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Volume 40, Number 1, 1996
Terrestrial cosmic rays and soft errors |
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Table of contents:  HTML |
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Copyright info |
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Terrestrial cosmic rays |
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by J. F. Ziegler |
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This paper reviews the basic physics of those cosmic rays which can
affect terrestrial electronics. Cosmic rays at sea level consist mostly
of neutrons, protons, pions, muons, electrons, and photons. The
particles which cause significant soft fails in electronics are those
particles with the strong interaction: neutrons, protons, and pions. At
sea level, about 95% of these particles are neutrons. The quantitative
flux of neutrons can be estimated to within 3×, and the relative
variation in neutron flux with latitude, altitude, diurnal time, earth's
sidereal position, and solar cycle is known with even higher accuracy.
The possibility of two particles of a cascade interacting with a single
circuit to cause two simultaneous errors is discussed. The terrestrial
flux of nucleons can be attenuated by shielding, making a significant
reduction in the electronic system soft-error rate. Estimates of such
attenuation are made.
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