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Light Yeld estimate for a ECal crystal (old BTCP PbWO) from the HPS proposal  pag. 157, top-left panel . These are the measurements we performed in Genova, with a HPS-like crystal (from CLAS-IC),  a LA-APD, and a FT-Cal amplifier. The mean energy deposited in the crystal by cosmics is ~ 15 MeV. The corresponding mean charge collected is ~ 25 pC.The amplifier and APD gain were, respectively, 1800 and 150.  Measure was performed at 18 +++ 1 deg. This gives an average LY of : 25 / (1800 * 150 * 1.6E-7 *15) ~ 35 phe / MeV

"PbWO4 light output" email thread

O.Pogorelko's presentation where he takes 12 p.e./MeV and multiplies by 3 for "our crystals" and comes up with with "3.6 p.e./MeV at APD".  If we assume that 3.6 does not include QA=0.75 of APD, than real p.e./MeV will be 2.7. To many inconsistency. I think we should rely on what we (Andrea) measured.

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