Abstract
In an analysis of cosmic ray stars found in Ilford G5 emulsions exposed at about 85,000 ft. the star-size distribution curve shows a change in slope at a prong number of about 8.5. A similar effect is shown for emulsions exposed at airplane altitudes, and it is assumed that the effect is mainly due to the composition of the emulsions. While the primary particles producing the stars at about 85,000 ft. are mostly protons, about 50% of the low energy stars are produced by nonionizing radiation, presumably neutrons. a-Particles and heavier nuclei produce about 30% of the larger energetic stars. The absolute frequency of star production is given.
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