October 19, 2022 FCAL Insert Installation Meeting

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Meeting Time and Place

Wednesday October 19, 2022 10am At Jefferson Lab, Hall D Counting House and on Teams


  • Minutes from last meeting https://halldweb.jlab.org/wiki/index.php/October_05,_2022_FCAL_Insert_Installation_Meeting
  • Discuss Lead Glass and crystal module removal/install [1] - Sasha
  • Discuss cable mapping - Sasha
    • Existing cables
    • New Cables
  • Cable quotes Chris S.
  • Patch Panel requirements
  • Initial testing of modules before removal - Mark D.
  • Revisited removal of darkroom -
    • All cables need to be removed from darkroom to be able to install new detector
    • may be able to only partially remove Framing
    • Maybe able to crane frame off platform partially assemble
    • Rework for patch panels
  • Updated Schedule
  • Monitoring system discussion
  • Assembly in ESB
  • Media:FCAL2_strawman_schedule.pdf
Both step.jpeg
JBweld cooling test.jpeg
Glass module steps.jpeg
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Work platform bird.png


  • Reviewed minutes from previous meeting
  • Sasha showed wiki page he started for FCAL2 installation
    • gave 7 possible categories of condition of existing glass modules
    • Lead glass modules have aluminum towards glass
    • Crystals have mylar towards crystal
    • Sasha estimates 40 minutes to rewrap a module with proper training
    • Need to determin qty or al mylar, silicone sheet and what else needs to be procured
    • Suggested students can do wrapping
    • Showed HV and current for each existing module
    • maybe 2 people from Cuevas to help with unstacking and stacking
    • Tech group will have availability during this time
    • Detector support group may have folks available to help
  • Sasha needs more time for cable mapping - will make separate meeting
  • Mark Dalton presented status of existing modules in 4 categories
    • 187 original bases saturated
    • 206 new bases saturated
    • 1018 new bases < 1790V
    • 1309 original bases < 1790V
  • Possibility to mark prior to removal
  • Maybe perform stress test on existing modules to see condition prior to removal
  • Maybe remove bad bases before unstacking - need to plug end so pmt does not fall out
  • Have about 50 good spare pmts besides 400 that will not be used
  • discussed pre-sorting as removing from stack vs. just toss them in a bin for sort later
  • Need to work out sorting procedure to determine required shelving
  • do we also wish to inspect from US side prior to unstacking to label cracked or brown ones?
  • Chris S. ordered 1600 RG174 signal cables and connectors - 20 weeks - $83K
  • Have all external HV cables on connectors - they still need to be attached
  • Lengths are needed for all HV and LV cables inside dark room
  • LV cables are ribbon cables inside dark room
    • No daisy chaining
    • Can we reduce to 3 wire instead of 10 to save space?
  • Monitoring Panel
    • fibers have about a 1" bending radius with 10% loss in signal
    • Leave clearance on side edges of Rohacell to allow fibers to come out and bend around US surface of outer monitoring panel
    • Outer plexiglass and rohacell can be held together using plastic push pins
    • Need to get details from Matt S. for outer LED attachments
    • discussed need for gasket on from brass face of each crystal to reduce possibility of cross talk
    • Sasha discussed changing to individual fibers for each crystal
      • is this needed for calibration?
      • what is the requirement for the monitoring system?
      • continue with the current design
      • Final decision needed by December
      • Arshak doing more studies
  • Cable trays to be determined once cable configuration is defined

Action Items

  • Set up separate meeting for Cable mapping and requirements - Tim
  • Continue to work on unstacking, categorizing and repair plan - Sasha, Mark D.?
  • Develop layout for patch panels - Stephanie/Chris S
  • Continue to develop current monitoring design - Stephanie/Arshak
  • Work on cable tray layout - Tim/Stephanie
  • Provide lengths for HV and LV cables inside dark room - Tim/Stephanie