I tried to search for the reason of unexpected variation of CAL response vs energy noticed by Carmelo while he compared p7 reprocessed data with existing data.
During original processing we used 2 MevPerDAC calibration files:
- fit_protonCalib_calibOps_17runs.calMPD.xml
- based on data collected Jul15, 2008
- used to process data in August - October, 2008
- fit_protonCalib_nomoSciOps_week26sep3oct2008_sum_try2.calMPD.xml
- based on data collected Sep 26 - Oct 3, 2008
- used to process all data since November 2008
For pass7 reprocessing we used 17 new MPD calibration files each based on 6 Ms of data and used to reprocess data for the same period
Following plot shows the evolution of average ratio of calibration coefficients for HE and LE diodes with time for old calibration files (red points) and new calibration files (blue points).
All values on the plot are divided by 53.15 (actual mean ratio of MeVPerDAC coefficients of HE and LE diodes).