Neutron-Induced Single-Event Effects
High-energy neutrons cause upsets indirectly through nuclear recoils; a 14 MeV source is a direct way to reproduce this dominant terrestrial failure mode.
The indirect ionizer
Because neutrons are uncharged, a neutron-induced single-event effect always proceeds through a nuclear reaction. The neutron strikes a silicon or dopant nucleus, and the charged reaction products deposit the ionizing energy. This indirect path is why neutron SEE rates depend strongly on neutron energy: higher energy opens more reaction channels and produces more energetic secondaries.
Why 14 MeV is a strong probe
A 14 MeV neutron sits above the thresholds for many reactions that lower-energy neutrons cannot trigger. That makes it effective for exposing worst-case upset behavior and for accumulating statistics quickly. It also aligns with the hard tail of the atmospheric neutron spectrum, which dominates soft-error rates in avionics and high-altitude systems.
- Reactions produce alpha, proton, and heavy recoils
- Secondaries carry the linear energy transfer that upsets nodes
- Higher energy yields higher and more varied event rates
From beam to specification
A campaign exposes a powered device to a known 14 MeV fluence while logging every upset, then reports the SEE cross-section, upsets per unit fluence. That number feeds system-level error-rate predictions for the environment the hardware will operate in.
Building upset statistics
Because a single-event upset is a probabilistic event, meaningful cross-sections require many events, and that in turn requires substantial fluence. A strong, steady 14 MeV source shortens the time needed to accumulate the statistics that make a cross-section trustworthy. It also lets rare, high-consequence events, such as destructive latch-up, be searched for with enough exposure to bound their probability rather than merely note their absence in a short run.
This is a public overview only. It contains no classified information, no operational detail, and no weapons-design content.