Re: [fluka-discuss]: Dose rate at a point from Multiple sources

From: Answers <>
Date: Fri, 10 Apr 2020 17:42:21 +0200 (CEST)

In order to score DOSE-EQ you do not need to define specific regions, and
it is much better to leave air all around your shield.
The calculation of DOSE-EQ starts from particle fluences, not from
deposited energy. Particle fluences are convoluted with conversion factors
that depend on particle type and energy. The standard conversion
coefficients in fluka transform particle fluences in ambient dose
equivalent (H*(10)).
If you have cylindrical symmetry, You can define a cylindrical USERBIN
around your shield, with one or more inradial intervals and how many
longitudinal intervals as you need, then pick up the dose values in the
bin you need. If you do not have cylindrical symmetry, you can use
r-phi-z binning, or a cartesian binning.

If you ask for DOSE-EQ, do not put water around, it will absorb the
radiation and change the dose value.

And, do NOT use the AUXSCORE to select photons only: in reality, the
photons will produce electrons, that are the particles really depositing
energy. If you need dose you have to consider electrons. So, no AUXSCORE

If, instead, you really need dose in water, where dose is defined
deposited energy/ unit mass
then ask for DOSE in your region-by-region userbin.
AND do NOT use the AUXSCORE card, otherwise you will miss almost all
the deposited energy, because it is deposited by secondary electrons.
Photons do not deposit energy directly, it only happens in the simulation
because there are transport thresholds: photons below threshold
stop and their energy is counted as deposited there.

Hope this helps

On Thu, 9 Apr 2020, Raksha Rajput wrote:

> Dear Experts,
> I have a cylindrical source cage, with Co-60 cylindrical source at 25
> positions, equidistant. I wish to calculate dose at different points on the
> surface of the lead shielding. How should I calculate the dose rate at a
> point ? Presently I am scoring USRBIN/DOSE-EQ with AUXSCORE/PHOTON in SPH
> bodies of 5 cm radius, touching the surface of my shielding flask.
> Referring to the link below, I got answers to my questions but only for
> point no.5, please throw some more light, or suggest the specific options in
> the USRBIN card. 
> 80.html
> Thanks and regards,
> Raksha.

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Received on Fri Apr 10 2020 - 19:18:50 CEST

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