Single-event latch-up (SEL)
Beginner
A particle hit opens a hidden short circuit inside the chip. Too much electricity flows, and it can burn the chip out.
Novice
A particle strike switches on an unintended path through the layers of silicon in a chip, letting a large current flow from the power supply to ground. It stays on until the power is removed and can destroy the chip.
Expert
The unintended path is a parasitic thyristor formed by neighboring n- and p-type regions. Specified as an LET threshold below which latch-up must not occur (for example above 125 MeV·cm²/mg). Countered by the process (silicon-on-insulator is inherently immune), guard rings and well taps in layout, and current limiting with power cycling in the system.
Explained in Space (Industries).