JEF meeting, June 28, 2019
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Meeting time and location= 1:00 pm EST (JLab time) F228
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Agenda
Minutes
Attendees: Wolfgan, Josh, Simon, Sasha, Zisis
- Magnetic field studies more or less complete
- From last time: Sasha suggested moving FCAL assembly 35 cm downstream to reduce field in PMT region for lead tungstate
- Could stack lead glass blocks that we remove from the central region in the outer radius to improve acceptance
- Studies with 350 micron mu-metal shielding + iron housing look promising -- added additional 50 micron mu-metal
- For 60 Gauss longitudinal external field -> 2 Gauss in center of housing+mu-metal shield
- PMT response in central position of 3x3 array flat up to about 40-50 Gauss longitudinal field
- No saturation of mu-metal seen
- Currently using 1020 steel, could be annealed for ~20-30% improvement
- From last time: Sasha suggested moving FCAL assembly 35 cm downstream to reduce field in PMT region for lead tungstate
- Stacking: insert needs to be well-leveled to distribute load
- Consider adding ~few mm thick plates (above and below insert) in addition to shims
- 1/2-1 FTEs next fiscal year to work on frame and other designs aspects
- Cabling/connectors: Hall C style? (lemo for signals?)
- Second arm of pair spectrometer now ready for use for parasitic measurements
- Josh working on design for assembly to mount 12 crystals at a time
- Need to consider magnetic field from fringe field of Hall-D solenoid
- Zisis can provide summer undergrad students next year, considering putting graduate student of project