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").

John

-----Original Message-----
Sent: 11 April 2013 13:16
To: systemsafety_at_xxxxxx Subject: Re: [SystemSafety] Solar Storms and Charging Procedures for Electric Cars ...



If you are not the intended recipient, please notify our Help Desk at Email isproduction_at_xxxxxx immediately. You should not copy or use this email or attachment(s) for any purpose nor disclose their contents to any other person.

NATS computer systems may be monitored and communications carried on them recorded, to secure the effective operation of the system.

Please note that neither NATS nor the sender accepts any responsibility for viruses or any losses caused as a result of viruses and it is your responsibility to scan or otherwise check this email and any attachments.

NATS means NATS (En Route) plc (company number: 4129273), NATS (Services) Ltd (company number 4129270), NATSNAV Ltd (company number: 4164590) or NATS Ltd (company number 3155567) or NATS Holdings Ltd (company number 4138218). All companies are registered in England and their registered office is at 4000 Parkway, Whiteley, Fareham, Hampshire, PO15 7FL.




The System Safety Mailing List
systemsafety_at_xxxxxx Received on Thu Apr 11 2013 - 15:14:03 CEST

This archive was generated by hypermail 2.3.0 : Tue Jun 04 2019 - 21:17:05 CEST