Re: Photon Beam Energy

From: Giuseppe Battistoni <>
Date: Fri, 9 Apr 2010 10:15:50 +0200 (CEST)

Dear Jeremy
from your input file it appears that you are not giving any
DEFAULTS command.
In this case FLUKA adopts the default of default settings (the one
called NEW-DEFA, see the manual). With this setting, energy cuts
prevent to trasport particles below 1 MeV and you cannot define a
photon beam of 150 MeV. In this case FLUKA reacts in this way (I didn't
know that)

However the solution is simple: soon after the TITLE card put the command
DEFAUTS with PRECISIO in the SDUM and your beam energy will be
understood correctly.
That is not enough: you MUST specify proper production and transport
energy cuts for electrons and photons with the card EMFCUT (see the manual!)
(Remember that the PRECISIO settings use a 100 KeV cut-off, but this is
relative to particles different from photons and e+e- )

        Best regards
                Giuseppe Battistoni

On Fri, 9 Apr 2010, Jeremy Northum wrote:

> Hello All,
> I am having trouble getting FLUKA to give me the correct beam energy. I am
> trying to simulate a 150 keV x ray beam using
> BEAM -0.000150 0.0 0.0 0.0 0.0 1.0PHOTON
> When I look through the output file it appears as though the BEAM command
> was never read. When I look through the EVENTDAT output file I see
> Event # 1
> Primary Weight 1. Primary Energy 199.063934 GeV
> even though I specified an energy of 150 keV.
> Does anyone know what I am doing wrong?
> Thanks,
> Jeremy Northum
> Texas A&M University
Received on Fri Apr 09 2010 - 11:03:53 CEST

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