Re: Photon Beam Energy

Dear Jeremy and Giuseppe,

Using the PRECISIO default in this case is overkill (I am fighting a long
battle against the preference for this default that most users are
showing even although in most cases it is not necessary).
The obvious choice for a 150 keV photon beam is EM-CASCA.
Still, setting both production and transport energy cuts with EMFCUT
will be necessary.

Alberto

On Fri, 9 Apr 2010, Giuseppe Battistoni wrote:

> 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
>
>

-- 
Alberto Fasso`
SLAC-RP, MS 48, 2575 Sand Hill Road, Menlo Park CA 94025
Phone: (1 650) 926 4762   Fax: (1 650) 926 3569
fasso_at_slac.stanford.edu