Re: low energy neutrons, binning and complementary software

From: Vasilis Vlachoudis (
Date: Wed Oct 31 2007 - 17:15:49 CET

  • Next message: Stefan Roesler: "Re: USRBIN, binary output files, summation"

    Hi Vitaly,

    When you are using a fluence/current estimator in FLUKA for neutrons,
    you will get the results in a histogram where the bins will be defined
    in the following way:
    (Elow, Ehigh = low and high energy limits you are requesting in the
    input file)
    1) if Elow > 19.6 MeV: the binning intervals will be those you defined
    in the input file log or linear is your choice.
    2) if Ehigh < 19.6 MeV: The binning intervals WILL ALWAYS be the ones of
    the predefined groups in FLUKA, regardless the limits and number of bins
    you have requested. Look in the manual section 10. The first & last bins
    will be the ones containing the Ehigh, Elow value
    3) if Elow < 19.6 MeV < Ehigh: You will get the histogram split into
    two parts. First for the high energies like the (1) case, with the
    exception of the last bin that the lower limit will be always 19.6 MeV
    (FLUKA histograms go down in energy) . The number of bins in the first
    part will be less that what you have requested in order to keep the
    bin-size as is defined in the input. Second for the low energies will be
    given like in (2).

    If you ask fluence, FLUKAwill always give you the DN/DE. To plot it
    iso-lethargic you will have to multiply this value by the center of the
    bin <E>*Dn/DE. If your are plotting it in log-E, then <E> should be
    replaced by the geometric mean.

    The EA-MC program is a neutron simulation code written by C.Rubbia and
    cannot be distributed.

    Best Regards

    Vitaly Pronskikh wrote:
    > Dear FLUKA Experts,
    > could you please advice on the questions that arose while
    > looking at the presentation "Low-energy neutrons..." of
    > 1 Apr 2007, related also to n_TOF project.
    > Firstly, as I see, the neutron spectra binning is linear
    > in logarithmic scale, which allows the direct comparison to
    > other codes like MCNPX. But in my runs the binning always
    > varies, changing at the margin 0.0196 Gev. How can I make
    > is that smooth, like in you presentation?
    > The other question is concerning the code (subroutine?)
    > EA-MC, which was coupled with FLUKA in your presentation
    > in order to give structure of the thermal peak. Is it
    > available from anywhere, or at least what it works like?
    > This all is interesting in the context of the transmutation
    > calculations,

  • Next message: Stefan Roesler: "Re: USRBIN, binary output files, summation"

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