Hi
it looks like there is some single precision variable, either in the
writing or reading procedure, that cuts your rounding.
Please check all the steps, and be sure to use double precision variables
(the default in FLUKA) and to write them with enough decimals.
You might also want to try the predefined FLUKA scoring options.
Ciao
Paola
> Dear experts,
> I have a question on the numerical precision which FLUKA can get on the
> angular distributions.
> I simulated a 400 GeV proton beam incident on a thick Be target, 50 cm
> long.
> I modified the mgdraw.f routine in order to get an ASCII file with the
> information I need.
> I am interested in the particles produced and going out of the target at
> very small angle, say less than 0.2 mrad. I simulated my geometry with
> cylindrical symmetry along z axis, so I am interested in particles with
> ZSCO close to 1.
> I see that the next value less than 1 is ZSCO=0.99999994, corresponding to
> an angle of 0.00034641 rad. So I cannot get a continuous distribution in
> that angle range.
> I am attaching two plots to show you the issue, they show the polar angle
> vs kinetic energy for neutrons, one is with angle less than 10 mrad, and I
> suppose that the distribution is reasonable, and the other is for angle<1
> mrad.
> I am wondering if there is any way to increase the precision.
> Also, can you please tell me if the distribution I get is the expected one
> or if you see further issues with that?
> Thank you,
> best regards,
> Roberta Volpe
>
Paola Sala
INFN Milano
tel. Milano +39-0250317374
tel. CERN +41-227679148
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Received on Tue Oct 13 2015 - 09:22:37 CEST