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Re: None Optical photons stopping at boundary of scintillator (Mario)
Date: 18 Nov, 2010
From: Gumplinger Peter <Gumplinger Peter>

Dear Mario,

Your luck, I also monitor this Forum, but you are more guarantied to get a response to this kind of question on the 'Optical Physics Forum'.

I see that you define two types of surfaces:

      OpScintSurface->SetType(dielectric_dielectric);
      G4LogicalBorderSurface* ScintSurface
                     new G4LogicalBorderSurface("OpScintSurface",                                             
                         scintillator_phys,experimentalHall_phys,OpScintSurface);

      new G4LogicalSkinSurface("TiO2Surface",scintillator_log,OpScintSurface);

Now, I think, this is partly because you wanted to toggle between a dielectric_dielectric surface and a dielectric_metal one. So, the second, should read:

        new G4LogicalSkinSurface("TiO2Surface",scintillator_log,TiO2Surface);

BUT, one of the two definitions needs to be commented out. You cannot have two definitions for essentially the same real surface. You have to decide between one or the other. With both assigned, the logic in G4OpBoundaryProcess gives precedent to the G4LogicalBorderSurface. Now, a dielectric_dielectric, has to have a material on the outside that has an index of refraction - your "Air". You have failed to assign n=1 to the "Air". This is the reason that your photons just stop. Snell's Law cannot be evaluated.

If you'd used the G4LogicalSkinSurface, instead, with the above change, everything should also work, though you'd get only absorption/reflection (no refraction) even if the "Air" has no refractive index because, in that case, none is required for the tracking.

Hope this helps, Peter

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1 Question: Re: Optical photons stopping at boundary of scintillator   (Mario - 19 Nov, 2010)
(_ Feedback: Re: Optical photons stopping at boundary of scintillator   (Gumplinger Peter - 19 Nov, 2010)
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