General EEEMCal Meeting Summary 2/4/22
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PARTICIPANTS: Vladimir Berdnikov, Carlos Munoz, Douglas Hasell, Hamlet Mkrtchyan, Hrachya Mrukyan, Irina Shestakova, Olivier Philip, Vardan Tadevosyan, Tanja Horn, Nathaly Santiesteban, Renee Fatemi
UPDATE FROM 2021 PROTOTYPE TESTS AT JLAB
- Question about pair spectrometer energy measurement - more information about Hall D pair spectrometer
- design and construction: https://www.osti.gov/pages/servlets/purl/1211526 and https://arxiv.org/pdf/2005.14272.pdf
- commissioning: https://www.osti.gov/pages/servlets/purl/1361404
- Question about new powder used in fabrication of PWO crystals
- no performance difference (light yield, transmittance, radiation hardness, etc.) observed for crystals made with pre-mixed powder from BTCP (purchased by Giessen U.) and crystals made with new powder. All crystals were made at CRYTUR
- beam tests also show no difference in performance
- Gain measured for SiPM?
- yes but with different electronics (higher gain amplifier from BDX style electronics)
- Next want to measure SPE with same amplifier to directly convert
- One discussion point: need for measurement of absolute light yield for SciGlass
- For small samples one measures up to 100 times higher light yield than PWO
- For scaled up samples the produced light yield is still high, but detection at photocathode lower as transmittance becomes more challenging. For current samples measure light output consistent with that from PWO-I, about half of PWO-II.
- Plan to quantify this
- Joined EIC SiPM meeting: https://indico.bnl.gov/event/14715/ and in particular the discussion on EM calorimeters as it is relevant to EEEMCAL
- EEEMCAL considerations:
- Linearity is critical in full dynamic range, up to 20 GeV
- One 6x6 mm^2 SiPM per crystal showed loss in calorimeter performance compared to PMT RO
- Configuration with 3x3 mm^2 SiPM required 16 preamps ----> cooling issue, electronics cost
- PWO EEEMCAL need ~12um pixel pitch SiPMs with 6x6 mm^2 dimension. Customize matrix 2x2(?)
- Glass part will need SiPMs with bigger pixel pitch (15-50)um and good photon detection efficiency (PDE). Final number strongly depends on exact technology, e.g., SciGlass vs LeadGlass.
- Glass surface is four times bigger ---> use of light guides (potential light loss) versus big sensitive surface matrix of SiPMs.
NEXT MEETING: FRIDAY 25 FEBRUARY AT 8AM ET