An experimental study of the isotopic composition of cosmic ray nitrogen and oxygen

An investigation of the isotopic composition of cosmic ray nitrogen and oxygen has been made. As a detector nuclear emulsions exposed in 1970 in a balloon flight from Fort Churchill have been used. The mass determinations are made on particles stopping in the emulsion stack and are based on the relations between residual range and track width measured with a nuclear track photometer. The results extrapolated to the top of the atmosphere are 15N/(14N+15N) =0.30+-0.11; ( 17O+18O)/(16O+17O+18O) =0.10+-0.05. (Auth.)