Intensity of the Soft and Hard Component of the Cosmic Radiation as a Function of Altitude at Geomagnetic Latitudes of 28°N, 41°N, and 55°N

Counter telescopes have been flown with plastic balloons to a maximum altitude of 94,000 ft. Intensity $\mathrm{vs}$ pressure curves have been obtained at geomagnetic latitudes of $\lambda ={55}^{\circ },{41}^{\circ }, \mathrm{and} {28}^{\circ }$ for the total cosmic radiation and for the components capable of traversing several thickness of lead. The energy spectrum of primary cosmic-ray particles has been derived from the extrapolation of the intensity of the total radiation to the top of the atmosphere. The integral momentum spectrum of the total primary radiation is given by $N(>\mathrm{}\frac{\mathrm{pc}}{\mathrm{Ze}})=0.49\mathrm{}{\left(\frac{\mathrm{pc}}{\mathrm{Ze}}\right)}^{-1.0\mathrm{}}$. The results show that the radiation originating from primaries in the energy range 1 to 4 Bev (cut-off energies at $\lambda ={55}^{\circ } \mathrm{and} {41}^{\circ }$) is predominantly of a nucleonic nature. The absence of an appreciable electronic component can be explained by assuming that, close to the top of the atmosphere, electrons originate predominantly from the decay of neutral mesons and that, within this energy range, the over-all probability of nucleon emission is greater than that of meson production. In sharp contrast, the soft component originating from primaries in the range from 4 to 8 Bev (cut-off at $\lambda ={41}^{\circ } \mathrm{and} {28}^{\circ }$) multiplies rapidly in the atmosphere. This large transition effect in air with a maximum at about 10 cm Hg pressure is very characteristic of electron showers. It is concluded that the probability of neutral mesons being produced is comparatively high at primary energies between 4 and 8 Bev. At energies higher than 8 Bev this effect is even more pronounced, due to the contribution of the plural and multiple production of mesons.