Correlation of Meteorological Parameters with Cosmic-Ray Neutron Intensities

The correlation of variations in the neutron intensity of cosmic radiation with variations in meteorological conditions has been investigated at 6262 ft and at sea level over the period from 1952 to 1955. A low-energy directional neutron detector was operated during the summer months of this period to monitor the intensity of neutrons with energies less than 0.5 ev. In addition a lead-paraffin pile detector was used to monitor the moderate energy neutrons.From the partial correlational analysis for the low-energy neutron intensity the following regression coefficients are obtained: barometric pressure (-10.9±{}0.9) percent/cm Hg; specific humidity (-2.0±2.5)%0.01S, where S is the local specific humidity; local atmospheric temperature (-0.07±{}0.09)%/F^∘{}. For the moderate-energy neutron detector the only significant regression coefficient obtained is for barometric pressure, α=(-9.70±0.15)%cm Hg. The results for the dependency of neutron intensity upon barometric pressure and temperature are in agreement with the predicted values, but the results for the specific humidity correlation do not agree with the theoretical predictions. The significance of the latter result is discussed.Experiments have also been made to determine the energy spectrum of low-energy neutrons at ground elevations by using paraffin moderators of different thicknesses placed over the low-energy directional neutron detector. The observed proportion of neutrons with energy exceeding 0.6 ev is less than predicted theoretically.