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Abnormal distribution [message #14377]

Mon, 21 January 2013 18:45

Jifeng Hu
Messages: 31
Registered: October 2012

continuous participant

From: *physik.uni-giessen.de

In this simulation, a box generator was used to shoot three 1GeV energy photons. Then their energy was reconstructed (E_{rec}, and compared to the energy in Monto Carlo truth (E_{truth}).

please see the plot in the attachment.

The X-axis shows the polar angle in unit rad, the Y axis shows the energy difference (E_{rec}-E_{truth}) in unit GeV.

We can find,
a) the Shashlyk calorimeter has a worse resolution, but a longer right-side tail, it implies a incorrect reconstruction in EMC cluster or bump.
b) for the intersection between forward calorimeter and shashlyk calorimeter, still a longer right-side tail exists.

c) barrel calorimeter looks good, a left-side tail arises from the energy leak in crystal and energy loss before hitting crystals.

d) for the intersection between barrel and backward, there exists a large gap, but abnormal reconstruction near theta value 2.5.

e) energy reconstruction near the edge of backward calorimeter need more correction.

What are your opinions?
The energy reconstruction determines the photon detection efficiency.

Attachment: energy_vs_theta.eps
(Size: 462.49KB, Downloaded 402 times)

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Re: Abnormal distribution [message #14378 is a reply to message #14377]

Tue, 22 January 2013 10:59

Dima Melnychuk
Messages: 213
Registered: April 2004
Location: National Centre for Nucle...

first-grade participant

From: *fuw.edu.pl

Hi Jifeng,

Could you clarify which reconstructed cluster energy do you use, i.e.

PndEmcCluster::GetEnergyCorrected()

or from

PndEmcClusterCalibrator::Energy()

May be just better post your analysis macro here.

Dima

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Re: Abnormal distribution [message #14379 is a reply to message #14378]

Tue, 22 January 2013 11:40

Jifeng Hu
Messages: 31
Registered: October 2012

continuous participant

From: *physik.uni-giessen.de

Here I show the codes slice,
PndEmcBump* theHit = (PndEmcBump*) fRecoHitArray->At(HitIndex1);
fEnergy1 = theHit->energy(); // E1
fEnergy1C = theHit->GetEnergyCorrected()/1.009; //E1C
PndEmcCorrection* theCorr = (PndEmcCorrection*)fCluCorrArray->At(HitIndex1);
fEnergy1CC = theCorr->EnergyCorrPhoton(); //E1CC

since the peak energy provided by theHit->GetEnergyCorrected() has a shift, temporarily I made a further correction by a factor 1.009.

Attachment eps file shows the difference between
E1C-E1, E1CC-E1, and E1CC-E1C.

PndEmcClusterAna class is used to save information from PndEmcBump.
PndEmcMcTruthWriter class is used to save information from PncMCTrack.

best regards.

Attachment: 3energy_diff.eps
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Attachment: 3energy.eps
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Attachment: PndEmcClusterAna.cxx
(Size: 18.88KB, Downloaded 280 times)
Attachment: PndEmcClusterAna.h
(Size: 3.30KB, Downloaded 231 times)
Attachment: PndEmcMcTruthWriter.cxx
(Size: 22.24KB, Downloaded 242 times)
Attachment: PndEmcMcTruthWriter.h
(Size: 3.75KB, Downloaded 259 times)

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Re: Abnormal distribution [message #14381 is a reply to message #14379]

Tue, 22 January 2013 12:55

Dima Melnychuk
Messages: 213
Registered: April 2004
Location: National Centre for Nucle...

first-grade participant

From: *fuw.edu.pl

The first approach for energy correction

theHit->GetEnergyCorrected()

is obsolete and should be in principle removed.

What I personally used/implemented is the class
PndEmcClusterCalibrator(method),
which for
method=1 uses the same approach, but with corrected parametrization
and for
method=2 uses the same approach as in PndEmcCorrection class
but with recalculated histograms

See my old post ( https://forum.gsi.de/index.php?t=tree&th=3457&start=0&rid=78 &S=6d7276e6f9612e28feff1e110f9d321d) for details.

Example how to use it is in
/macro/emc/dedicated/EnergyPosCorrection/emc_correction_QA.C

But in short

PndEmcAbsClusterCalibrator * calibrator1= PndEmcClusterCalibrator::MakeEmcClusterCalibrator(1);
PndEmcAbsClusterCalibrator * calibrator2= PndEmcClusterCalibrator::MakeEmcClusterCalibrator(2);

PndEmcCluster *cluster=(PndEmcCluster*)cluster_array->At(i);

Double_t energy=cluster->energy();
Double_t energyC1 = calibrator1->Energy(cluster);
Double_t energyC2 = calibrator2->Energy(cluster);

Method 1 and 2 give in principle close results.

Could you recalculate you initial plot with these corrections?

Dima

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Re: Abnormal distribution [message #14387 is a reply to message #14381]

Wed, 23 January 2013 10:38

Jifeng Hu
Messages: 31
Registered: October 2012

continuous participant

From: *physik.uni-giessen.de

Hi, Dima,
With your suggestion, some new plots are got. you can find
them in the eps file attached.

here lists my brief code slice.

PndEmcAbsClusterCalibrator * calibrator1= PndEmcClusterCalibrator::MakeEmcClusterCalibrator(1);
PndEmcAbsClusterCalibrator * calibrator2= PndEmcClusterCalibrator::MakeEmcClusterCalibrator(2);

PndEmcBump* theHit = (PndEmcBump*) fRecoHitArray->At(HitIndex1);
fEnergy1 = theHit->energy();
fEnergy1C = calibrator1->Energy(theHit);
fEnergy1CC = calibrator2->Energy(theHit);

conclusions:
a> calibration still needs further improvement for crystals near backward endcap edges.
b> calibrator2 looks better for intersection between forward and barrel calorimeter, but a little problem in theta ranges near value 2.5.

However, results looks much better.
Thanks for your correction.

best regards,

Jifeng Hu

Attachment: energy_cor.eps
(Size: 210.35KB, Downloaded 353 times)

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