|Message: photoneutron kinetic energy spectrum is wrong||Not Logged In (login)|
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I shoot 30 MeV electrons in a natural Pb target, where the electrons produce energetic gammas. The gammas then undergo (gamma,n) reactions on Pb isotopes producing the so called photoneutrons. I record the kinetic energy of the generated neutrons using StackingAction. This shows a peak around 5 MeV and a rise toward low-energies (photoneutron_geant4.png), however the experiment shows a peak around 1 MeV with decreasing intensity to low energies, which is more or less reproduced by FLUKA and MCNP (exp_fluka_mcnp.png). Why, do you think, there is such a big difference for Geant4?
Attachment: http://hypernews.slac.stanford.edu/HyperNews/geant4/get/AUX/2012/06/15/06.17-81012-photoneutron_geant4.png http://hypernews.slac.stanford.edu/HyperNews/geant4/get/AUX/2012/06/15/06.17-44668-exp_fluka_mcnp.png
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