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Reconstructed photon energy for single photon event [message #18200]

Tue, 12 May 2015 12:03

kamalpdutta
Messages: 30
Registered: December 2014
Location: Guwahati, India

continuous participant

From: 14.139.207*

Dear All,

I have generated single photon events for energy 1 GeV using box generator. Anyone please tell me how should I calculate the reconstructed photon energy for each event. I have tried and sum-up all the energy of all secondary particles for each event. But it gives me unexpected value having mean at nearly 4 GeV.

regards
Embarassed

Embarassed

Kamal Dutta
Gauhati University

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Re: Reconstructed photon energy for single photon event [message #18201 is a reply to message #18200]

Tue, 12 May 2015 12:19

StefanoSpataro
Messages: 2736
Registered: June 2005
Location: Torino

first-grade participant

From: *ip71.fastwebnet.it

PndEmcCluster::energy() from the digi file, or PndPidNeutralCand::GetEmcRawEnergy() (for raw energy) ::GetEmcCalEnergy() (for calibrated energy) if you start from the pid file.

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Re: Reconstructed photon energy for single photon event [message #18203 is a reply to message #18201]

Tue, 12 May 2015 14:13

kamalpdutta
Messages: 30
Registered: December 2014
Location: Guwahati, India

continuous participant

From: 14.139.207*

Thanks. But I do not understand why its 259 entries in PndEmcCluster::energy() for 100 primary photons. It is like I have 259 EMC clusters for 100 primary photons. Can you help me get it ?

regards
Kamal Dutta

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Re: Reconstructed photon energy for single photon event [message #18204 is a reply to message #18203]

Tue, 12 May 2015 14:19

StefanoSpataro
Messages: 2736
Registered: June 2005
Location: Torino

first-grade participant

From: *ip71.fastwebnet.it

The others are secondaries. You can select GetMcIndex()==0 to have only the primaries (even if you should see still some split-off).

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Re: Reconstructed photon energy for single photon event [message #18205 is a reply to message #18204]

Tue, 12 May 2015 14:31

kamalpdutta
Messages: 30
Registered: December 2014
Location: Guwahati, India

continuous participant

From: 14.139.207*

Hi, the problem is, if I am getting more reconstructed photons than generated, how can I relate them. I mean, If I want to have the energy difference between the generated i,e 1 GeV and reconstructed, how it is possible ? As per my knowledge, if a single photon hits the EMC crystal, the digitized output should give a single cluster which will estimate the energy of the primary photon. Thus for 100 primary photons, it should have 100 emc cluster and their energy accordingly. Please correct me if I am wrong.

regards
Kamal Dutta

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Re: Reconstructed photon energy for single photon event [message #18206 is a reply to message #18205]

Tue, 12 May 2015 14:33

StefanoSpataro
Messages: 2736
Registered: June 2005
Location: Torino

first-grade participant

From: *ip71.fastwebnet.it

Again, one photon interacts with materials and form different signals in the emc, then you can have more than 1 clusters. if you select the mc index you should isolare your primary photon.

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Re: Reconstructed photon energy for single photon event [message #18207 is a reply to message #18206]

Tue, 12 May 2015 14:46

kamalpdutta
Messages: 30
Registered: December 2014
Location: Guwahati, India

continuous participant

From: 14.139.207*

Thanks, Where can I get GetMcIndex() ?

regards
Kamal Dutta

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Re: Reconstructed photon energy for single photon event [message #18208 is a reply to message #18207]

Tue, 12 May 2015 14:47

StefanoSpataro
Messages: 2736
Registered: June 2005
Location: Torino

first-grade participant

From: *ip71.fastwebnet.it

PidNeutralCand::GetMcIndex()

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Re: Reconstructed photon energy for single photon event [message #18215 is a reply to message #18208]

Wed, 13 May 2015 08:47

kamalpdutta
Messages: 30
Registered: December 2014
Location: Guwahati, India

continuous participant

From: 14.139.207*

Thanks a lot. I have written a piece of code to access PndPidNeutralCand::GetEmcCalEnergy(), but getting error. I have attached both the code and errors. Please have a look.

regards

Attachment: gam_conv_pid.C
(Size: 1.27KB, Downloaded 302 times)
Attachment: errors
(Size: 0.52KB, Downloaded 298 times)

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Re: Reconstructed photon energy for single photon event [message #18216 is a reply to message #18215]

Wed, 13 May 2015 09:08

StefanoSpataro
Messages: 2736
Registered: June 2005
Location: Torino

first-grade participant

From: 91.253.173*

punk is a PndPidCandidate named "PidNeutralCand".

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Re: Reconstructed photon energy for single photon event [message #18219 is a reply to message #18216]

Wed, 13 May 2015 12:16

kamalpdutta
Messages: 30
Registered: December 2014
Location: Guwahati, India

continuous participant

From: 14.139.207*

Hi Stefano,

I corrected according to you. Please look at the code. I have also attached the reconstructed photon energy plot. I am not understand how to accept it, as reconstructed photon energy of generated energy 1 GeV. It has 202 events and energy more that 1 GeV too. But the generated events are of 1GeV and 100 events.

Attachment: gam_conv_pid.C
(Size: 1.31KB, Downloaded 278 times)
Attachment: gam_e.eps
(Size: 7.68KB, Downloaded 317 times)

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Re: Reconstructed photon energy for single photon event [message #18220 is a reply to message #18219]

Wed, 13 May 2015 12:20

StefanoSpataro
Messages: 2736
Registered: June 2005
Location: Torino

first-grade participant

From: *to.infn.it

Again:

for (Int_t k = 0; k < ar_entries; k++){
      punkt = (PndPidCandidate*) hit_array->At(k);
->   if (punkt->GetMcIndex()!=0) continue;

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Re: Reconstructed photon energy for single photon event [message #18221 is a reply to message #18220]

Wed, 13 May 2015 12:25

kamalpdutta
Messages: 30
Registered: December 2014
Location: Guwahati, India

continuous participant

From: 14.139.207*

It gives the same output.

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Re: Reconstructed photon energy for single photon event [message #18222 is a reply to message #18221]

Wed, 13 May 2015 12:32

StefanoSpataro
Messages: 2736
Registered: June 2005
Location: Torino

first-grade participant

From: *to.infn.it

I suppose not exactly the same.
In any case, the peak around 1 is your primary photon while the low energetic part comes from secondries and split-off. You can get rid of it with a simple energy cut. The position of the peak depends on the calibration.

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Re: Reconstructed photon energy for single photon event [message #18223 is a reply to message #18222]

Wed, 13 May 2015 12:43

kamalpdutta
Messages: 30
Registered: December 2014
Location: Guwahati, India

continuous participant

From: 14.139.207*

But I am worried about the part above 1 GeV. How to estimate these values. If I want to estimate reconstructed photon energy for each of the primary photon and its start vertex of EM shower, how it is possible in this situation. The start vertex I calculated for 100 events using PndMCIndex. On the other hand, I got 202 reconstructed photon events from PndPidCandidate. It really puzzled me.

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