Measurement of the cosmic-ray neutron flux in the atmosphere

Summary  A neutron detector, employing boron-plastic scintillator counters, and designed for the measurement of low neutron fluxes, is described. The performance of this instrument in the measurement of cosmic-ray neutron flux both at sea-level and in balloon flights is discussed. Preliminary data on the absolute flux of cosmic ray neutrons in the atmosphere and the variation of the flux with atmospheric depth are given and compared to previous and predicted values.