RE: [fluka-discuss]: Number of ionizations in a region

From: Francesco Cerutti <>
Date: Sun, 17 Nov 2013 12:15:03 +0100

Dear Angelo

I'm afraid there is some basic misunderstanding:

- FLUKA, as any condensed history code, is not at all designed to describe
single ionization events releasing electrons below the delta ray
threshold, which in FLUKA has a hard limit at 1 keV (still you need to
lower it down from the default value). This means that you can ask the
code to explicitly generate and transport electrons above 1keV (and
scoring the generalized particle NET-CHRG you can get the charge variation
in the space), but all other ionization losses are considered as
continuous along the primary particle track and not as discrete events
yielding electrons you can score. The associated piece of info you can get
is just the energy deposition along the track.

- tracklength [cm] density [cm-3] is the definition of fluence [cm-2]. As
you score it on a regular USRBIN mesh, then you do not need at all the bin
volume: this is known by the code and used to get tracklength density in a
bin out of the tracklength calculation. If instead you score by region,
then you will just get tracklength [cm] since the code does not know the
region volume, as indicated by Vittorio.



Francesco Cerutti
CH-1211 Geneva 23
tel. ++41 22 7678962
fax ++41 22 7668854

On Fri, 15 Nov 2013, Angelo Infantino wrote:

> Sorry,Little correction to my previous mail. Correct me if I am wrong.
> The USRBIN calcualtes the particle tracks density right? So it needs the
> volume to get particles/cm2/primary.
> So the question is what volume is used? (not what surface!) 
> What about the region binning?
> Thank you
> Angelo
> ____________________________________________________________________________
> From:
> To:
> CC:
> Subject: RE: [fluka-discuss]: Number of ionizations in a region
> Date: Fri, 15 Nov 2013 18:45:33 +0100
> Dear Nikhil,When I score particles with USRBIN I obtain a fluence/primary.
> For example, if I filter with AUXSCORE only the ELECTRONS, with a XYZ mesh,
> I obtain the #e/cm2/primary. Correct? 
> But what is the surface that the score use to normalize the result? The
> surface of the bin that I created? 
> And what about the region scoring? I get the #e/primary in the whole region?
> Last question: If I score charged particle, i.e. electrons, how I can say
> that these electrons not came also from interactions of photons
> (photoelectric effect, compton ecc) or other particles?
> Thank you.
> Angelo
> ____________________________________________________________________________
> Date: Fri, 15 Nov 2013 10:33:46 +0100
> Subject: Re: [fluka-discuss]: Number of ionizations in a region
> From:
> To:
> CC:
> Dear Angelo,
> you can try scoring the charged particles and then normalize to the proton
> current. For example, one can score different kinds of charged particles
> using USRBIN.
> Cheers,
> -Nikhil
> On Thu, Nov 14, 2013 at 7:38 PM, Angelo Infantino <>
> wrote:
> Dear Fluka experts,I'm trying to calculate the number of
> ionizations given by a proton beam in a region. At the end I
> want to get the current generated in uA (only by the primary
> protons).
> To figure out how to get this number I built a very simple geometry: A
> proton beam (13 MeV pencil beam with no spread in energy and
> direction) on a cylindrical target of copper, thick enough to stop
> completly the beam. The target is surrounded by a region of vacuum and
> blackhole. My goal is to score the current (in uA) generated by the
> primary particles in the copper target.
> Is it possible to do with the standard score of fluka?
> Thank you in advance!
> Angelo
Received on Sun Nov 17 2013 - 13:17:54 CET

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