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Question Optical photon transport problem in G4Sphere 

Forum: Geometry
Date: 20 May, 2008
From: Paola <paola.solevi@cern.ch>

Dear G4 experts,

I'm using G4 to simulate the optical photon transport in 
LYSO crystals.
My geometry is composed by:

1) Air World volume
2) LYSO crystal (different geometries)
3) Air layer 
4) Detection layer (i.e. efficiency of the LogicalSurface 
between AirLayer and DetectionLayer = 1)

The surface of the LYSO crystal is:
new G4LogicalBorderSurface("alcoated_surf",PhysLYSOVolume,
                           PhysWorldVolume, alcoated_opsurf);


I cannot use G4SkinSurface since the surface between the crystal and 
the AirLayer is not Aluminum coated and I want optical photons to be 
transported according to the Rindex of the two materials (LYSO-Air). 

When using a semi-spherical geometry for the LYSO crystal, it 
seems that the optical photons "see" the surface of the Sphere 
even when it should not be defined:

 G4double  pSPhi   =   0.*deg2rad; 
 G4double  pDPhi   = 360.*deg2rad; 
 G4double  pSTheta = 0.*deg2rad;   
 G4double  pDTheta =  90.*deg2rad; 

 LYSOVolume = new G4Sphere("Crystal",0.,lysoR,pSPhi,pDPhi,pSTheta,
                           pDTheta);

I checked everything by means of visualization, please see 
the picture at: http://moby.mib.infn.it/~solevi/SphereOptics.gif

To check the code I performed a second simulation with a cylinder 
(G4Tubs), instead of G4Sphere, coupled on the bottom circular 
surface to the Air Layer and it seems to work fine.

Is it possible that the surface (and hence the normal to the surface) 
is defined over 4*Pi, independently on the volume definition?

Can anybody provide me some hints?

Thanks for your reply,

best regards
	Paola



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1 None: Re:Optical photon transport problem in G4Sphere   (Tatiana Nikitina - 21 May, 2008)
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