[Gate-users] optical and traditional Singles.

Uwe Pietrzyk u.pietrzyk at fz-juelich.de
Sun May 24 21:49:26 CEST 2009

Dear  Esteban,

recently one of our students came across the same problem / question.
I looked into it and found the following concept, which I hope is  
(and experts, please, should correct me!!!).
Unfortunately, I could not find any example root module for a combined
analysis of standard and optical photons.

All remarks refer to gate_v4.0.0!!
Using the "opticaladder" adds the optical photons to the standard and
does not replace the standard information! For a comprehensive
analysis it is also recommended to run the standard "analysis"
and not the "fastanalysis".
The information concerning the gamma and the optical photons
created by the incident gamma through photoeffect, comptoneffect, ...
are stored in root files under

gamma  >>  singles-tree
optical photons  >>  hits-tree

and also in the singles and hits ascii files, once you have switched
on the ascii output option.

Note, that the acscii files can get quite large, especially the "hits".
For my tests I modified the materials.xml file reducing the number
of photons per MeV in LSO from 26000 to 1000.

In the attached file you find a simple example for a root source code
reading root file and checking its contents.
I also included the ascii files for comparison.

Maybe this is helpful for you. I cannot warrant, that my understanding
of handling the optical photons in GATE is correct, but it looked
consistent to me.

Kind regards,

Uwe Pietrzyk

On 20.05.2009, at 15:52, venialgo at cae.cnea.gov.ar wrote:

> Hello Gate Users
> I'm simulating the optical photons, I've defined a continuous  
> crystal of
> NaI(Tl) coupled to an array of 6x8 PMTs. I have defined also the  
> optical
> adder and I have the information of the amount of light received in  
> each
> PMT, but also I want to know the position of the singles calculated  
> as the
> energy-weighted centroid of the different hit positions produced by  
> the
> gamma interaction into the crystal.
> In the section 12.4 of the Gate Users guide v3.1.2 says it's to  
> possible
> to create two chains in parallel one containing the traditional  
> singles
> and one containing the singles generated by the optical photons.
> In the macro I've just written:
> /gate/digitizer/Singles/insert adder
> /gate/digitizer/Singles/insert opticaladder
> And the gateSingles.dat is completely empty.
> but, when I comment out the optical adder ..
> /gate/digitizer/Singles/insert adder
> # /gate/digitizer/Singles/insert opticaladder
> The  gateSingles.dat has the information of the traditional singles.
> even more,  when I comment out the adder
> # /gate/digitizer/Singles/insert adder
> /gate/digitizer/Singles/insert opticaladder
> The  gateSingles.dat has the information of the optical singles.
> And finally I ran the simulation 7 days with the optical adder  
> commented
> out, and 7 days more with the adder commented out. Obviously using the
> same seed file in each run.
> I want simulate only once, with two digitizer chains in parallel,  
> which
> takes only 7 days, if it's possible off course.
> P.S: I'm not using the last version of Gate, My configuration is :
> Plataforma/Gate:  ROOT 5.14 / CLHEP / GEANT 4.9.0 (PATCH) /  
> 3.1.2                                            O.S.: Debian 4.0r1  
> AMD64
> Kernel 2.6.24-etchnhalf.1-amd64
> Thanks for your help,
> Bye, Esteban Venialgo
> _______________________________________________
> Gate-users mailing list
> Gate-users at lists.healthgrid.org
> http://lists.healthgrid.org/mailman/listinfo/gate-users

Prof. Dr. Uwe Pietrzyk
Institut für Neurowissenschaften und Medizin / INM-1
Forschungszentrum Jülich GmbH
52425 Jülich
Tel: +49-2461-61 4763
Fax: +49-2461-61 2820 + 8229
Mobil: +49-162-103-4871
eMail: U.Pietrzyk at fz-juelich.de
Bergische Universität Wuppertal
Fachbereich C - Physik / D.08.01
Gaußstr. 20
42097 Wuppertal
Tel: +49-(0)202-439-3523
Fax: +49-(0)202-439-2811
eMail: Uwe.Pietrzyk at physik.uni-wuppertal.de

Forschungszentrum Jülich GmbH
52425 Jülich

Sitz der Gesellschaft: Jülich
Eingetragen im Handelsregister des Amtsgerichts Düren Nr. HR B 3498
Vorsitzende des Aufsichtsrats: MinDir'in Bärbel Brumme-Bothe
Geschäftsführung: Prof. Dr. Achim Bachem (Vorsitzender),
Dr. Ulrich Krafft (stellv. Vorsitzender), Prof. Dr. Harald Bolt,
Prof. Dr. Sebastian M. Schmidt

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