Neutrons Produced in the Atmosphere by the Cosmic Radiations

The distribution of disintegration product neutrons in the atmosphere has been measured from the geomagnetic equator to 65^∘{}N and up to {~}220 g-cm^-2 air. The measured exponential absorption of the neutron producing radiations in the equilibrium portion of the atmosphere is: L(0^∘)=212, L(19^∘)=206, L(40^∘)=181, L(53^∘)=157, L(65^∘)=157 g-cm^-2. It is shown that the neutron component has the largest latitude effect of any known secondary component in the cosmic rays and that the neutrons are part of a low energy nucleonic component in the atmosphere. The yield of neutrons per incident primary particle in an air column one cm² area extending through the atmosphere has been calculated at various latitudes. The yield increases by 400 percent between 0^∘{} and 55^∘{}N. The slow neutron absorption in air at the geomagnetic equator under 312 g-cm^-2 air was measured. It is concluded that nucleon collision chains in the atmosphere are the principal process by which a low energy nucleonic and neutron component is produced. Measurements at high latitudes over a period of two years have shown that fluctuations and large changes of intensity of the neutron component may occur during solar and terrestrial disturbed days.