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Forum: Processes Involving Optical Photons
Re: Question Optical Surfaces and Sigma_Alpha (Wolfgang Lukas)
Date: 23 Jun, 2009
From: Gumplinger Peter <Gumplinger Peter>

The way I understand your problem domain, your aim is to find relative detection efficiencies. The absolute detection efficiency not only depends on energy deposition and hence the underlying EM processes, but also on more empirical and less known parameters such as reflectivities, bulk absorption etc. Therefore, I don't think you need to worry too much about the EM processes. That said, the StandardEM should just work fine for you, though you may want to compare with LowEnergy, Penelope, Livermore and/or consult experts monitoring the EM Forum.

> Teflon wrap = polishedbackpainted

> Diffuse paint = groundfrontpainted

Yes.

> Alu wrap = polishedbackpainted (with prob_ss = 1.0 for spike

> reflections at the aluminum surface - this should hopefully work just

> like a polished dielectric-metal surface with an air gap?)

Careful, the prob_ss etc. parameters correspond to the interface between the scincillator and the (implied) gap of the 'backpainted' option, not to the reflector behind the gap. This reflector is in the present implementation always assumed to be a Lambertian reflector. If this is not what you want, then I am afraid, you'll need to explicitly implement the gap in geometry and the dielectric_metal surface with the reflector as "polished" (in addition to the dielectric_dielectic interace between scint and gap also "polished").

> Can you recommend any "typical values" of sigma_alpha for diffuse paint

> and Teflon?

Use 100% 'specular lobe' and sigma_alpha of the order of 10deg for diffuse and order 1-2deg for Teflon (but those are not very educated suggestions!).

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1 Question: Re: Optical Surfaces and Sigma_Alpha   (Wolfgang Lukas - 01 Jul, 2009)
1 Feedback: Re: Optical Surfaces and Sigma_Alpha   (Benton Pahlka - 01 Jul, 2009)
1 Feedback: Re: Optical Surfaces and Sigma_Alpha   (Gumplinger Peter - 02 Jul, 2009)
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2 Feedback: Re: Optical Surfaces and Sigma_Alpha   (Gumplinger Peter - 02 Jul, 2009)
1 Idea: Re: Optical Surfaces and Sigma_Alpha   (Wolfgang Lukas - 22 Sep, 2009)
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