[Gate-users] Question related to Gate

[David Sarrut]

Hello,

Disclaimer: I am not used to tracking of optical photons, probably more
experienced users can bring more advice.

However, conventional PET simulation with GATE does NOT track optical
photons. In the scintillator crystal, the deposited energy is considered as
a surrogate of the number of optical photons (that are not produced, not
tracked), eventually weighted by some efficiency factor. If you plan a more
deep simulation that really tracks optical photons in such a large system
than a PET, be prepare to face enormous computation time. Simulation with
optical photons is, to my knowledge, limited to the characterisation of one
single detector.

HTH,
David

On Fri, Nov 1, 2019 at 3:25 PM Christodoulou, Theodoros (2017) <
Theodoros.Christodoulou.2017 at live.rhul.ac.uk> wrote:

> Dear  D.Sarrut,
>
> I have a question related to GATE. I want to simulate a PET scanner but
> instead of using the standard scintillation mediums (LSO e.t.c) I want to
> use liquid Argon. Therefore I have to attach the scintillation properties
> of liquid argon to G4_lAr material.
>
> Moreover, the vessel which will contain liquid argon will be
> stainless_steel and I want to add a reflective coating on it so the
> scintillation photons will bounce inside the vessel and then detected by
> the sensitive detector.
>
> Can Gate do this thing? I have managed to do that in a Geant4 simulation I
> wrote for a single cell but I want to use Gate for a complete detector.
>
> Best
> Theo
>
> Example of G4 code I wrote and tested for the two question I have above.
> /Materials
>     //Liquid Argon
>     G4NistManager *mat = G4NistManager::Instance();
>     G4Material *LAr = mat->FindOrBuildMaterial("G4_lAr") ;
> //LAr properties
>     G4double lar_Energy[]= { 20.60*eV, 15.5*eV, 11.92*eV,11.2*eV,10.87*eV,
> 10.69*eV,10.5*eV,10.3*eV,10.13*eV,
>                              9.97*eV,9.81*eV,9.73*eV,9.66*eV,9.58*eV,9.51*
> eV,9.44*eV,9.36*eV,9.22*eV,9.09*eV,8.96*eV,
>                              8.83*eV,8.70*eV,8.52*eV,8.35*eV,8.13*eV,7.02*
> eV,1.55*eV};
>
> G4MaterialPropertiesTable *LAr_mt = new G4MaterialPropertiesTable();
>     LAr_mt->AddProperty("FASTCOMPONENT", lar_Energy, lar_fSCINT, larnum);
>     LAr_mt->AddProperty("SLOWCOMPONENT", lar_Energy, lar_sSCINT, larnum);
>     LAr_mt->AddProperty("RINDEX",        lar_Energy, lar_RIND,  larnum);
>     LAr_mt->AddProperty("ABSLENGTH",     lar_Energy, lar_ABSL,  larnum);
>     LAr_mt->AddConstProperty("SCINTILLATIONYIELD",40./keV);
>     LAr_mt->AddConstProperty("RESOLUTIONSCALE",0.11);
>     LAr_mt->AddConstProperty("FASTTIMECONSTANT",6.*ns);
>     LAr_mt->AddConstProperty("SLOWTIMECONSTANT",1600*ns);
>     LAr_mt->AddConstProperty("YIELDRATIO",0.67);
>     LAr->SetMaterialPropertiesTable(LAr_mt);
>
> For stainless steel, I created a reflective surface between steel and LAr
>
> G4OpticalSurface* OpLarSurface = new G4OpticalSurface("LarSurface");
>     G4LogicalBorderSurface* LarSurface =  new G4LogicalBorderSurface (
> "LarSurface",PVLAr,PVsteel,OpLarSurface);
>     OpLarSurface->SetType(dielectric_metal);
>     OpLarSurface->SetFinish(polished);
>     OpLarSurface->SetModel(glisur);
>     LarSurface->DumpInfo();
>
>
>


-- 
David Sarrut, Phd
Directeur de recherche CNRS
CREATIS, UMR CNRS 5220, Inserm U1206
Centre de lutte contre le cancer Léon Bérard
28 rue Laënnec, 69373 Lyon cedex 08
Tel : 04 78 78 51 51 / 06 74 72 05 42
http://www.creatis.insa-lyon.fr/~dsarrut
_________________________________
 "2 + 2 = 5,  for extremely large values of 2"
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