Dear FLUKA (and residual nuclide activation) experts,
I am investigating the activation of high purity iron (99.85%) magnet yokes that were used in the past at a p+ synchrotron facility. Gamma spectrometry results of drilled cores of the magnets’ jaws show 3 key residual nuclides (after ~15 years operation and ~12 years of decay): Co-60, Ti-44, and Na-22 with approximate abundance at 15% / 70% / 15%. Other parts of the magnet show ONLY Co-60.
From the EXFOR nuclear reaction libraries, I find clues to pathways from Fe to these nuclides. Ti-44 and Na-22 are spallation products. And I believe Co-60 is generated from multiple neutron captures (n,gamma) by the Co nuclides, which are from Fe(p,x) interactions.
Now, I decide to run a simple FLUKA simulation to check residual nuclide generation. In the attached input file, I interact a 1 GeV/c p+ beam (max losses from) with a cylindrical target, which is composed of high purity iron (Armco 99.85% Fe, with the rest being trace elements). I believe I called the appropriate cards for evaporation with heavy fragments, coalescence, RADDECAY, etc. and also compiled a new executable via “ldpmqmd” with flair.
magnet.inp (7.3 KB)
From RESNUCLE scoring, I find after 15 years operation and 12 years decay that the proportions of the 3 key nuclides are 0.3% / 99% / 1.3%. To be honest, I did not expect to match what was measured with gamma spectrometry with such a preliminary analysis, but I am particularly surprised to see so little Co-60 relative to Ti-44.
With so much backstory, now my question. Is FLUKA capable of calculating Co-60 generation from my suspected pathway: Fe(p,x) --> multiple Co(n,gamma) --> Co-60? Here, it is the tertiary and even quaternary step…
Thanks for reading so far, and any advice is greatly appreciated!
Cheers!
Ted (DESY)