Physics list recommendation for photonuclear reactions


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.


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.