scope:

This document provides an example process for analyzing neutron Single Event Effects (SEE) for an electronic based airborne system for use in system safety assessments. This example has been used when the safety assessment process was in need of an SEE analysis.

PURPOSE

Galactic cosmic rays and solar rays penetrate the earth's atmosphere, and produce particle cascades. The atmospheric radiation is comprised mainly of high energy neutrons that can interact with a semiconductor device's silicon structure causing adverse behavior.

This document describes an example process to evaluate the effects of atmospheric radiation at the equipment level, based on effects on electronic circuits. Additional atmospheric radiation information can be found in other industry documents including the IEC 62396 series. This AIR is intended to support a safety analysis; there may be other uses for this SEE analysis, but these are not specifically addressed in the document. The document is not intended to define specific data formats or organizational responsibilities. There may be other acceptable approaches to supporting SEE analyses within safety assessments.

Note: this document only addresses the activities that are used for equipment level SEE considerations. Benefit from system level mitigation may be used during the system safety assessment process (ARP4761 / ED-135). For the purposes of this document, equipment is defined as any self-contained assembly composed of one or several hardware and software items that perform a distinctive function necessary to the operation of the system. This document primarily covers neutron effects, as they have the greatest impact on semiconductor device behavior in the atmospheric radiation environment.

This document does not address the following:

• Alpha particles,

• Other cosmic particles,

• Electronic noise or other electronic sources of adverse behavior