Cyclotron-based production of Gallium-68

Good day FLUKA community,

I am working now on the cyclotron-based production of Ga-68. I am simulating the irradiation of a target made mainly of Zinc-68 with protons. From other experimental results for a case they got 36.6 GBq, replicating their conditions with FLUKA I got 26.9 GBq, and using TALYS I got 34.8837 GBq.

Please, any explications for this? is the proton cross-section of the Zn-68 reaction included in FLUKA?

Thank you.

Dear Luis,

Thanks for your post.

Is the proton cross-section of the Zn-68 reaction included in FLUKA?

Note that FLUKA does not rely on an integrated cross section channel by channel for nuclear inelastic interactions. Instead:

  • The proton reaction cross section in FLUKA is parametrized as a function of the primary energy and the target nucleus. This is the quantity used by the code to decide how often to perform a nuclear inelastic interaction.

  • Once a nuclear inelastic interaction takes place, the actual reaction channel is internally sampled/decided by FLUKA’s model for hadron-nucleus inelastic interactions.

Please, any explications for this?

Behold the following plot:

It displays the integrated cross section in mb for the reaction 68Zn(p,n)68Ga as a function of the proton energy in MeV. The various red symbols are all datasets extracted from EXFOR for this channel and the blue curve is the FLUKA result at production level.

Note the overall good agreement in a considerable energy domain between experimental data and FLUKA, expecially if you take into account the uncertainty among the various datasets. The position and intensity of both the onset and the maximum are especially well reproduced.

However, it is true that there is an energy window past the maximum, say between 15 MeV and 25 MeV, where FLUKA tends to underestimate a bit the resulting cross section for this channel (more or less depending on the dataset you wish to pick). We assume that this is precisely the energy range you’re looking at (otherwise, please let us know).

This seems to be indirectly supported by the measurements you report (are they published and, if so, do you have the reference?). Since these measurements seem to validate the (otherwise very localized)
underestimation, this could warrant a further look for fine tuning in the future on our side.

With kind regards,


A post was split to a new topic: Study of Ga-68 yield