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

'''DISCUSSION MATERIAL'''

[https://wiki.jlab.org/cuawiki/images/1/15/NPS_mechanical_design_01-31-2019_JLab_meeting.pptx 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 ([[Media:comcal_controls.pdf | 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