Advice Needed on Fission Fragment Yields for Pu-239 and Coupling GEF with Geant4

Physics Processes, Models and Cross Sections
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_Geant4 Version:_11.3.0
_Operating System:_Ubuntu
_Compiler/Version:_gcc
_CMake Version:_3.22.1

Hello everyone,

I am currently working on a Geant4 simulation to model a fission chamber, and I need to simulate the production of fission fragments, particularly for Pu-239.

I would like to ask the community for advice on the following:

  1. Fission fragment yield data for Pu-239: Does anyone have experience obtaining fission fragment yield data for Pu-239 from JEFF3.3 database that can be used directly in Geant4? Moreover, I would like to know if the existing fission yield data are:
  • Interpolated between measurements at different neutron energies, or
  • If the yields are assumed to be constant across different energies.
  1. Coupling Geant4 with GEF: Alternatively, I am considering coupling Geant4 with the GEF (General Description of Fission Observables) code to generate fission fragment yields myself. Has anyone here successfully integrated GEF with Geant4? If so, I would greatly appreciate any guidance on:
  • How to extract and format the output from GEF for use within Geant4.
  • Any recommended tools, scripts, or strategies to facilitate this coupling.
  • Any common pitfalls or challenges I should be aware of during this process.
    Any insights, suggestions, or resources would be highly appreciated. Thank you in advance for your help !
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I havn’t try to combine GEF to the Geant4 but I tried to use the ENDFVIII data to let Pu239 produce the fission products. You just need to download the JEFF fission products data and using the txt format to record it. Just like this file ,this is the ENDFVIII data I download form the www-nds.iaea.org. I have already change it to the G4NDL format. You just need to put it in the your nuclear data location\G4NDL4.7.1\Fission\FF. and you can use it !
Don’t forget use “G4ParticleHPManager::GetInstance()->SetProduceFissionFragments(true);”to produce the fission products.

94_239_Plutonium.txt (207.9 KB)

1 Like
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First of all thank you very much for your answer !

Meanwhile I managed to combine GEF with Geant4 but I’m using GEF output in “list mode” (each fission products are written for every simulated fission event), which is not as clean as your solution I think.

With your answer I’m now considering using the GEF output, not in list mode, but process them to generate files in the G4NDL format in order to have fission yields with a more precise energy dependance. Do you know any ressource/documentation concerning the G4NDL format ?

I understand from your .txt that the first and fourth column is “ZZAAA”, the third and sixth the yield, but what does the second and fifth columns stand for ? is it an isomeric state designation ?

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Yes,the second and fifth columns are stand for isomeric state designation. 0 represents the ground state, and 1 represents the excited state. For specific information, you can refer to the ENDF data format for determination.