Problem with the primary energy generation

Dear all,

I am facing some problems with the energy generation in the beam card.
I want to generate 1 GeV protons without any spread in energy or divergence to
study the response of a radiation detector device with a CsI(Tl) calorimeter.
When I read the collision file I prepared in MGDRAW I can notice some
important fluctuations in the primary energy histogram to lower energies when
generating an important number of events. The energy deposition in the
different elements of the detector is consistent with the "modified" primary
energy, therefore the scoring of the incident energy seems to be correct.

I have tried to generate the energies via the SOURCE routine and I find the
same problems. Moreover, when I try to generate a flat distribution in
energies (either BEAM card or SOURCE), the distribution I obtain shows a
substantial increase in the direction of the low energy range.

Any sugestion?

Best regards,

-- 
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Dr. Cesar Martin
Institut fuer Experimentelle und Angewandte Physik,
University of Kiel,
Leibnizstrasse 11,
D-24118 Kiel
Germany
phone (+)49 431 880 2491; Fax (+)49 431 880 3968
e-mail: martin_at_physik.uni-kiel.de
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