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Calibration

Calibration. Munich group version Checks. 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)

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Calibration

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  1. Calibration Munich group version Checks

  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 Nadia Tonello, MPI

  3. Jan –Feb 2004Which 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 Nadia Tonello, MPI

  4. How we calibrate...Same scheme as calibcalcphotons.C 1. Extraction of Pedestalsfrom pedestal runs in FADCcounts using MPedCalcPedRun Nadia Tonello, MPI

  5. How we calibrate... 2. Calculation of calibration factorsusing signal estracted from calibration runs by MCalibrationChargeCalc etc. ~23 photoelectrons for inner pixel area Nadia Tonello, MPI

  6. How we calibrate... 3. NEW: Flat fieldingof the number of photons in the calibration-run. ~135 photons for inner pixel area Nadia Tonello, MPI

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

  8. How we calibrate... 4.Calibration of data and pedestalsusing MCalibrate Data Nadia Tonello, MPI

  9. How we checked it:New Class to calculate the conversion factors with the Ffactor method(used instead of MCalibrationChargeCalc etc.) QinMean charge for the inner pixels excluding cosmics and bad pixels ciCorrection factor to flat field the charges sQmdistribution obtained summing all the charge distributions of the pixels after flat fielding sredfrom the mean corrected pedestal RMS Nadia Tonello, MPI

  10. How we checked it: QinMean charge for the inner pixels excluding cosmics and bad pixels ~160 FADC counts channel channel Nadia Tonello, MPI

  11. How we checked it: ciCorrection factor to flat field the charges ~160 FADC counts channel channel Nadia Tonello, MPI

  12. How we checked it: sQmdistribution obtained summing all the charge distributions of the pixels after flat fielding sQm~43 counts Nadia Tonello, MPI

  13. Mean number of photoelectrons Nphel = (Qin2/ s2red)F2 where F2= 1.335 (as in MCalibrationChargeCalc) Conversion factors: (Ph/FADCcount)i = Nphel ci / Qin /phxpe where phxpe= 0.18 (as in MCalibrationChargeCalc) Nadia Tonello, MPI

  14. Result: Calibration factors in agreement ~ 3.5 photons/ FADC count ~ 0.8 photons/ FADC count Nadia Tonello, MPI

  15. Check inner-outer pixels: pe Inner pixels: 23 pe/area Outer pixels: 13 pe/area npeI= 1.8 npeO npe= 0.18 ng ngI npeI 1 0.18 = = 5.6 ngO npeO 1.8 0.18 = 10 = ngI = 0.25 ngO Nadia Tonello, MPI

  16. Check inner-outer pixels: F2/QE npeO npeI Calculated Considering the same Ffactor I,O = 2.22 npeI =23 npeO =13 · 4 = 52 npeO npeI npeO npeI FI2 FO2 real = ngO ngI npeO QEO QEI npeI QEI QEO npeO npeI FO2 FI2 = = = 4 F2O QEO F2I QEI = 1.8 Nadia Tonello, MPI

  17. Check inner-outer pixels: conversion factors Inner pixels: 165 FADCcounts Outer pixels: 150 FADCcounts ngI nADCI ngI npeI npeI nADCI = = 0.78 ~ 3.5 photons/ FADC count ~ 0.8 photons/ FADC count ngO nADCO ngO npeO npeO nADCO = = 3.46 Nadia Tonello, MPI

  18. Check inner-outer pixels: pedestal RMS Inner pixels: 7 FADCcounts per slice Outer pixels: 5 FADCcounts per slice ngI nADCI ngI = 7 = 5.5 ngO nADCO ngO = 5 = 17.3 ~ 17 photons/ FADC slice ~ 6 photons/ FADC slice Nadia Tonello, MPI

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

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