Measurements of cosmic ray heavy nuclei at supersonic transport altitudes and their dosimetric significance

A review is presented of cosmic ray data with special regard to heavy nuclei, the interactions of heavy nuclei with matter and the radiobiological significance of low energy nuclei. The flux of the heavy nuclei in the upper atmosphere was measured by balloon-borne plastic stacks which were flown several times at 40 g cm−2 residual atmosphere for a total time of 25 hr. From these measurements and from theoretical investigations the probabilities for hits of stopping nuclei per cm3 of tissue for SST-flights at different altitudes are derived.