May 17, 2023, FCAL Insert Installation Meeting

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Meeting Time and Place =

Wednesday May 17, 2023 9am At Jefferson Lab, Hall D Counting House and on Zoom meeting ID: 161 944 9114 Passcode: 562689



  • Reviewed minutes from last meeting
    • Discussed shimming of existing FCAL
      • No shims found until the center stainless steel tube. Shimmed with 1 80um shim where no strap against the tube as expected
      • Shims on edge steps 0.5 to 1.5mm. Was 1.5 mm by design
      • One of the lower rows had various shims 80 - 160 um?
      • 1st row had 80um every other module
      • Module height at some rows varied as much as 350 um with no shims.
      • looks like it was determined at some point in time it was decided that shimming added no value except at critical areas such as the beampipe
    • Malte gave update that all modules were removed as of yesterday - unstacking is complete!
    • Discussed need for stacking map - will have large printout with orientation and color code (blue or green)
    • Sasha ordered cable labler
    • Sasha wishes to assemble cables in ESB - should be fine
    • Stephanie and Arshak have a basic plan for LMS box and fibers that appears to be workable
    • Lead Glass module Stacking test in ESB - existing FCAL 40.141 mm per block on average
      • 1st row stacked - 15 modules -
        • 40.164 mm average module width before squeezing
        • 40.111 mm average module width after squeezing less than 3 inch-lbs per screw
        • 53um per module change - 800um for entire row.
        • 40.137 mm ave after release - 26um per module - 390um spring back
      • 2nd row stacked - 21 modules - same block
        • 40.18 mm initial width
        • 40.14 mm final after squeeze 2 in-lbs
      • 1st 2 blocks in 3rd row were placed and fit just right
      • Installed a piece of the 1/32" ThermaCool R10404 on vertical beam left edge and compressed it
        • 3 in-lb torque per bolt, approx. 160 lbs total over 18 sq. inches - 9 psi - 62kPa
        • Was very tight and could not be pulled out with moderate force
        • Probably makes sense to use this pad on beam left side only to take up any cooling shrinkage differential
  • Ready for crystal stacking test - Sasha, Vlad, Arshak
  • Tim is updating tech version of stacking procedure document