Dear all, here is the link to the CLAS12 Forward Tagger TDR http://www.ge.infn.it/~batta/jlab/ft-tdr.2.0.pdf You will find results of LY measurement with BCTP PbWO-II crystals coupled to PMT and a 10x10 APD at pg 27 Andrea will send around the same estimate for a ECal crystal (old BTCP PbWO) soon Cheers Marco