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Question Crystal Wrapping Surface 

Forum: Processes Involving Optical Photons
Date: 13 Oct, 2014
From: <cddcdd>

Hi,

I would just like to confirm that I am setting up the surfaces properly. My setup is a scintillation crystal shaped as a G4Trap with a PMT detector facing one face fo the crystal. I have deliberately placed an air gap between the pmt and crystal. Originally did not add any optical surfaces to the simulation and it seemed to run fine using the refractive index info. I have now added a Tyvek wrapping to the crystal and this is where i am having trouble with the optical surfaces.

I added the wrapping by making a solid that is the same shape of the crystal except hollow and slightly bigger. This allows the solid to enclose all sides of the crystal except the pmt end. There is a very small air gap between the wrapping and the crystal.

Now for the surface I have:

    //Surface properties for the wrapping

    G4OpticalSurface* ScintWrap = new G4OpticalSurface("ScintWrap");

    new G4LogicalBorderSurface("wrap_surf",physiWorld,physi_wrapping,ScintWrap);

    ScintWrap->SetType(dielectric_dielectric);
    ScintWrap->SetFinish(ground);
    ScintWrap->SetModel(unified);

    G4MaterialPropertiesTable* scintWrapProperty = new G4MaterialPropertiesTable();

    scintWrapProperty->AddProperty("REFLECTIVITY",photonEnergies,Tyvek_reflectivity,NUMENTRIES);
    ScintWrap->SetMaterialPropertiesTable(scintWrapProperty);  

This is for the coupling of the air to the Tyvek. Do I also need to add a surface for the air back to the crystal? or will the refractive indices be enough to take car of that transition?

I also added a MPT to the Tyvek material which defined its reflectivity and refractive index is this still necessary with the surface?

Thanks

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1 None: Re: Crystal Wrapping Surface   (cddcdd - 14 Oct, 2014)
(_ Feedback: Re: Crystal Wrapping Surface   (Gumplinger Peter - 15 Oct, 2014)
(_ More: Re: Crystal Wrapping Surface   (Gumplinger Peter - 15 Oct, 2014)
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