RE: [fluka-discuss]: Stopping power of protons in water (next part)

From: Alfredo Ferrari <alfredo.ferrari_at_cern.ch>
Date: Fri, 30 Jan 2015 07:30:43 +0100

... what Vasilis suggest is fine, however at larger energies you have also
to switch off completely delta rays (if not part of the dE/dx in form of
secondary electrons will escape the thin layer). An even better way
is (on top of what Vasilis suggests and of switching off completely delta
rays) to switch off Landau fluctuations (with IONFLUCT)
and multiple scattering (with MULSOPT) -> every proton will experience
only the average stopping power and nothing else -> 1 proton is enough to
get the value of dE/dx

                      Alfredo


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On Thu, 29 Jan 2015, Vasilis Vlachoudis wrote:

> Hi Jean Emmanuel,
>
> the best is the output from DELTARAY. You can always increase the tabulation by altering the WHAT(2) and/or WHAT(3)
>
> If you want to calculate with simulation (which is no-brainer in this case) but just for the fun of it
> - create a very thin geometry (e.g. thickness 10um) of WATER (use the default water material from FLUKA)
> - turn off the EMF (with EMF-OFF)
> - increase the dp/dx tabulation with the DELTARAY
> - set your proton beam at 30MeV
> - increase the inelastic/elastic interaction thresholds to something higher than your beam with THRESHOLD
> - score with USRBIN by region the total energy deposited
> divide your region-energy by your target thickness
> I've got 18.76 MeV/cm with 1e7 protons
>
> Vasilis
>
> ________________________________________
> From: owner-fluka-discuss_at_mi.infn.it [owner-fluka-discuss_at_mi.infn.it] on behalf of Jean-Emmanuel Groetz [jegroetz_at_univ-fcomte.fr]
> Sent: 29 January 2015 14:48
> To: FLUKA discussion ý[fluka-discuss_at_fluka.org]ý
> Subject: [fluka-discuss]: Stopping power of protons in water (next part)
>
> Dear all,
>
> Further to my message yesterday, I can clarify my needs.
> For example, the PTRAC database from NIST gives 18,75 MeV/cm for 30 MeV
> protons in water. How can I find this value after a fluka run with 1e6
> protons?
> A USRBIN card with only one bin in x and y gives me the dE/dx
> distribution along the z axis, but not the corresponding value from
> PSTAR or from the DELTARAY card.
>
> Thanks for your help.
> Jean-Emmanuel
> --
> _______________________________________________
> Jean-Emmanuel Groetz
> Laboratoire Chrono-Environnement UMR CNRS 6249
> Chimie-Physique & Rayonnements
> Université de Franche-Comté
> 16 route de Gray
> 25030 Besançon Cedex
> France
>
> mailto : jegroetz_at_univ-fcomte.fr
> tel : +33 (0) 3 81 66 65 07
> fax : +33 (0) 3 81 66 65 22
> http://chrono-environnement.univ-fcomte.fr/
> _______________________________________________
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Received on Fri Jan 30 2015 - 09:08:05 CET

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