Calibration Munich group version Checks

SWM UD, April 2004Nadia Tonello, MPI 2 Idea Calibration runs: same number of photons in all PMs Flat fielding: same pixels output from calibration runs Calibration methods: Ffactor method (relative calibration) Blind-pixel method (absolute calibration) We did consistency checks

SWM UD, April 2004Nadia Tonello, MPI 3 Jan – Feb 2004 Which method for calibration? 1. Blind pixel had (hardware?) problems: -many bad runs no calibration constants 2. Ffactor method: - reasonable results pedphotcalc.C - simple to check new independent class to compare the resulting conversion factors

SWM UD, April 2004Nadia Tonello, MPI 4 How we calibrate... How we calibrate... Same scheme as calibcalcphotons.C 1. Extraction of Pedestals from pedestal runs in FADCcounts using MPedCalcPedRun

SWM UD, April 2004Nadia Tonello, MPI 5 How we calibrate Calculation of calibration factors using signal estracted from calibration runs by MCalibrationChargeCalc etc. ~23 photoelectrons for inner pixel area

SWM UD, April 2004Nadia Tonello, MPI 6 How we calibrate NEW: Flat fielding of the number of photons in the calibration-run. ~135 photons for inner pixel area

SWM UD, April 2004Nadia Tonello, MPI 7 How we calibrate... NEW calibration factors: multiply the previously calculated with the correction factor for flat fielding. ~ 0.8 photons/ FADC count ~ 3.5 photons/ FADC count

SWM UD, April 2004Nadia Tonello, MPI 8 How we calibrate... 4.Calibration of data and pedestals using MCalibrate Data

SWM UD, April 2004Nadia Tonello, MPI 9 How we checked it: How we checked it: New Class to calculate the conversion factors with the Ffactor method (used instead of MCalibrationChargeCalc etc.) Q in Mean charge for the inner pixels excluding cosmics and bad pixels c i Correction factor to flat field the charges  Qm distribution obtained summing all the charge distributions of the pixels after flat fielding  red f rom the mean corrected pedestal RMS

SWM UD, April 2004Nadia Tonello, MPI 10 How we checked it: Q in Mean charge for the inner pixels excluding cosmics and bad pixels ~160 FADC counts channel

SWM UD, April 2004Nadia Tonello, MPI 11 How we checked it: c i Correction factor to flat field the charges ~160 FADC counts channel

SWM UD, April 2004Nadia Tonello, MPI 12 How we checked it:  Qm distribution obtained summing all the charge distributions of the pixels after flat fielding  Qm ~43 counts

SWM UD, April 2004Nadia Tonello, MPI 13 Mean number of photoelectrons N phel = (Q in 2 /  2 red ) F 2 where F 2 = (as in MCalibrationChargeCalc) Conversion factors: (Ph/FADCcount) i = N phel c i / Q in /phxpe where phxpe = 0.18 (as in MCalibrationChargeCalc)

SWM UD, April 2004Nadia Tonello, MPI 14 Result: Calibration factors in agreement ~ 0.8 photons/ FADC count ~ 3.5 photons/ FADC count

SWM UD, April 2004Nadia Tonello, MPI 15 Check inner-outer pixels: pe Inner pixels: 23 pe/area Outer pixels: 13 pe/area n peI = 1.8 n peO n pe = 0.18 n  n  I n peI = 5.6= n  O n peO = = 10 n  I = 0.25 n  O

SWM UD, April 2004Nadia Tonello, MPI 16 Check inner-outer pixels: F 2 /QE n peI =23 n peO =13 · 4 = 52 nOnInOnI n peO n peI = 2.22 n peO n peI = FI2FO2FI2FO2 n n peO n peI = n n peO QE O QE I n peI = QE I QE O FO2FI2FO2FI2 n peO n peI = 4 F 2 O QE O = 1.8 F 2 I QE I real Calculated Considering the same Ffactor I,O

SWM UD, April 2004Nadia Tonello, MPI 17 Check inner-outer pixels: conversion factors Inner pixels: 165 FADCcounts Outer pixels: 150 FADCcounts n  I n peI = n  I n ADCI n peI n ADCI = 0.78 n  O n ADCO = n  O n peO n ADCO = 3.46 ~ 3.5 photons/ FADC count ~ 0.8 photons/ FADC count

SWM UD, April 2004Nadia Tonello, MPI 18 Check inner-outer pixels: pedestal RMS Inner pixels: 7 FADCcounts per slice Outer pixels: 5 FADCcounts per slice n  I = 7 = 5.5 n  O n ADCO n  O = 5 = 17.3 ~ 17 photons/ FADC slice ~ 6 photons/ FADC slice n  I n ADCI

SWM UD, April 2004Nadia Tonello, MPI 19 Conclusions In Munich we calibrate using the Ffactor method and flat fielding Our checks pointed out that the results are consistent

SWM UD, April 2004Nadia Tonello, MPI 20 How we checked it: Q in Mean charge for the inner pixels excluding cosmics and bad pixels ~160 FADC counts channel Hardware problems?