Difference between revisions of "Summary 2/1/19"

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CRYSTALS (Vladimir)
 
CRYSTALS (Vladimir)
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 +
* Discussion on crystal quality and tests
 +
::* Measured 2%/sqrtE with 3x3 prototype as expected given limitations of instrument - essentially have 8 edge crystals
 +
::* For NPS 12x12 prototype tests used temperature sensors on front and back of crystals
 +
 +
* Action Item: Make a spectrum of photon energy for crystals next to the one hit - should address question about smallest signal digitization - estimate is 2-3% of energy of hit crystal
 +
 +
* Saturation fADC - nominal voltage for linear range is 1100 V for HV divider, but this saturates. In Hall D tests ran with 650 V
 +
::* Rates comparable to NPS (250 kHz/channel)
 +
::* threshold >2 GeV overall (10-15mV/channel)

Revision as of 11:04, 3 February 2019

ACTION ITEMS

List of Action Items for ERR


SUMMARY NOTES

INTRODUCTION - ACTION ITEMS AND ERR (Tanja)

  • For ERR in general need a list of outstanding scope and how/who will address it
  • Discussion based on action item 2018 list in slides:
  • page 1 items:
  • Need an installation plan (Walter, Steve L. and team...)
  • demonstrate that design complete and floor layout plan exists
  • show what scope of work remains and who will do it
  • show that fringe fields under control
  • page 2 items:
  • cabling - show that there is a plan how cables go on carriage
  • page 3 items:
  • what to show for software, DAQ, and electronics...


MAGNET UPDATE (Charles)

  • Assembly done, ready for power and cooling - in test lab will get to 20% of power due to cooling limitations
  • no need to power up before ERR
  • plan to power up in summer
  • June might be good time as tech teams should have more time then
  • need to have estimate of fringe fields for magnet test area
  • might want to check modeling magnet with and without base plate (concern is additional magnetic material) - might be ok with 20% energizing
  • Mapper is ready for magnet tests
  • need to start on safety documentation - J. Beaufait, E. Folts can help
  • mapping plan is expected to be developed in first half of February - idea is to run without field and devise plan based on that
  • Fringe fields
  • show that no impact on beamline magnets - earlier studies showed that no impact, but might want to check again
  • for ERR mainly need to show that have a plan


FRAME (Emmanuel)

  • Design mostly ready - main question is who will do assembly
  • Impact of cross talk in neighboring modules
  • Ho-San measured 0.5% of light (from regular showers) goes from one to next crystal - expect same for LED
  • Check on vertical clearance for PCB interface box - there may be interference with SHMS water lines
  • For PMTs and electronics interface, need to know smallest signal size that still needs to be digitized
  • Discussion crystal-PMT attachment and crystal array design
  • Assume that silicone cookie will stick to either crystal or PMT when removing PMT
  • Crystal array assembly is new - using aveoles (material only at first ~2cm along block, everywhere else along block 0.3mm air between crystals). Just put crystal inside, no compression.
  • NOTE: to quantify shower leakage could run simulation and make shower profile with and without gaps
  • Survey requirements
  • standard is survey to 1mm on fiducial block on outside of frame
  • For Hall A DVCS surveyed all block locations. Note that calorimeter was at 1m from target, so mm offset results in 1mrad
  • calibration with e-p elastics possible? Need to check if can adjust calorimeter (in x, y, z) for these kinematics - in principle can do that with screw adjustments or shims


CRYSTALS (Vladimir)

  • Discussion on crystal quality and tests
  • Measured 2%/sqrtE with 3x3 prototype as expected given limitations of instrument - essentially have 8 edge crystals
  • For NPS 12x12 prototype tests used temperature sensors on front and back of crystals
  • Action Item: Make a spectrum of photon energy for crystals next to the one hit - should address question about smallest signal digitization - estimate is 2-3% of energy of hit crystal
  • Saturation fADC - nominal voltage for linear range is 1100 V for HV divider, but this saturates. In Hall D tests ran with 650 V
  • Rates comparable to NPS (250 kHz/channel)
  • threshold >2 GeV overall (10-15mV/channel)