Re: About pion and muon productions

From: Anna Ferrari <>
Date: Mon, 11 May 2009 08:08:33 +0200 (CEST)

 Dear Hantao,

 your results cannot be in agreement with experimental data or
 previous calculations, because you did not calculate the pion
 (and the muon) yield in the correct way. From the input file you sent,
 it appears that you have calculated CURRENT and not FLUENCE!
 (you have set what(1)=-1. in all your USRBDX cards).

 As pointed out many times (see for example p.24-25 in: )

 the correct quantity to be used is FLUENCE. If you want quantify
 your particle field you need a surface independent quantity: fluence
 and not current. The pion field at your boundary crossing depends
 on the interactions in your volume; fluence, that is in a way
 a measure of the pion density there, is the correct quantity.

 I imagine that, due to the 1/cos(theta) weight and considering
 the correlation between energy and the angle of emission,
 your distributions will change...


 Anna Ferrari
 CNAO Foundation
 National Center for Oncological Hadrontherapy
 Strada Campeggi I-27100 Pavia (Italy)


> Dear Fluka experts,
> I want to simulate the muon production by the reaction of
> proton-Carbon at 1.6GeV. At the same time, I also want to know about
> pion+- productions in this reaction. For different-thickness Carbon
> targets, I calculated the pion+- production as showed in figure(in
> attachments).
> From the figure, we find that there is a very mild depth at pion energy
> of about 100MeV for pion production spectra. For thin target, the
> contribution from first peak dominates. With increasing the thickness of
> Carbon target, namely, 5cm, 10cm and 20cm, the second peak value become
> more important and even dominate at last. But I find there isn't this
> depth structure for the other calculated results from 'Treating High
> Energy Showers'(Alfredo Ferrari and Paola R. Sala) and experimental
> data(PHYSICAL REVIEW C 75, 024611 (2007)). Why does the depth structure
> appear? Is some wrong with my calculation by FLUKA?
> Secondly, the pion productions mainly are through the following the
> three mechanisms, namely,
> 1. single pion production
> $NN \rightarrow \pi NN$;
> 2. two-body process
> $NN \rightarrow \pi d$;
> 3. pion-pair production
> $NN \rightarrow NN \pi \pi$.
> In fluka, the above three mechanisms are all included ?
> For my input file(see attachments), are there any suggestions to me in
> order to obtain the better simulation results for pion and muon
> production?
Received on Mon May 11 2009 - 09:38:24 CEST

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