Check VETO energy calibration
I checked the VETO energy response in the positron runs.
I started by looking at run 8298 (h^+
calibration run), comparing data and MC. Data was reconstructed using calib. constants currently on master
.
The following plot shows the VETO-1 energy response; in black, the data, in red, MC. A horizontal scale factor was introduced in the simulation to match the data, but the value of this factor was found to be 1.017, i.e. very close to unit.
This means that the VETO calibration is very good, and MC reproduces very well the data.
Then, I looked at dimuon events from run 8310, comparing again data with MC. Same calibration constants are used. The result is reported below (blue is data, red MC):
In this case, the data energy calibration looks a little bit over-estimated. Is this possible that this effect is due to the gain-dependency of PMTs on the average light level they are exposed to, as we see in ECAL/HCAL? Calibrations were determined from muon runs, probably with low intensity.
@samoylen , may I ask you if you had ever notice this effect? Maybe I am making some mistakes in this analysis, thus any input and help from you would be highly welcome!