Hello,
protons undergo nuclear interactions in iron.
The interaction length is of the order of 10cm, therefore after 2m the
proton fluence should be reduced by a factor ~exp(-200/10)=exp(-20)=2x10-9
Hope this helps
Paola
> Hello,
>
> I'm very new to FLUKA and trying to learn by using very simple set-ups.
> One of these consists of an iron cylinder surrounded by vacuum and a 4GeV
> pencil proton beam irradiating it from one side (protons initially
> propagate along the cylinder's axis). I used USRBIN to also take a look at
> the fluence of the original protons inside the target and have the feeling
> that something is not OK. According to NIST/PSTAR
> (https://physics.nist.gov/PhysRefData/Star/Text/PSTAR.html) the projected
> range of 4GeV protons in iron should be about 3m (2.495E+03g/cm² /
> 7.874g/cm³) but the fluence in the simulation shows practically no (beam)
> protons beyond approx. 2m (see attached image). I cannot find the reason
> for this(*). Any hints?
>
> Thank you very much in advance for your support!
>
> Best regards,
> Serban Udrea
>
> (*) Initially I thought that I wrote the wrong number in the input file,
> but this was not the case (the *.out file contains a line confirming the
> 4GeV kinetic energy).
> --
>
> Dr. Serban Udrea
> Researcher
> p-Linac/p-Bar-Target
>
> Phone: +49 6159 71 3356
> Fax: +49 6159 71 3099
> S.Udrea_at_gsi.de
>
> GSI Helmholtzzentrum für Schwerionenforschung GmbH
> Planckstraße 1, 64291 Darmstadt, Germany, www.gsi.de
>
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Paola Sala
INFN Milano
tel. Milano +39-0250317374
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Received on Tue Oct 09 2018 - 16:23:23 CEST