Comments on crystal LY losses due to 20GeV proton irradiation D Cockerill 29.1.2009 Data NIMA 545 Table 3 and Fig.18 NIMA 564 Fig 3 (top) Force fit through 0,0 Force fit through 54.1012 p/cm2 Fit result 96*(1-exp(-0.13*flux) flux in units of 1012 Chisq = 4 Note MOST important data at ~10.1012 p/cm2 Governs VERY fast appearance of damage at early stage !!!!!!!!!!!!! Less relative damage after 30.1012 LY loss (%) Proton flux*1012 / cm2

LY losses across the ECAL due to hadron generated ‘stars’ Comments on crystal LY losses due to 20GeV proton irradiation D Cockerill 29.1.2009 Barrel Endcap LY loss (%) 100fb-1 high L, 1yr 500fb-1 end LHC 3500fb-1 end SLHC 50fb-1 25fb-1 10fb-1 LHC start Eta LY losses across the ECAL due to hadron generated ‘stars’

Comments on crystal LY losses due to 20GeV proton irradiation D Cockerill 29.1.2009 Region of 50% LY loss or more, at end LHC (500fb-1) 56 SCs per Dee, 224 SCs (5600 crystals) in total for EE 4 out of 25 ECAL eta ‘good’ trigger tower regions (to eta=2.5)

To do: CHECK – these plots! Comments on crystal LY losses due to 20GeV proton irradiation D Cockerill 29.1.2009 Significant, measurable effects at LHC startup (LOOK for them!) Half light gone at eta=2 by end of standard LHC running Wiped out by end of SLHC BUT What is light collection profile along xtals with star density creation Cosmics data (NIMA 564) from whole xtal only Very interesting to get LY with distance in new CR stand May lose light on em showers (first 10 Xo) but not for hadron shower energy deposits which get right to back of xtal ECAL could still be used as an HCAL layer 0 possibly at inner radii To do: CHECK – these plots!

Comments on crystal LY losses due to 20GeV proton irradiation D Cockerill 29.1.2009 STRAWS to clutch at, in hope, Proton irradiations done at VERY high rate - factor 140 vs normal LHC at injection Could this leave a highly CHARGED xtal internally leading to odd 2nd order effects not normally seen? Odd, Rayleigh scattering – totally unlike gamma colour centres Odd, if crystaline effect, annealing possible at such a low temp (250-350oC) Does xtal anneal faster/further at 100oC than at 20oC?? Annealing with UV/other lamps, laser, double excitatation, focussed ultrasound, xrays Bake out endcaps in shutdowns (not only LHC!) ?