September 25, 2019 FCAL Insert Design Meeting
From GlueXWiki
Meeting Time and Place
Wednesday Sept 5 1pm At Jefferson Lab, room TED 2504
- Present - Sasha Somov, Josh Crafts, Vlad, Eugene, Stephanie, Keith Harding, Tim
Agenda
- Discuss 40x40 crystal assembly with 19 Lead glass modules around
- Crystals move to 12.5 cm from US face of lead glass
- 40x40 crystal matrix starts with shim to be able to go to 32x32 fairly easy.
- Decision to pre-measure stacks of crystals and the existing FCAL to determine bottom row offsets
- Discuss installing Rohacel US of crystals to fill hole and support the lead glass blocks
- Rohacel properties Media:Rohacel cut sheet.pdf
- Radiation Hardness https://p25ext.lanl.gov/phenix/mvd/notes/1997/PHENIX-MVD-97-5/radiation.html
- http://www.phenix.bnl.gov/WWW/publish/bosze/phenixnote272/radiation.html (same data)
- Discuss Tungsten absorber
- Cover 1.5 crystals ok?
- Rohacell supported
- Monitoring System
- Use Acrylic sheet, how thick?
- How to attach fibers?
- 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 - removeable plate
- electronics patch panels DS of crystal pmts
- Brass strap soldering progress
Minutes and Action Items
- Discussed the center support tube
- Need to determine material for center tube - Sasha
- consider magnetic properties, thermal conductivity, strength, stiffness
- Need to determine the maximum hole size allowable (assume steel initially) - Tim
- Need to move the upstream end flush with US side of acrylic sheet - Keith
- Need to decide on size of hole (2x2 crystals now) - Sasha
- Need to determine material for center tube - Sasha
- Discussed Monitoring system
- Use 1/2" acrylic sheet same as FCAL
- Discussed possibility of pre-assembling the acrylic, fibers and rohacell
- Determine diameter of fibers - Sasha
- Layout fibers coming through rohacell and cut angles on acrylic - Keith/Tim
- Add fibers to inner hole edge
- Fabricate a test piece - Tim/Keith/Josh
- Discussed feedthru panels attached to cable support chains
- Cables are stiff, ok to attach panels to cables with hinge
- Use ComCal feedthu sizing to develop panels - Keith
- Cables should be strain relived to chains
- Discussed cooling system
- Concept to glue copper tubes to aluminum blocks with thermally conductive epoxy accepted
- Concept to clamp cooling plates to inner support tube accepted
- Assuming 2.1KW total heat load, we would need 2 of the chillers used for BCAL.
- Continue with connections and manifold layou - Keith/Tim
- Discussed Brazing of PMT module straps and new mag field tests
- Josh has successfully brazed and cleaned (warm water) an assembly and is testing
- Test with 2mm cookie to ensure enough pressure can be maintained for good transmission - Josh
- Sasha wishes to assemble a new 9 module array for magnetic field testing
- 18mm diameter light guides are needed - Tim
- 6mm longer with 50 micron larger ID mag shield steel needed - Tim
- additional mu metal shields needed (same as previous - 350 microns) - Tim
- Have steel shields annealed - Tim
- Discussed test fixutre for PMTs in beam
- Need to fabricate steel case - Tim
- need to fabricate support structure - Tim
- Need to fabricate feedthru panel - Josh/Tim
- need to fabricated aluminum base plate - Josh/Tim