Calibration Munich group version Checks SWM UD April

Calibration Munich group version Checks SWM UD, April 2004 Nadia Tonello, MPI

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 2004 Nadia Tonello, MPI 2

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 2004 Nadia Tonello, MPI 3

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

How we calibrate. . . 2. Calculation of calibration factors using signal estracted from calibration runs by MCalibration. Charge. Calc etc. ~23 photoelectrons for inner pixel area SWM UD, April 2004 Nadia Tonello, MPI 5

How we calibrate. . . 3. NEW: Flat fielding of the number of photons in the calibration-run. ~135 photons for inner pixel area SWM UD, April 2004 Nadia Tonello, MPI 6

How we calibrate. . . NEW calibration factors: multiply the previously calculated with the correction factor flat fielding. ~ 3. 5 photons/ FADC count ~ 0. 8 photons/ FADC count SWM UD, April 2004 Nadia Tonello, MPI 7

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

How we checked it: New Class to calculate the conversion factors with the Ffactor method (used instead of MCalibration. Charge. Calc etc. ) Qin ci Mean charge for the inner pixels excluding cosmics and bad pixels Correction factor to flat field the charges s. Qm distribution obtained summing all the charge distributions of the pixels after flat fielding sred from the mean corrected pedestal SWM UD, April 2004 RMS Nadia Tonello, MPI 9

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

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

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

Mean number of photoelectrons Nphel = (Qin 2/ s 2 red) F 2 where F 2= 1. 335 (as in MCalibration. Charge. Calc) Conversion factors: (Ph/FADCcount)i = Nphel ci / Qin /phxpe where phxpe = 0. 18 (as in MCalibration. Charge. Calc) SWM UD, April 2004 Nadia Tonello, MPI 13

Result: Calibration factors in agreement ~ 3. 5 photons/ FADC count ~ 0. 8 photons/ FADC count SWM UD, April 2004 Nadia Tonello, MPI 14

Check inner-outer pixels: pe Inner pixels: 23 pe/area Outer pixels: 13 pe/area npe. I= 1. 8 npe. O npe = 0. 18 ng SWM UD, April 2004 ng. I 1 = = 5. 6 npe. I 0. 18 ng. O 1. 8 = 10 = npe. O 0. 18 ng. I = 0. 25 ng. O Nadia Tonello, MPI 15

Check inner-outer pixels: F 2/QE npe. I =23 npe. O =13 · 4 = 52 Calculated Considering the same Ffactor I, O npe. O FI 2 npe. O = 2 npe. I FO npe. I npe. O = 2. 22 npe. I real ng. O npe. O QEI FO 2 npe. O = = = 4 ng. I QEO npe. I QEO FI 2 npe. I F 2 O F 2 I = 1. 8 QEO QEI SWM UD, April 2004 Nadia Tonello, MPI 16

Check inner-outer pixels: conversion factors Inner pixels: 165 FADCcounts Outer pixels: 150 FADCcounts ~ 3. 5 photons/ FADC count ng. I npe. I = = 0. 78 n. ADCI npe. I n. ADCI ng. O npe. O = = 3. 46 n. ADCO npe. O n. ADCO ~ 0. 8 photons/ FADC count SWM UD, April 2004 Nadia Tonello, MPI 17

Check inner-outer pixels: pedestal RMS Inner pixels: 7 FADCcounts per slice Outer pixels: 5 FADCcounts per slice ~ 17 photons/ FADC slice ng. I = 7 = 5. 5 n. ADCI ng. O = 5 = 17. 3 n. ADCO ~ 6 photons/ FADC slice SWM UD, April 2004 Nadia Tonello, MPI 18

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