NPS Frame and Infrastructure Meeting (JLab, 1/31/2019)

DISCUSSION MATERIAL

Frame mechanical design

ACTION ITEMS

• PMT assembly

• as long as use non-magnetic material for the cylindrical tubes holding divider should be ok
• suggestion to use a standoff screw - would move access further to the back for easier access

• Cables, PCB, connectors

• need to check if can also increase vertical size - might hit SHMS water lines
• piece still needed to finalize for cable routing: NPS to front of SHMS
• discussion about grounding - might want to check with prototype and optical path disconnected - still see signal?
• cable making responsibility
• need to identify responsibilities for module assembly

• Thermal aspects

• find out dew point in experimental hall (need to make sure water will not condense/drip on components and heat exchanger inside NPS frame)

• Radiation hardness carbon fiber

• place sample in hall (give it to Brad S)

• Slow Controls / Logging for temperatures

• Readout hardware for temp probes TBD(?)
• Integrate into 'COMCAL' system ( Control and monitoring -- Egiyan?)

SUMMARY NOTES

• PCB Interface (HV, anode current, LED; 25cm(W) x 80cm(H))- updated design to improve access to PMTs

• Calorimeter design still same - plan to work on in Feb/March

• Reflector test for cross talk (Ho San) - result suggests negligible, no tedlar needed

• Calorimeter support - design to be finalized and check with mock-up, plan to work on Feb-April

• New PMT assembly design

• Only need to unscrew in one place now
• Captive screws - cannot fall during (de)installation
• Long cylinder tubes hold divider assembly

• Cables, PCB, and connectors

• PCB has been successfully constructed and tested - ready for construction

• Signal: sma
• HV: Fisher
• LED command connector: Samtec

• Increased box size to have more room for pushing cables left/right - gives more slack for cables, top of box LED connection is fixed
• review of cable routing plans from (11/13-11/15/2018)

• Signal: special patch panel to go from LEMO to BNC - RJ178 seems preferred as less bulky
• HV: multi-channel
• all cable connectors are on top of the detector box - LEMO as fits better

• discussion about making cables and cost

• 20 euro/cable (parts and labor), rate=4 cables/hour (need 250 hours labor)
• drawings and instructions prepared by IPNO

• discussion about module assembly

• many parts of the process (c)should be done by collaboration, some things like pre-shaping of the reflector might be better to do external

• Thermal aspects

• Crystal + external zone (intermediate and heating zones, 500mW/channel -> 540 W)
• Most important is the temperature stability
• Heating zone cooled by two heat exchangers, fans, and one chiller - effectively over-dimension (create a temperature bath) since have no idea about the air flow in that region, many cables
• discussion about temperature monitoring

• planned for front and back of crystals, no space in-between

• discussion about condensation

• if/if not need a dryer depends on temperature that run bottom heat exchanger to get 3kW, humidity in hall usually not that high
• if need a dryer could use a system like Hall A's

• Radiation hardness test of carbon fiber material in hall - preferably during high current running