The USRBIN scorer allows to score fluence in a spatial mesh structure
(usually X-Y-Z or R-Phi-Z) independent of the geometry. To score neutron
fluence, put WHAT(2) = NEUTRON. This will give you as output the
average fluence in each mesh cell in neutrons/cm2/unit primary weight
(where the "primary weight" is usually just "1." for each primary beam
particle unless you use variance reduction techniques which modify the
primary weight), which can be nicely visualized using FLAIR.
Knowing the primary particle beam current in protons/s (in your case,
the primary particles are protons), you can simply normalize the USRBIN output
by this value (e.g. in the "Norm:" field in the FLAIR "Plot" section for
USRBIN plotting) to get neutrons/cm2/s.
The USRBDX scorer allows to score the fluence in an energy binning for
particles crossing a boundary in the geometry. This will give the double
differential distribution of fluence in energy and solid angle. To obtain
integral binned results in particles/cm2/(primary weight) you have to
multiply with the solid angle interval that you specified in the
USRBDX card (this can be done using the "Y Norm:" field in the FLAIR
section for plotting) and the width of the energy bin (conveniently done
in FLAIR setting the "Value:" field to "DX*Y). To go to particles/cm2/s,
multiply the solid angle interval with the primary particle beam current
(again in the "Y Norm:" field).
The USRTRACK scorer also allows to score fluence, this time using the
summed length of tracks inside a region volume of the geometry. It will
give the results as single differential distribution in energy, to get to
particles/cm2/(primary weight) you have to multiply with the width of the
energy bin ("DX*Y", see above), and again multiply by the primary particle
beam current if you want to have the results in particles/cm2/s.
Both for USRBDX and USRTRACK scoring, you have to give the correct area or
region volume to get the correct normalization.
About the different ways which are used to obtain the fluence in the
different scorers I refer you to the "scoring" lecture in one of the recent
FLUKA courses at
http://www.fluka.org/fluka.php?id=courses&sub=ALL.
Cheers,
Stefan
--
Stefan E. Mueller
Department of Information Services and Computing - Computational Science
and Institute of Radiation Physics
Helmholtz-Zentrum Dresden-Rossendorf
Tel: +49 (0351) 260 3847
Stefan.Mueller_at_hzdr.de
http://www.hzdr.de
Vorstand: Prof. Dr. Sebastian M. Schmidt, Dr. Diana Stiller
Vereinsregister: VR 1693 beim Amtsgericht Dresden
On Mon, 24 May 2021, Muneeb Wajid wrote:
> The two scoring cards which can be used for scoring the radiation flux over
> time are the USRBIN and USRBDX cards.The USRBIN card can score the fluence
> and dose in a grid of bins and can be used to score fluences, dose and
> energy deposition of a wide range of particles. If the contribution of a
> single particle to the dose equivalent is requested, one has to add an
> AUXSCORE card. The AUXSCORE provides the conversion
> factors corresponding to the particle requested.
>
> The USRBDX is used to score a fluence spectrum of particles which cross a
> certain boundary.
>
>
> On Mon, May 24, 2021, 1:53 PM 성균관대학교MUSTAFA <mumyapan_at_g.skku.edu>
> wrote:
> Dear FLUKA experts,
>
> In my simulation ( 1GeV proton beam hit the target and producing
> neutron), how can I calculate the neutron flux ( which scoring card
> can I use ) and how can I convert the unity as a neutrons per
> centimeter squared per second?
>
> Thank you in advance.
>
> Best regards
> Mustafa
>
>
>
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Received on Tue May 25 2021 - 11:40:31 CEST