Am-Be neutron source definition

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.

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.

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

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] )
    • 50% neutron
      particle_code = 8
      momentum_energy = sample_spectrum_momentum_energy( [filename], [unit] )
      end if

Hope this helps,

1 Like

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/ 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.



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


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