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Question Reflectivity of dielectric_metal border 

Forum: Processes Involving Optical Photons
Date: 25 Mar, 2015
From: Thomas Bonnet <Thomas Bonnet>

Hello, I'm trying to setup a very simple simulation with a scintillator and a reflective surface.

My geometry is a G4Sphere filled with a scintillator material. I added optical properties to my material (RINDEX and ABSLENGTH) as well as scintillation properties (SCINTILLATIONYIELD, RESOLUTIONSCALE, FASTTIMECONSTANT, SLOWTIMECONSTANT, YIELDRATIO). At this stage, everything is fine. I fired a 1 MeV gamma in the volume and can see optical photon created with the right yield.

Next, I tried to build a reflective surface on the sphere. So I made an optical skin surface attached to the scintillator sphere with a reflectivity property and I built an outer detection sphere to count the number of optical photons going out of the scintillator. Surprise : when I set the reflectivity to 1. all the photons can go through the sphere => no reflection at all on the surface. Then I tried to set reflectivity to 0.5 : the number of detected photons is divided by 2. And with a reflectivity of 0. no photons go through the surface.

So my question is : is reflectivity really represents reflectivity or transmission coefficient?

Also, when I look at the /tracking/verbose 1 output for optical photons I only see transportation process, no reflections nor absorptions. Is it something normal?

I hope this is clear, my detector construction is attached to this post.

Cheers.

Thomas.

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      http://hypernews.slac.stanford.edu/HyperNews/geant4/get/AUX/2015/03/25/06.06-25368-GeometryConstruction.cc

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1 Feedback: Re: Reflectivity of dielectric_metal border   (Gumplinger Peter - 25 Mar, 2015)
(_ None: Re: Reflectivity of dielectric_metal border   (Thomas Bonnet - 26 Mar, 2015)
(_ Feedback: Re: Reflectivity of dielectric_metal border   (Gumplinger Peter - 26 Mar, 2015)
(_ None: Re: Reflectivity of dielectric_metal border   (Thomas Bonnet - 27 Mar, 2015)
(_ None: Re: Reflectivity of dielectric_metal border   (Gumplinger Peter - 27 Mar, 2015)
(_ None: Re: Reflectivity of dielectric_metal border   (Thomas Bonnet - 13 Apr, 2015)
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