Fwd: muon-induced neutron yield calculation

From: Yung-Shun Yeh <adair.py94g_at_nctu.edu.tw>
Date: Tue, 6 Aug 2013 12:23:46 +0800

Dear FLUKA experts,

I am studying the cosmic-ray muon induced neutron in underground
laboratory, and would like to ask you how to retrieve neutron information
using mgdraw.f user-defined function.

To calculate the detection efficiencies of muon-induced neutron, I try to
generate a set of neutron samples according the mean muon energy in our
laboratory. I would like to reproduce the results in PhysRevD.64.013012.
The simulation setup is that mono-energy energetic muon beam injects into
the liquid scintillator. The liquid scintillator is C10H22 filled in a
cylinder with height 4500cm and radius 500cm. I use mgdraw.f to retrieve
the properties of neutron produced during the muon propagating. For
neutron-indcued neutron case, highest energy neutron is treated as parent
particle, and avoided double count.

I plot the neutron energy spectra. For high energy neutron(>20MeV), the
neutron spectrum looks well comparing with the paper, but for low energy
part below 10MeV, there are two spikes around 9MeV and 0.4MeV, which I
think abnormal ones. The PRD paper did not show the low energy behavior, so
I am unable to do a comparison. Please see the figure. The x axis is in GeV.

I read the manual, and learnt for low energy neutron with energy<20MeV,
FLUKA deals with neutrons as group algorithm, but mgdraw.f deals with
neutrons particle by particle. I also noticed in the previous discussion,
it is not suggested to use mgdraw.f to get information of low energy

My question is: how do I modify mgdraw.f to get correct information of low
energy neutron? Or is there a alternative way?

Yung-Shun Yeh
Received on Tue Aug 06 2013 - 13:02:58 CEST

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