Hi, I have to do a post-irradiation diagnostics for electronics damage and identify whether neutrons, protons or heavy-ions caused the main damage on the electronics. Regarding DDD, some manuals and papers mention the use of SI1MEVNE and others mention NIEL-DEP and DPA.
1- Would only SI1MEVNE work for non-standard silicon media and can it be used to identify heavy-ions?
The proton dataset is used for all other baryons and antibaryons, including ions.
So I was wondering, is AUXSCORE still enough to differentiate heavy-ions from protons?
3- I am wondering your thoughts in general, would NIEL-DEP be enough for DDD standalone with no need to DPA USRBIN?
Which scoring should be preferred along with AUXSCORE card to identify the mainly effective radiation type regarding DDD? Also, I would appreciate any other comments or help regarding radiation damage on electronics study. Thank you so much!
in fact, displacement damage is due to recoiling nuclei (‘heavy ions’). In the simulation, the attribution to the latter ones or to the particle inducing the interaction generating them, depends on the heavy ion transport threshold (that in FLUKA is set based on the 4-HELIUM one). Hence, such a distinction is rather arbitrary, similarly to what happens for energy deposition (in fact, energy deposition is due to electrons, but in the simulation it’s attributed to the parent particle when secondary electrons are not explicitly generated).
Therefore, if you are interested in displacement damage in silicon, I’d suggest you use USRBIN with SI1MEVNE - to get the (equivalent) fluence of 1 MeV neutrons producing the same displacement effect - without AUXSCORE filtering. The alternative, to be necessarily applied to other materials, is the use of USRBIN with DPA-NRT and/or ARC-DPA - to get directly the number of displacements per atom (again without AUXSCORE). Then, to identify which are the radiation types responsible for the damage, an independent fluence scoring by USRBIN may serve the purpose, better than the rather arbitrary and so possibly misleading AUXSCORE filtering of the damage related quantity (SI1MEVNE, DPA-NRT, ARC-DPA).
Sorry, I think I missed the part, for this case a heavy-ion beam (U-238 with ~500 MeV specifically) was used. And I am using HI-PROPE card to specify that in the simulation. So, I am trying to distinguish the effects of primary heavy-ions and secondary protons and neutrons (and other products). Should I still follow the same approach to eliminate the misleading results originating from the reasons you have mentioned?
Also, for example, fluence of neutrons after hitting the target is much higher than protons but the DOSE of protons is greater than neutrons in my scored region, somewhat expected due to high energy neutrons. So, by applying filtered fluences (neutrons, protons, heavy-ions, photons etc.) to total results from SI1MEVNE or DPA-NRT, can I get misleading results again due to a similar reason to DOSE example? Thank you for your time.
My point is that recoils generated by nuclear interactions of secondary protons and neutrons may not be accounted for in the proton and neutron contributions, rather in the heavy ion one if they are transported by FLUKA being above the transport threshold (that is 25 keV/n by PRECISIO DEFAULTS). You may want to evaluate the evolution of the respective contributions - obtained by AUXSCORE filtering - as a function of the latter (you can change with PART-THR applied to 4-HELIUM).
I understand you mean to score SI1MEVNE and DPA-NRT without filtering and to look in parallel at fluences of different particle types, as I suggested above. One has indeed to be careful: as you pointed out, a high neutron fluence in a region does not imply that the DOSE deposited there is mostly due to neutrons (since other particle types are much more effective in depositing dose). Analogously, a high electron or photon fluence unlikely translates into a dominant contribution to displacement damage (which is rather ruled by hadrons).