Hello,
I would like to know which physics list is the most accurate (meaning regardless of CPU time) regarding photonuclear cross-section and processes for photons energies of approximately 20 MeV. It seems most physics lists are using the Bertini cascade model for photons below 3 GeV. I have seen other lists using INCLXX (INCL++ model). Are these models comparable in terms of accuracy? Is there anything else I should consider?
Also, I believe the accuracy for neutron thermalization can be improved with the “_NP” option. Does this option has any effect on photonuclear reactions?
Many thanks.
I have been using the Shielding_LEND physics list for photoneutron studies <= 20MeV. Neutron production rates, where I had data for comparison, were of the same order of magnitude as experiment, but spectral shapes were not a good approximation to reality. (See photoneutron process is inaccurate at low gamma ray energy.) I tried three other physics lists (QBBC, QGSP_BIC_HP, Shielding). They had the same rates and spectral shapes as each other, which were different from those of Shielding_LEND. However, their rates and shapes were no closer to experiment than Shielding_LEND.
So in short, for me it’s hard to say what is the best choice. I’ll let the experts jump in this one.
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Dear John,
Thanks for your comment. Indeed reading about the LEND physics list, I think it’s supposed to be more accurate for low energy neutrons than alternatives. Without knowing the details of each it’s difficult to make your mind. Like you did I will see how each compares with my data.
Can You pin here Shielding_LEND.cc file please ?
The latest distribution (11.1.2) has ShieldingLEND.hh at /pathto/geant4/geant4-v11.1.2/source/physics_lists/lists/include/ShieldingLEND.hh. There is no corresponding ShieldingLEND.cc file in /pathto/geant4/geant4-v11.1.2/source/physics_lists/lists/src .