Thanks for your reply @ctheis and also for sharing the paper! I also appreciate your advice on the Co-60 generation pathway. So certainly, my next step is to evaluate the activation with a more realistic beam shower and with the actual yoke geometry.
However, now knowing the dominant pathway to Co-60 is through trace Co in this case, I am still curious about my original question:
Of course, one will have difficulty finding pure Fe (100%) in reality, but I re-ran my input file with a pure Fe target and find no Co-60 scored by RESNUCL. I see plenty of Co-55 through Co-58 and also plenty of neutrons from a simple USRTRACK scoring, so my (crude) answer to my own question at the moment is “No” or “Maybe if I run many more primaries”. Can you or a colleague shine any light on this? Thanks!
By the way, I like the abbreviations used for ETM and DTM in the paper, which are much easier to say than the full phrase.
such multi-generation reactions are exotic in real nature and as such very difficult to reproduce with a Monte Carlo simulation where you maybe use 1e6 to 1e8 primaries which is only a tiny fraction of the particles we would expect to impinge in real life on a magnet yoke.
For radiological characterization at CERN we are also using the ActiWiz code for which is partially based on FLUKA data for high energy reactions and where we invested ~100 CPU years. There I actually see that we get some Co-60 and Co-60m (which will decay into the ground state) from pure iron. Yet the uncertainty is still very high which is not really surprising.
To give you an idea if I run a typical spectrum that we see in a magnet yoke after losing a 1.4 GeV proton beam, assuming 100% iron, 15 years of irradiation and 12 years of cooling:
Ti 44 8.905037e-11 +/- 0.41%
Co 56 1.239095e-26 +/- 0.13%
Co 57 6.018493e-16 +/- 0.98%
Co 58 1.344835e-30 +/- 2.22%
Co 60 1.494333e-15 +/- 43.40%
So you can see that in principle the model of FLUKA is capable of treating these exotic reactions but it comes at a very high computational cost and usually they are overshadowed by other reaction channels.
