1) We have already seen the effect of the pedestal drift on crystal energy and on the total raw energy :
(run700002024 - 100 GeV - left: lin scale, right: log scale):
2) Let's look at layer energies (run700002024 - 100 GeV):
From layer 4 to 7, you can clearly see that range 3 is correct but range 2 has collapsed.
3) At the beginning of SPS, we have taken runs changing the trigger rate (run700001782 to 70001787 - 200 GeV)
Let's look at the what happens to CalELayer2 as function of rate :
What's surprising is that range 2 can be bad even for large GemDeltaEventTime.
4) Let's look at the fraction of bad energy measurement (run700001782 - 4200 evts/spill)
5) Let's look at the fraction of bad energy measurement in a standard run (run700002024 - 1000 evts/spill)
So it seems that there will always be a pollution of events with a bad energy measurement.
6) Are bad measurements correlated between layers ? (run700002024 - 1000 evts/spill)
And the situation is the same even when requiring that GemDeltaEventTime>10000 :
So the pollution at large values of GemDeltaEventTime with respect to the total energy measurement (i.e. at least one layer was badly measured) can be of the order of 5%.
