Radiation hardening electronic components
systems resistant ionizing radiation, high
outer space, high-altitude flight, around nuclear
reactors , particle accelerators, during nuclear
accidents or nuclear warfare.
A single charged particle can knock
thousands of electrons loose electronic
noise, signal spikes
Digital circuits inaccurate or
serious problem artificial
satellites, spacecraft, military
aircraft, nuclear weapons.
radiation belts satellites
residual radiation from isotopes
in chip packaging materials
cosmic radiation spacecraft, highaltitude aircraft
nuclear explosions military and
Cosmic rays 85% protons, 14% alpha particles, and
1% heavy ions particles 108 and
2*1010eVatmosphere filters primarily a concern
for spacecraft, high-altitude aircraft.
Solar particle events sun large flux of highenergy (several GeV) protons, heavy ion, x-ray
radiation belts electrons(10
MeV) protons (100s MeV)
in geomagnetic field.
particle flux in the regions farther
from the Earth actual conditions of
the sun and the magnetosphere.
to their position they pose a
concern for satellites.
Hardened chips manufactured
on insulating substrates Silicon dioxide
(SOI) and sapphire(SOS)
Normal commercial-grade chips withstand
50 and 100gray (5 and 10 krad)
space-grade SOI and SOS chips can survive
doses many orders of magnitude
greater4000 series chips were available in
Error correcting memory additional parity
bits to check possibly correct corrupted data.
radiation effects damage memory content
even when system is not accessing the
RAMa "scrubber" circuit must continuously
sweep the RAM reading out the
data, checking the parity for data errors
then writing back any corrections to the RAM.
Redundant elements can be used at the
3separate microprocessor boards
independent compute an answer to a
calculation and compare their answers.
Any system with minority result will
recalculate. Logic added if repeated errors
occur from the same system, that board is shut
Hardened latches may be used.
watchdog timer hard reset of a system
unless some sequence done indicates the
system is alive write operation from an on
normal operation software schedules a
write to the watchdog timer at regular
intervals to prevent the timer from running
If radiation causes the processor to operate
incorrectly the software will work correctly
enough to clear the watchdog timer.
The watchdog times out, forces a hard
reset to the system a last resort to other
methods of radiation hardening.
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