1. 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 p/cm2
Fit result 96*(1-exp(-0.13*flux) flux in units of Chisq = 4
Note
MOST important data at ~ p/cm2 Governs VERY fast appearance of damage at early stage !!!!!!!!!!!!!
Less relative damage after
LY loss (%)
Proton flux*1012 / cm2

2. LY losses across the ECAL due to hadron generated ‘stars’
Comments on crystal LY losses due to 20GeV proton irradiation D Cockerill
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’

3. 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)

4. To do: CHECK – these plots!
Comments on crystal LY losses due to 20GeV proton irradiation D Cockerill
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!

5. 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 ( oC)
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!) ?