Calibration Progress Report 

Today I'd like to take a look at the event counting rate between the North and the South detector. I've noticed that through out the calibration process, center cut events show good matching counting rate between N and S, but not the whole event sample. Since I believe calibration is at this point quite stable, I wanted to revisit this issue.

Fig. 1. North and South counting rate for 2 photon events

Fig. 2. Channel by channel photon counting rate for two photon events -> pdf version

So we see that for most channels, the match is very good, and the mismatch seems to be concentrated on a handful of channels. Here are two of them that seem most obvious. 

Fig. 3. Row 0 Column 0 photon counting rate for two photon events

Fig. 4. Row 0 Column 0 Mgg/Mpi0 distribution for two photon events

So by relying on mass, this pair will not go in the right direction. Also, the energy spectrum suggests few percent correction, whereas the masses are both pretty close to the target value. 

Fig. 5. Row 5 Column 1 photon counting rate for two photon events

Fig. 4. Row 5 Column 1 Mgg/Mpi0 distribution for two photon events

This pair will go in the right direction, but the magnitude might not be right. 

Finally, this channel seems to have some issue with the north. 

Fig. 7. Row 6 Column 0 photon counting rate for two photon events