Dera Shirley,
There is one possible answer, please check and let me know if the problem
persists:
In the source.f, momentum and kinetic energy are not consistent: In the
kinetic energy, the mass of your selected particle is used (ID) , but in
the momentum calculation, the mass is the one of "IONID" that is set by
default to the primary in the BEAM card (a muon in your case.)
The effect is unpredictable. (maybe we'll introduce a check..)
TKEFLK (NPFLKA) = ENEGY - AM(ID)
* Particle momentum
c PMOFLK (NPFLKA) = PBEAM
PMOFLK (NPFLKA) = SQRT ( TKEFLK (NPFLKA) * ( TKEFLK (NPFLKA)
& + TWOTWO * AM (IONID) ) )
Regards
Paola
> Dear FLUKA users,
>
> I am studying particle propagation in liquid argon. When I look at proton
> energy loss, DTRACK in mgdraw, I thought it should be ~= CTRACK * dE/dx
> rate. While this seems true (with fluctuations) for almost all proton
> tracks, occasionally I get very large DTRACK, compared to CTRACK * dE/dx.
> For example, for the input attached below, I get the following examples:
> ncase jtrack etrack ptrack z0 z1 ctrack
> dtrack
> 25.0 1.0 1.009945 0.373675 0.0 0.768607 0.785268 0.229055
> 37.0 1.0 0.961867 0.211738 0.0 0.037436 0.127902 0.118133
> 43.0 1.0 0.968080 0.238378 0.0 0.052170 0.193938 0.137920
>
> KE dEdx ctrack*dE/dx
> 0.071672 0.009352 0.007344
> 0.023595 0.022066 0.002822
> 0.029808 0.018381 0.003565
>
> Here the dEdx rate is interpolated from FLUKA output .out file for
> protons. These protons are not near boundary or anything. And the dtrack
> is not only longer than ctrack*dE/dx, but they are also larger than the
> proton kinetic energy. So I'm not sure if I misunderstand what DTRACK
> means. Does anyone understand this?
>
> My inputs attached below. The source file is user-defined because I'm
> injecting secondary particles coming out of another generator. I cannot
> reproduce this behavior when I just inject primary protons in FLUKA.
>
> Thank you very much!!
>
> Shirley
>
Paola Sala
INFN Milano
tel. Milano +39-0250317374
tel. CERN +41-227679148
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Received on Sat Jul 14 2018 - 20:14:04 CEST