pi0 recalibration remarks

Recalibration with pi0 was performed by Kenichi Nakano. Details are on his webpage.
Here's a couple of remarks regarding his analysis. Kenichi made available root files with histograms containing invariant mass spectrum for each tower. These files are located here: /phenix/WWW/p/draft/kenichi/emcal/energy_calib_run6pp/mass_hist/ and a copy is here: /phenix/workarea/stkav/pi0recal/ hist_0.root contains initial spectra and hist_7.root contains final spectra after recalibration.
I extracted fit function parameters and calculated integral under gaus peak in each channel. This number should give an idea of number of pi0 in a given tower. Occupancies as a function of z and y are here. Minimum value is set to 10 pions in a tower.
The same plot with threshold of 100 is here. Calibration made on less than ~100 pions could be regarded as unreliable.

Some ASICs too high occupancies and a lot of area is below 100 pions threshold. Here're examples of invariant mass spectrum - normal, with few entries, with too many entries and weird.
  1. Some ASIC boards by the end of Run6 were found to have very low gain having good gain at the beggining of the Run. They passed LED quality analysis at the end of Run6. What's happened?
  2. In PbSc coffection coefficient map ASIC structure is clearly seen. Why?
Last update:
Andrey Kazantsev