[Physics] How are neutrons produced from cosmic ray particles

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What are the details of how neutrons are produced as a result of cosmic ray particles hitting our planet's atmosphere?

For instance, what is the pathway that creates the highest number of neutrons from cosmic ray particles?

The article "Single event upset" states:

An SEU happens due to cosmic particles which collide with atoms in the atmosphere, creating cascades or showers of neutrons and protons. At deep sub-micrometre geometries, this affects semiconductor devices at sea level.

But it does not describe the mechanism.

The Wikipedia article on the neutron states something similar:

Cosmic radiation interacting with the Earth's atmosphere continuously generates neutrons that can be detected at the surface.

What are the processes, in detail?

Best Answer

OK, here is something concrete and quantitative, "Guidelines for predicting single-event upsets in neutron environments":

Neutrons in the atmosphere result from cosmic-ray spallation interactions with nitrogen and oxygen nuclei. A typical reaction is a 1 GeV proton fragmenting a nitrogen necleus into lighter charged particles and simultaneoously emitting a couple of neutrons.

Cosmic ray spallation.


From "Cosmic ray induced ionization in the atmosphere: Full modeling and practical applications":

... full numerical model, which computes the cosmic ray induced ionization in the entire atmosphere, from the ground level up to the stratosphere, all over the Globe. The model computations reproduce actual measurements of the atmospheric ionization in the full range of parameters, from equatorial to polar regions and from the solar minimum to solar maximum. A detailed numerical recipe is given in section 2.5 together with the precalculated tabulated ionization yield function (Tables 1 and 2). Using this method, one can easily compute the CRII for any desired location and conditions, instead of using, e.g., a neutron monitor count rate as a proxy.

It does not describe it, but the CORSIKA (Cosmic Ray Simulations for Kascade) simulation tool is used.


Google-fu: quantitative neutrons cosmic rays atmosphere

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