calibration munich group version checks. swm ud, april 2004nadia tonello, mpi 2 idea calibration...

CalibrationCalibration

Munich group versionChecks

SWM UD, April 2004 Nadia Tonello, MPI 2

IdeaIdeaCalibration runs:

same number of photons in all PMsFlat fielding:

same pixels output from calibration runsCalibration methods:

Ffactor method (relative calibration)Blind-pixel method (absolute calibration)

We did consistency checks


Jan –Feb 2004Jan –Feb 2004Which method for calibration?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 checknew independent class to compare the

resulting conversion factors


How we calibrate...How we calibrate...Same scheme as calibcalcphotons.C

1. Extraction of Pedestals from pedestal runs in FADCcounts using MPedCalcPedRun


How we calibrate...How we calibrate...2. Calculation of calibration factors

using signal estracted from calibration runs by MCalibrationChargeCalc etc.

~23 photoelectrons for inner pixel area


How we calibrate...How we calibrate...3. NEW: Flat fielding of the number of

photons in the calibration-run.

~135 photons for inner pixel area


How we calibrate...How we calibrate... NEW calibration factors: multiply the

previously calculated with the correction factor for flat fielding.

~ 0.8 photons/ FADC count



How we calibrate...How we calibrate...4.Calibration of data and pedestals

using MCalibrate Data


How we checked it:How we checked it:New Class to calculate the conversion factors with the Ffactor method (used instead of MCalibrationChargeCalc etc.)

Qin Mean charge for the inner pixels

excluding cosmics and bad pixels ci Correction factor to flat field the

charges

Qm distribution obtained summing all the charge distributions of the

pixels after flat fielding

red from the mean corrected pedestal RMS


How we checked it:How we checked it:Qin Mean charge for the inner pixels

excluding cosmics and bad pixels

~160 FADC counts

channel channel


How we checked it:How we checked it:ci Correction factor to flat field the

charges

~160 FADC counts

channel channel


How we checked it:How we checked it:Qm distribution obtained summing all the charge distributions of the pixels after flat fielding

Qm~43 counts


Mean number of photoelectrons

Nphel = (Qin2/ 2

red) F2

where F2= 1.335 (as in MCalibrationChargeCalc)

Conversion factors: (Ph/FADCcount)i = Nphel ci / Qin /phxpe

where phxpe = 0.18 (as in MCalibrationChargeCalc)


Result:Result:Calibration factors in agreement




Check inner-outer pixels: peInner pixels: 23 pe/areaOuter pixels: 13 pe/area

npeI= 1.8

npeO

npe = 0.18

n

nI

npeI

10.18

= 5.6=

nO

npeO

= 1.80.18

= 10

nI = 0.25 nO


Check inner-outer pixels: F2/QEnpeI =23

npeO =13 · 4 = 52

nO

nI

npeO

npeI

= 2.22

npeO

npeI

=FI2

FO2

nnpeO

npeI

=nnpeO

QEO

QEI

npeI

= QEI

QEO

FO2

FI2

npeO

npeI

= 4

F2O

QEO

= 1.8F2I

QEI

real

CalculatedConsidering the same Ffactor I,O


Check inner-outer pixels: conversion factors

Inner pixels: 165 FADCcountsOuter pixels: 150 FADCcounts

nI

npeI

=nI

nADCI

npeI

nADCI

= 0.78

nO

nADCO

=nO

npe

O

npeO

nADCO

= 3.46 ~ 3.5 photons/ FADC count



Check inner-outer pixels: pedestal RMS

Inner pixels: 7 FADCcounts per sliceOuter pixels: 5 FADCcounts per slice

nI = 7 = 5.5

nO

nADCO

nO = 5 = 17.3 ~ 17 photons/ FADC slice

~ 6 photons/ FADC slice

nI

nADCI


ConclusionsConclusions In Munich we calibrate using the

Ffactor method and flat fielding Our checks pointed out that the

results are consistent

calibration munich group version checks. swm ud, april 2004nadia tonello, mpi 2 idea calibration...

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