FLUKA: About GEOTRK

[Laurent Aphecetche <aphecetc@in2p3.fr>]

Hi,

Following the nice documentation about "22} How to write, compile and
link a user routine" A. Fasso sent on this list (I guess it was in
January), I would like to use the GEOTRK entry (in geoden.f) to get, for
instance, neutron fluences in a R-Z binning. I know USRBIN is able to do
it, but the idea behind this choice is to be able to :

1) have my own output of fluxes (directly within ROOT files) instead of
usual fluka outputs.
2) compute a mean and a sigma for each value scored (to get an idea of
statistical errors)

(BTW I did the same thing for the per-region scoring in GEODEN, and it
worked fine).

Now my problem : I thought I just have to sum over the RULL variable
(=track-length*weight = cm, right ?) in any R-Z cell I'd want to have,
in case IJ=8=neutron, and then to divide by my cell volume (=cm^-3), to
get my fluxes. But by doing that and looking at the output of a regular
USRBIN, e.g. :

*        |_________|_________|_________|_________|_________|_________|
USRBIN          11.0       8.0      71.0    111.47       0.0     187.0
MODE
USRBIN         11.47       0.0     -63.0       1.0                 2.0 &

I got different results. So my question is : what am I doing wrong here
? Is the USRSTB routine doing more complicated things than just a sum of
RULL ?

thanks for your help, and best regards,

-- 
Dr. Laurent APHECETCHE (mailto:aphecetc@in2p3.fr) (IN2P3-CNRS) 
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Collaborations PHENIX http://www.phenix.bnl.gov/~aphecetc et MEGAPIE.