RE: IRRPROFI with non-monoenergetic beam

From: Joachim Vollaire <>
Date: Sun, 28 Nov 2010 17:29:57 +0000

Dear Frances,

I think you should use the integrated (in energy) number of neutron per second.
If the source routine is correctly defined (either you sample each bin
with the same probability and you adjust the weight of the sampled particle accordingly or
you sample the energy with a probability corresponding to
each energy bin content and assign a weight equal to unity....) then the energy distribution
of your beam should be preserved. Both sampling methods
should be equivalent, using one or the other depend on your problem,
if particle energies with low probability of occurrence contribute significantly
to your scoring then the first one should be preferred....
If this is not the case it is more optimal to spend more
time on particles with "big weights" using the second method....


Date: Mon, 15 Nov 2010 12:57:27 +0000
Dear Fluka users,
    I am trying to model the irradiation of a sample with a neutron beam.
I have the beam spectrum (in terms of energy bands and neutron flux in
each energy band) and so can use the SOURCE user routine to sample the
primary particle energy according to the instructions in the Fluka
manual for biased sampling.
I then set up the IRRPROFI card to define the irradiation profile. This
requires beam intensity in particles per second. My question is, what
beam energy will Fluka use for this irradiation if I am using the
user-defined source ?
If I set the beam intensity (assuming sample is uniformly irradiated), will the primary particle weights
calculated in the SOURCE routine ensure that the correct proportion of
the total flux is assigned to each energy band in the spectrum ? If not,
can anyone suggest how I can do this ?
Any help would be much appreciated,
Received on Sun Nov 28 2010 - 23:01:12 CET

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