Dear Ana,
all point point then to those general indications (
http://www.fluka.org/content/course/NEA/lectures/StatSampl.pdf) which I was
always given
- Never forget that the variance itself is a stochastic variable subject
to fluctuations
- Be careful about the way convergence is achieved: often (particularly
with biasing) apparently good statistics with few isolated spikes could
point to a lack of sampling of the most relevant phase-space part
- Plot 2D and 3D distributions! In those cases the eye is the best tool
in judging the quality of the result
I guess you have then a lot of bins and you lack statistics, although the
merging tools should handle it. In your particular case those are escaping
protons on the side of the target.
I'll need to check it better, but I would increase the statistic and reduce
the number of bins you have first.
Vittorio
On Mon, Jul 6, 2015 at 11:51 AM, Ferreira De Almeida Lourenco, Ana <
am.lourenco_at_ucl.ac.uk> wrote:
>
> Dear FLUKA experts,
>
> I am simulating a proton beam in a target cylinder and scoring fluence
> differential in energy and angle in a ring detector using a USRBDX card.
>
> For a non zero fluence I'm getting a error of zero. Why is the error
> zero? Example of sum.lis file:
> ...
> Tot. resp. (Part/cmq/pr) 0.8798609 +/- 0.000000 %
> ( --> (Part/pr) 0.8798609 +/- 0.000000 % )
> ...
>
> Also, in the sum.lis files the angular distribution and respective
> fluence are given in units of steradians and degrees. How are these two
> quantities related?
>
> Please find attached my input file.
>
> Many thanks,
>
> Ana
>
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Received on Tue Jul 07 2015 - 13:33:48 CEST