Definition of a rectangular beam

Dear Fluka users,

I need to compare calculation results from MCNPX and FLUKA with
experiment results from a square iron ions (1GeV/A) beam with a uniform
center of approximately 20 x 20 cm2. The beam fluence is about 8300
ions/cm2 and it is important to have the whole beam because µdishes were
used (with a biological target) and have a smaller size (diameter of
35mm) than the beam size.
MCNPX results and experimental dose are in good accordance (~0.2 cGy),
but not with FLUKA. I believe that my beam profile is wrong.

Should I modify in the subroutine SOURCE some variables to have an
isotropic distribution of ions between -10 cm and 10 cm (both for x and
y axes)?

Thank you in advance for your help.
Jean-Emmanuel

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Jean-Emmanuel Groetz
Laboratory of Physical Chemistry and Radiation
University of Franche-Comte
16, route de Gray
25030 Besancon Cedex
France
mailto: jegroetz_at_univ-fcomte.fr
phone: +33 3 81 66 65 07
fax  : +33 3 81 66 65 22
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