What is cross section? (Correlation between incident neutron and proton for Single Event Upset (SEU))

I recently came across the following in the paper below: “GEANT4 simulations… show(ing) also that neutron and proton SEU cross sections are compatible above 20 MeV

I would like to clarify since I don’t have a physics background: what is meant by cross section here? Does it refer to the area within which an SEU occurs? Alternatively, I read elsewhere that cross section itself is a probablity. Does that mean that incident protons > 20 MeV can be used instead of neutrons at that energy to study the effect of SEUs?

Reference: M. Cecchetto et al ., “0.1–10 MeV Neutron Soft Error Rate in Accelerator and Atmospheric Environments,” in IEEE Transactions on Nuclear Science , vol. 68, no. 5, pp. 873-883, May 2021, doi: 10.1109/TNS.2021.3064666. 0.1–10 MeV Neutron Soft Error Rate in Accelerator and Atmospheric Environments | IEEE Journals & Magazine | IEEE Xplore

Cross section is a type of probability used to calculate absorption, scattering, or just total attenuation. The macroscopic cross section is basically the same as an attenuation coefficient.

I do not know this paper (and sorry not time to read it today). However, let me clarify what is a SEU cross section. It is the number of SEUs divided by the number of incident particles (usually) per cm^2. Therefore, the unit of the SEU cross section is cm^2.


The concept of cross section of SEU comes from nuclear physics, and it is truly means the probability of SEU happening. About your second question, I think it is according to specific situation, it depends on microelectronic device, and in Standard JESD89A, engineers indeed think protons above 50 MeV can substitute neutrons above 50 MeV irradiation test.
Best wishes.

Thanks all, this was fairly helpful!