Electron high energy calibration

1
Electron high energy calibration
Robert Zitoun Stony Brook and LAPP CAT Force
Meeting May 13, 2003
2
Monte Carlo Energy Resolution

• Found 3 resolution for 50 GeV electrons (3.1
  w/o geo correction)
• i.e.
• Still have to look at Z Monte Carlo. Volker says
  2.8

Run I Eta corrections p13
S 0.15 0.199 0.008
N 0.16 0.42 0.08
C 0.003 0.0076 0.0014
3
Data

• p13.05 p13.06 r13.06
• certified CC em objects
• pT gt25 GeV
• out of module boundaries
• one cluster matched to a track
• Fit it with a Breit-Wigner function M 90.2
  0.1 GeV
• convoluted with a gaussian s 3.6 0.1 GeV
• BW(MZ, G0 MZ/M0) N(0, s) bkg s/M 4.0
• MZ free, s is the resolution far from 22.8
• M0 and G0 are the PDG values
• allows for scale indeterminacy

4
Step by Step Corrections

• Take Cal DataChunk
• Get back to raw ADC
• Apply reco corrections one by one

MZ/GeV sZ/GeV sZ/MZ
raw ADC 81.5 3.6 4.4
non linearity 86.7 3.7 4.3
gain correction 86.6 3.6 4.2
scale 86.5 3.6 4.1
geometric 90.2 3.6 4.0
5
Better Calibration

• Sampling not done at maximum (1 effect)
• Chan to chan variation different in calibration
  and physics (1)

calibration
physics
4 channels same h, j in layer 3
6
Results with Better Calibration
MZ/GeV sZ/GeV sZ/MZ
reco 90.2 3.6 4.00.1
calibration timing 90.2 3.6 4.0
physics timing 90.2 3.6 3.9
amplitude 90.0 3.4 3.8
7
Variations

• Fit calweights to minimize Z width
• 1.040.004 0.780.016 1.050.005
  1.020.01 0.480.06
• highly correlated corr(1,2) -0.9 corr(2, 3)
  -0.8
• use 2 series of calweights for hlt0.5 or gt0.5
• on the 4 CC pulser amplitudes
• fit 4 parameters to minimize Z resolution
• 1.005, 0.997, 1.000, 1.007
• Make 10 h slices and fit 10 normalization
  constants
• 1.00 within lt1

before 90.0 3.4 3.80.1
after tuning weights 90.4 3.3 3.7
use 2 calweights 90.4 3.3 3.7
pulser amplitudes 90.2 3.4 3.8
10 h slices 90.4 3.3 3.7
8
Shower Size

• Volkers suggestion j width agrees with MC but
  not z

M s resol evt
all 90.4 3.49 3.86 3332
szlt8 89.7 3.28 3.65 645
8ltszlt10 90.2 3.50 3.88 608
10ltszlt14 90.8 3.73 4.10 773
14ltszlt30 90.7 3.39 3.72 576
M s resol evt
all 90.4 3.49 3.86 3332
sjlt7 90.4 3.07 3.39 351
7ltsjlt9 90.4 3.43 3.79 667
9ltsjlt11 90.6 3.71 4.10 565
11ltsjlt20 89.8 3.73 4.19 569
9
Module Boundaries

• CC calorimeter made of 32 wedges Dj 0.2
• loss of clusters (?)
• loss of energy (no plot)
• Oleg Kouznetsov showed that
• approx. gaussian energy loss
• with j away from crack
• amplitude 20 s 15 mrad

10
Module Boundaries (2)
MZ/GeV sZ/GeV sZ/MZ
90.4 3.3 3.7
djgt0.06 91.0 2.7 3.0
djlt0.04 87.3 2.9 3.3
Oleg 91.1 3.1 3.4
ampl 21 s 15mrad 91.3 3.0 3.30.13
not yet 22.8 but more to gain?
s 3.3