project ok about assumptions on official optics and thus minimum allowed gap (Chiara)
    • Check if type 2 erratic still on the table after MKD triggering and retriggering upgrade (ABT)
    • Questions for ABT: metrology measurements on flatness of present TCDQ. Why did we add a module during LS1?
    • BTP simulations:
      • Latest official optics and MKD waveforms (worst agreed failure scenario and minimum gap according) ==> sweep pattern at TCDQ (and TCDS) with most conservative beam conditions (2.3e11 protons and 1.7 um emittance)
      • Leakage from IR7 to TCDQ and TCSP in case of lifetime drop, any risk of quench?
    3) TCDS:
    • Study effect of changing material of blocks on existing 2 modules to improve TCDS survival (why Ti block?) and MSD protection (BMI and TCD). Initially studies can be done just putting a metal block after the TCDS and checking that it survives. When the best configuration is found one should look at the real geometry and check mu-metal deformation and pressure rise of water in cooling pipes.
    • Ideally try to see if we can avoid installing a third module since this does not seem to improve the situation without touching the existing ones. 
    4) TDE:
    • Define range of variation and errors on sweep pattern for different MKB waveforms (200 degrees different just using new MKB waveform) (BTP)
    • Define minimum possible time interval between consecutive dumps at top energy (BTP)                
    5) Very low priority: effect of D1 masks in reducing risk of D1 quench (BMI)
    6) Functional specifications (ABT with collaboration of BMI and TCD) with:
    • Present limits
    • Assumptions (optics, settings, beam intensity, emittance, etc)
    • Define error scenarios and explicitly exclude unacceptable situations (i.e. total loss of dilution, type2 erratic?, etc)  
     
    Restart regular monthly meetings in 2019.
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