[fluka-discuss]: Boundary crossing artefacts: Fano test

From: Ferreira De Almeida Lourenco, Ana <am.lourenco_at_ucl.ac.uk>
Date: Sun, 5 Jun 2016 12:28:49 +0000

Dear Fluka experts,

I've been performing a self-consistency test called the "Fano test" in Fluka. The test states that under charged equilibrium conditions (when dose is uniform), the charged particle fluence is independent of the mass density as long as the cross-sections are uniform.

After a few tests, the results show some artefacts at boundaries. I'm simulating an homogeneous plane-parallel proton beam of 250 MeV (discarding nuclear interactions) in water. After a build-up region of 40 cm (the range of the beam in water), there is charged-particle equilibrium (CPE) as you can see in the graph below, where dose was scored with depth in cm. The CPE region starts at -6cm where the dose is uniform.


However, when I divided my geometry in different regions of water (the material is the same, composition, I-value, density, ...), the results show some artefacts at the boundaries, as you can see in the graph below. Same simulation as above but divided in regions at -4cm and 0cm.


I've played with the size of the steps using the FLUKAFIX card and activated single scattering at boundaries using the MULSOPT card, however the artefact is still there.

How can I correct for this?

Many thanks,


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Received on Sun Jun 05 2016 - 17:01:47 CEST

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