Hi
the reason you seed a fraction of optical photons "absorbed" despite
putting to 0 the absorption coefficient, is very simple.
You need to specify the range of wavelengths that you want transported,
the default (see the manual for OPT-PROP) is narrower than the range of
production you asked for -> some photons are produced and immediately
discarded.
To achieve this, just add the two following cards to your input (be
ceareful, the mailer will likely wrap them around):
OPT-PROP 1.9E-5 9.1E-5 OXYGEN
WV-LIMIT
OPT-PROP 1.9E-5 9.1E-5 AIR
WV-LIMIT
Also, you are right that the production cone is 60 degrees and that the
critical angle at the region-1/region-2 boundary is 30 degrees, but this
means that ALL photons will get reflected because of total reflection
because their incidence angle is larger than the critical one, not the
opposite.
Ciao
Alfredo
>
> Dear Fluka expert,
> Recently, I have tested many Cherenkov light models and found that there
> are always some problems that cannot be solved and have been bothered for
> nearly a month.
> During the test process, I found that:
> 1. Like the source I set in Inp, the generated Cherenkov light will be
> emitted on the cone at an angle of 60 ° with the beam direction. When I
> set the refractive index of the material in region 1 to 2 and the material
> in region 2 to 1, according to Snell’s theory, the critical angle of total
> reflection at the boundary between regions 1 and 2 is 30 °, which means
> that all the generated Cherenkov light can pass through the boundary from
> region 1 to region 2, But I found that at 60 ° (with respect to the space
> angle is Π） It is found that 40% of the photons enter the void region
> through the boundary from region 1, which is completely inconsistent with
> the total reflection theory.
> 2.No matter how I change the refractive index n of region 2, 40% of the
> photons are absorbed and 60% escape. I don’t understand the meaning of
> absorption,and these 40% of the photons are at 60 ° (space angle Π） Is
> recorded in usrbdx. When I change the material of region 2 to
> ‘blackhole’, 100% of the photons escapes, Does that mean that 40% of the
> photons in the previous case entered region 2 from region 1?
> No matter whether you can put forward a solution to the problem, i would
> like to express my most sincere thanks!
> Attachment is Inp file.
>
>
>
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Received on Thu Jun 23 2022 - 22:58:20 CEST