Neutron-Proton Ratio at Different Atmospheric Depths and Sea Level Neutron Spectrum Derived from the Primary Nucleon Spectrum

The differential neutron spectrum at sea level has been calculated using the conventional phenomenological model after ASHTON. The energy dependence of nucleon-air nucleus inelastic interaction cross section is assumed in these calculations. The derived sea level neutron spectrum from the satellite measured primary nucleon spectrum of GRIGOROV et al. fits well the experimental neutron spectrum of ASHTON and COATS. The neutron-proton ratios calculated for different atmospheric depths is in accord with the measured data (AGUIRRE).