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Question Optical Photons not getting reflected from Auminium. 

Forum: Processes Involving Optical Photons
Date: 21 Apr, 2012
From: Ashwath Rao <Ashwath Rao>

Respected Experts,

I observe that the optical photons are not crossing the crystal boundary. I had thought that this could be because of the OpBoundaryProcess(), but then commenting it made the photons to scatter throughout my world volume area.

 pmanager->AddDiscreteProcess (new G4OpBoundaryProcess());
 pmanager->AddDiscreteProcess(new G4OpAbsorption());

Now there are two issues, I wish to get cleared with : 1) How to control the optical photons spread (a) for within the crystal and (b) scatter outside the crystal ?

2) There is an Aluminium layer over the NaI(Tl) crystal. (a) When the optical photons cross the crystal's boundary, how to make them, get reflected back into the crystal from the inner surface of the Al housing ? (b) does photon reflection cause any (optical photon)energy deposit dE(MeV) into the Aluminium ?

// in Detector Construction

  G4double pp[numentries] = {0.5*eV, 600.5*keV};
  G4double AlmRindices[numentries] = { 1.49, 1.49};
  G4double AlAbsorptionLength[numentries] = { 7.0*m,7.0*m };
  G4double specularlobe[numentries] = {0.0, 0.0};
  G4double specularspike[numentries] = {0.3, 0.3};
  G4double backscatter[numentries] = {.2, .2};
  G4double reflectivity[numentries] = {1., 1.};
  G4double efficiency[numentries] = {0, 0.};

  Alnm->AddProperty("RINDEX", pp, AlmRindices, numentries);
  Alnm->AddProperty("ABSLENGTH", pp,AlAbsorptionLength,numentries);
  Alnm->AddProperty("SPECULARLOBECONSTANT",pp,specularlobe,numentries);  
  Alnm->AddProperty("SPECULARSPIKECONSTANT",pp,specularspike,numentries);
  Alnm->AddProperty("BACKSCATTER",pp,backscatter,numentries);
  Alnm->AddProperty("REFLECTIVITY",pp,reflectivity,numentries); 
  Alnm->AddProperty("EFFICIENCY",pp,efficiency,numentries);

   G4OpticalSurface* NaI_Tl = 
   new G4OpticalSurface("CrystalSurface",glisur,polished,dielectric_metal);

   G4LogicalBorderSurface* CrystalSurface =
   new G4LogicalBorderSurface("CrystalSurface", pTube, pHouse, NaI_Tl);
   //pTube is for crystal and pHouse is for crystal housing.

  G4OpticalSurface* Al = 
  new G4OpticalSurface("HousingSurface",glisur,polished,dielectric_metal);

  G4LogicalBorderSurface* HousingSurface = 
  new G4LogicalBorderSurface("HousingSurface",  pTube, pHouse, Al);

Thanking everyone in advance, Regards, Ashwath.

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1 More: Re: Optical Photons not getting reflected from Aluminium.   (Ashwath Rao - 21 Apr, 2012)
2 Feedback: Re: Optical Photons not getting reflected from Auminium.   (Athreya Shankar - 24 Apr, 2012)
3 Feedback: Re: Optical Photons not getting reflected from Auminium.   (Ashwath Rao - 25 Apr, 2012)
1 Feedback: Re: Optical Photons not getting reflected from Auminium.   (Athreya Shankar - 27 Apr, 2012)
(_ Feedback: Re: Optical Photons not getting reflected from Auminium.   (Ashwath Rao - 29 Apr, 2012)
(_ Feedback: Re: Optical Photons not getting reflected from Auminium.   (Athreya Shankar - 04 May, 2012)
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