BS IEC 62396-5:2014

Process management for avionics. Atmospheric radiation effects. Assessment of thermal neutron fluxes and single event effects in avionics systems | Status: Current

1 Scope The purpose of this part of IEC 62396 is to provide a more precise definition of the threat that thermal neutrons pose to avionics as a second mechanism for inducing single event upset (SEU) in microelectronics. There are two main points that will be addressed in this part of IEC 62396:

1. a) a detailed evaluation of the existing literature on measurements of the thermal flux inside of airliners, and
2. b) an enhanced compilation of the thermal neutron SEU cross-section in currently available SRAM devices (more than 20 different devices).

The net result of the reviews of these two different sets of data will be two ratios that are considered to be very important for leading to the ultimate objective of how large a threat is the SEU rate from thermal neutrons compared to the SEU threat from the high energy neutrons (E >10 MeV). The threat from the high energy neutrons has been dealt with extensively in the literature and has been addressed by two standards (IEC 62396‑1 in avionics and JESD89A[1]1 in microelectronics on the ground). Neutrons with E > 1 MeV are considered for parts with geometries below 150 nm.

NOTE Reference is made to IEC 62396‑1:2012, 5.3.2, for smaller geometry parts below 150 nm which provides the neutron flux for energies above 1 MeV.