Dear Brian,
> On 05 Jul 2016, at 23:54, Zhu, Xiaoyu Brian <bxyzhu_at_lanl.gov> wrote:
>
> Hi FLUKA experts,
>
> I have been using a simple simulation to study the flux of neutrons induced by muons in lead.
>
> 1) How do I convert the neutron fluence output of usrbdx/usrsuw to a neutron flux? What I have done is first normalize the integrated fluence (1/cm^2) by the initial number of primary particles generated, then scale by the incoming flux of the muons (1/cm^2/s), and finally multiply by the cross section of the muon beam to cancel out units to get the proper units (1/cm^2/s). Is this the proper conversion?
The number are already normalised n/cm^2 / GeV /sr /primary, so you have to scale it to the incoming muon flux muon/s (see note 2 of the USRBDX manual page)
for flux I would usrbdx with current
Another option is to use the USRYIELD.
For further clarification about fluence/flux estimation I would point you to
http://www.fluka.org/web_archive/earchive/new-fluka-discuss/8501.html <
http://www.fluka.org/web_archive/earchive/new-fluka-discuss/8501.html>
> 2) There is a disconnect in the fluence at 20 MeV corresponding to the divide between the low-energy and high-energy neutrons. From what I understand, this is a problem of the binning and not in the physics but I don’t quite understand what I need to do to resolve the issue in the plot.
You should try to plot the content of the bin normalised to the bin width i.e. (y*DeltaY) option in flair while plotting.
Best,
Vittorio
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Received on Thu Jul 07 2016 - 01:23:54 CEST