Am-Be neutron source definition

[mohammed.fayiz (Mohamed Fayez-Hassan)]

Dear Colleague and Experts

1- Am-Be neutron source can have about 50% neutron (thermal and fast ) and 50% gamma ray fields.How we can describe both complex fields in one time in FLUKA.

• DOI:
• 10.1016/j.apradiso.2007.04.007

2- in previous Mihaela Parvu advised me to used source_newgen.f for two gamma source. In this current case how can I use the same technique.

Advance Multiple- complex Radioactive source

Hello, I strongly suggest using the source_newgen.f file instead of the source.f one. For example, if you want a beam with 50-50 Co-60 and Ba-133: double precision, save :: choose_isotope choose_isotope = FLRNDM (xdummy) radioactive_isotope = .true. if (choose_isotope < 0.5) then heavyion_atomic_number = 27 heavyion_mass_number = 60 else heavyion_atomic_number = 56 heavyion_mass_number = 133 end if The photon spectrum will look like this: [image] I have also attac…

3- Also I read in FLUKA User Forum articles about the source spectrum text input, where I can read to have a full experience about this advanced topic?
Best Regards
Fayez

[Mihaela_Parvu]

Dear Fayez,

Please take a look at the last two lectures of the day - Source routines.
Starting with FLUKA 4-3.0 release, if you know the neutron and photon spectra, you can use spectrum sampling.
For example:

  ! 3.4.5. Sampling from spectrum
  ! ------
  !    Possible [unit]s: "TeV",   "GeV",   "MeV",   "keV"    "eV"
  !                      "TeV/c", "GeV/c", "MeV/c", "keV/c", "eV/c"
  !                      "J"
  !    Spectrum file has to have 2 columns:
  !       - Energy
  !       - Intensity

•  momentum_energy = sample_spectrum_momentum_energy( [filename], [unit] )
   
   double precision, save :: choose_part
   choose_part = FLRNDM (xdummy)      
  

  • 50% photon
    if (choose_part < 0.5) then
    particle_code = 7
    momentum_energy = sample_spectrum_momentum_energy( [filename], [unit] )
    else
  • 50% neutron
    particle_code = 8
    momentum_energy = sample_spectrum_momentum_energy( [filename], [unit] )
    end if

Hope this helps,
Mihaela

[horvathd (Dávid Horváth)]

Unfortunately the solution Mihaela is proposing won’t work out of the box, as the sample_spectrum_momentum_energy function will only read the first file passed to it.

The workaround is to duplicate the function (located in the incude/source_library.inc file) with a different name and use that for the second spectrum.

The feature to read multiple spectrum/histogram files is planned for a future release.

Cheers,
David

[mohammed.fayiz (Mohamed Fayez-Hassan)]

Thank you Mihaela Parvu for the detailed methodology. I will try to implement your suggestions taking into account Dr. Dávid Horváth advice as well.

Regards,
Fayez

[mohammed.fayiz (Mohamed Fayez-Hassan)]

Sincere thanks and appreciation Dávid Horváth for the complete clarification which will direct us to the desired results.
Best Regards
Fayez