Status of calibration:
Event
selection.
Comparison of
different Calibration sets
Study of
the linearity.
Event selection.
Tagger Energy distributions
Snake1
(left) and snake2(right) tagger energy
Tagger timing
All
tagger timing (left) and zoom tagger timing (right) after selection
Swapped channels and T9 time.
T9 timing
problem (left) and swapped channels (right).
Final cuts:
- tagger time window +/- 15 ns
- energy range 4-4.75 GeV
- Cluster energy is inside 0.2 - 3 of
Tagger energy. The interval is different for different iterations :
- +/-0.06 for Glass and +/-0.03 for PWO
for final Matrix Inversion Iterations
- single possible combination in event
Comparison
of different Calibration sets
Comparison
Iteration and Matrix Inversion methods
Number
of possible different cells: 1728 (all cells) - 12(central cells)
-3(holes) = 1713.
1.
Comparison of iteration and matrix inversion method for snake2 for all
cells (left) and for PWO only (right)
The average
difference is less than 0.03%, RMS is less, than 0.2%. Only one cell
differs more than 2% and two other cells at about 1%. The agreement is
perfect.
Comparison between 2 Matrix Inversion
methods
Method 1: Initial coefficients are received
from Iteration method
Method 2: Initial coefficients are 1 for all cells (except central -
already calibrated).
The difference is presented on the next Figure. There are no any real
difference at all.
Comparison with previous (Ilya) calibration
Difference
for PWO (left) and glass (right) for snake2 between this and
Ilya calibrations:
Small
difference for PWO is explained by different calibration region
and non-linearity coefficients.
Additional difference for glass is mainly explained by leakage
procedure.
The difference for glass without edges is presented below:
Few
modules to the right are row and column close to PWO.
The
difference can not explain low pi0 mass for Glass (Dustin
presentation). Non-linearity or something else should be added
Comparison of Snake1 and Snake2 constants.
Difference
(first-last) for all channels (left) and for glass only(right)
Looks the same as Dustin presented for Ilya
calibration.
Left tail is from PWO cells:
The difference for all PWO (left) and for
central 10x10 matrix:
Central
crystals really changed (affected by irradiation).
And the difference is even larger between calibrations.
The difference is important for 14x14 matrix
(left) and is very small outside the region (right)
Really
good outside 14x14 region.
0.7% difference may be explained by many factors (change
of the temperature for example by 0.3 C).
Main Conclusion: The calibration of central
cells during data taking is really important.
Study
of the linearity.
Method.
Load received coefficients and
find the dependence of ratio E_cluster/E_tagger on tagger energy or
e_counter_id.
Resolutions
for PWO (left) and Glass (right) for ALL cells and events:
Linearity for PWO (top) and glass (bottom)
on energy.
The same pictures, but for e_counter_id.
Structures
are in the same place and approximately the same amplitude for Glass
and PWO (see
zoom pictures)
Examples
of the fitting procedure for different e_counter_id's for
Glass(e_counter_id=10,
310,
510,
710)
and PWO (e_counter_id=20,
520,
720).
The result for snake2 calibration is exactly the same:
Conclusions:
- I can not believe that this behavior is
accidental.
- The detector can not explain the behavior
(all counters and the same
for Glass and PWO and different calibrations). Something strange in
tagger reconstruction?
- Stepan difference is clearly seen.
I
propose to call tagger experts and understand this function.
We have finally to understand our
tagger reconstruction procedure.