Re: [fluka-discuss]: RE: Muon production questions

From: Anna Ferrari <>
Date: Sat, 10 Jun 2017 10:39:21 +0200

Dear Alexander,
the differential distribution you will obtain will be in kinetic energy. If
you look at the USRTRACK card description (page 259 of the pdf manual, for
example) you can find this in the what's explanation.
By the way: results are given -as you wrote- in part cm^-2 GeV^-1 per
primary, provided that you input the volume of the region where you do the
USRTRACK scoring (what(5) in the first card). If you don't do this the
volume is set to 1 cm^3 and you get in practice the integral of the
tracklength over the region. I say this because I gave a look at your input
and this value is missing... in addition, you have selected to score in all
regions, then I guess that the results you get (the absolute numbers, the
shape of the distribution is obviously correct) are quite far from
reasonable values. If you want results per cm^2, just take care (see Note 8
of USRTRACK card description in the manual).

Hope it helps and kind regards,

Am Fri, 9 Jun 2017 14:54:58 +0000 schrieb <>:
> Dear Roberto,
> That solved my problem, thank you very much for your help! The slides were very useful, and my results look more sensible now.
> I do have a further question, regarding the USRTRACK output units (part/cm^2.GeV.primary). Are the energy units in the denominator in terms of kinetic energy or total energy? I tried looking in the FLUKA lectures on this, but wasn't able to figure this out for sure.
> Thanks again,
> Alex
>From: Versaci Roberto []
> Sent: 08 June 2017 10:37
> To: Brynes, Alexander (STFC,DL,AST);
> Subject: RE: Muon production questions
> Dear Alexander,
> I believe that the problem arises from the fact you turned on the photoproduction of mu pairs only, rather then all types of photonuclear interaction.
> I would suggest you to have a look at lecture on electromagnetic interaction from the last fluka course
> and to add a PHOTONUC card with an empty SDUM.
> Cheers,
> Roberto
> ________________________________
>From:<> [] on behalf of<> []
> Sent: 08 June 2017 10:20
> To:<>
> Subject: [fluka-discuss]: Muon production questions
> Dear FLUKA experts,
> I am trying to simulate muon production via an electron beam interacting with a target (see attached file) - we have some simulations from GEANT4 and I am attempting to reproduce the results.
> There are some discrepancies between the simulations - for example, I can only produce muons if I introduce a biasing factor in WHAT(3) of the PHOTONUC card (maybe I am missing something?).
> Also, I may be having issues understanding the units of the USRTRACK output. As I understand it, the units from this card are in part/(cm^2.GeV.primary) - is the energy in units of kinetic energy or total energy?
> Any advice you could offer would be very helpful.
> Thanks,
> Alex

Dr. Anna Ferrari
Institute of Radiation Physics
Helmholtz-Zentrum Dresden-Rossendorf e.V.
Tel. +49 351 260 2872

Vorstand: Prof. Dr. Dr. h. c. Roland Sauerbrey, Prof. Dr. Dr. h. c. Peter
Vereinsregister: VR 1693 beim Amtsgericht Dresden

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Received on Sat Jun 10 2017 - 11:52:25 CEST

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