Altitude and latitude effects of atmospheric neutrons

Abstract

Ilford G5 emulsions were exposed at six altitudes from 4 to 40 mbar at λ = 7.8°N geomagnetic latitude (NGL). Atmospheric neutrons of 10–200 MeV are studied using three independent parameters. Spectra at 0 mbar were obtained by extrapolation. Energy spectra for neutrons were studied for seven different altitudes from 4 to 40 mbar. Spectra at 0 g/cm² for total neutrons and the upward moving albedo are compared with the experimental and theoretical results of other authors. Atmospheric depth curves for total neutrons and albedo neutrons are given, and results are compared with theory and other experiments. A study of the latitude effect gives a variation by a factor ∼2.3 for λ = 7.8° to λ = 41°NGL for total neutrons and a little higher value of 2.5 for albedo neutrons of 10–100 MeV, in good agreement with theory and the experimental results of other workers.