Re: [fluka-discuss]: Roughness of material

From: paola sala <>
Date: Thu, 8 Jun 2017 12:04:49 +0200

Dear Viktor
the quantity to be changed is the retrun value of the function (it set
to 0 in the template).
The code "smears" the direction of the normal to the surface,
sampling the cosine of its angle with respect to the "unperturbed" normal ,
assuming a gaussian distribution of this cosine, centered at 1
(unperturbed value), with variance=FRGHNS.
Reflection and refraction are calculated with respect to the "new"
normal to the surface.
The value of FRGHNS is bounded to be smaller than 0.5.

Hope this helps, and..
The documentation will be updated!


On 06/07/2017 10:56 AM, Віктор Родін wrote:
> Hello dear FLUKA users,
> I'm working with optical photons now and want to compare differencies
> beetwen roughned and smooth surfaces. FLUKA sets ideal smooth surface
> of material by default. I have found description of *frghns*
> subroutine in Online FLUKA manual but I still wandering what to change
> in it:
> Argument list (all variables are input only):
> TXX, TYY, TZZ : particle direction cosines
> UXSRFC, UYSRFC, UZSRFC: direction of the normal to the surface
> MREG : region the particle is coming from
> NEWREG : region the particle is going to
> MMAT : material the particle is coming from
> MMATNW : material the particle is going to
> Function FRGHNS can be used to return a non-zero value for the
> roughness of a boundary between two materials, relevant for
> optical photon transport (default roughness is zero for all
> boundaries).
> Perhaps, it must be U_SRFC because it defines new direction. What are
> the values of roughness at the output?Could someone (more experienced)
> explain me more clearly about this?I'll be grateful for help.
> Best regards,
> Viktor Rodin

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Received on Thu Jun 08 2017 - 13:05:11 CEST

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