The spatial distribution of irradiation damage spots

Abstract

The fine-scale damage spots observed in thin foils of neutron irradiated copper do not always appear to be entirely randomly distributed, showing in particular some apparent lining up of spots. A digital computer has been used to determine the number of linear triplets of spots in both a foil and a series of random arrays, the results being displayed pictorially by an electronic graph plotter. No significant difference between the results for the foil and the random arrays was found. The near randomness of the spots was confirmed by counts of the density distribution function for two foils, which both showed almost a Poisson distribution.

It is concluded that the apparent “structure” in the distribution of the irradiation damage spots is wholely compatible with that of random arrays. This result may have general implications in other branches of metallography.