Re: [SystemSafety] Solar Storms and Charging Procedures for Electric Cars

From: SPRIGGS, John J < >
Date: Thu, 11 Apr 2013 13:13:43 +0000

Peter Ladkin said, inter alia:
> At least some people in the avionics community have argued that SEUs in commercial
> aircraft at cruise are likely mainly to be neutrons (that was the suggestion that raised
>the scepticism of my particle-physicist colleagues).

I think the argument is that charged particles can be stopped by a fairly thin piece of metal, e.g. the avionics box itself, but a free neutron can pass through. So, if you have "cosmic rays" in there, they "are likely mainly to be neutrons".

Being neutral, a neutron should not be a problem; but free neutrons are more likely to decay into charged particles than ones in atomic nuclei. So, if you have a charged-particle-triggered "upset" inside your metal enclosure, it is more likely to be due to a neutron decay product than a charged particle per se. That said, I agree with the particle physicists, "more likely" still means rare.

Where are these free neutrons supposed to originate? If they come all the way from the sun, they may be ripe for a decay event inside your avionics box, but if they come from some effect of a solar storm on the atmosphere, such a decay is unlikely (unless they are moving slowly - and we do not know the "spectrum").


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