September 25, 2019 FCAL Insert Design Meeting

Meeting Time and Place

Wednesday Sept 25 1:30 pm At Jefferson Lab, room TED 2504

• Present - Sasha Somov, Josh Crafts, Eugene, Stephanie, Keith Harding, Tim, Fernando, Chris Stanislav

Agenda

• Action items from last meeting https://halldweb.jlab.org/wiki/index.php/September_9,_2019_FCAL_Insert_Design_Meeting#Agenda
• Discuss Center tube
  • 1mm thick wall minimum. ID is 3.8 cm
  • Upstream end flush with upstream face of acrylic
• Discuss Tungsten absorber
  • Cover 1.5 crystals ok?
  • Rohacell supported
• Monitoring System
  • Use 1/2" Acrylic sheet with 45 degree angles on edges
  • How to attach fibers? Media:Acrylic_sheet.pdf
  • What size fibers?
  • Ok to make test piece as shown?
• Cooling of blocks - 2.1 KW needed
  • 2 Chillers like those used for BCAL ($16K ea)
  • 4 water to air Heat exchangers around crystal area
  • 9 parallel circuits for each chiller
  • potted copper tube into aluminum blocks
  • Cooling of inner tube - removable plate
  • Proposed manifold similar to BCAL
• Support structure and assy sequence
• electronics patch panels DS of crystal pmts
• Discussed Brazing of PMT module straps and new mag field tests
  • Sasha wishes to assemble a new 9 module array for magnetic field testing
    • 18mm diameter light guides are needed - josh found some on Amazon - tim will order
    • 6mm longer with 50 micron larger ID mag shield steel needed - Submitted to machine shop Media:1020_shield.pdf
    • additional mu metal shields needed (same as previous - 350 microns) - Tim ordered Due Oct 18-
    • Have steel shields annealed - Tim looking into it >900C
• Discuss test fixture for PMTs in beam
  • Need to fabricate steel case - Media:Steel_shield.pdf
  • need to fabricate support structure - Tim
  • Need to fabricate feedthru panel - Josh/Tim
  • need to fabricated aluminum base plate - Josh/Tim

Minutes and Action Items

• Inner Tube
  • ok to use 2mm wall
• Acrylic Monitoring sheet
  • make 1/2" thick with 6mm bevel on outer edges only
  • Drill holes with diamond end mill for polished bottom
  • 1mm fiber probably ok
  • look at putting a rubber gasket on end flange of modules to prevent cross talk
  • make test piece Determine size to fit in dark box
• Cooling Manifold
  • Need to make sure there is room to replace FCAL module electronics
  • Need humidity control in dark room
• Electronics Patch Panels
  • Fernando informed us that a 48 wire cable will be used for HV
  • HV cables carries 48 individual wires, large bend radius Media:Radiall_connector.pdf
  • PCB mounted connector to bring power from Radiall to individual bases Media:SamtekHV.pdf
  • still need 1600 signal connectors on patch panel using same connectors as ComCal
  • Layout separate HV and signal patch panels - Keith