Fast neutron latitude variations in the atmosphere at solar minimum

摘要: The fast-neutron flux in the atmosphere has been measured during solar minimum. Data from ground level to about 4 g/cm2 were obtained a series of seven high-altitude balloon flights. flights conducted between September 1964 and August 1965 at four locations λ = 8°N 69°N, conventional geomagnetic latitude. detector, phoswich-type scintillator, was sensitive neutrons range 1–10 Mev. A seven-channel pulse-height analyzer permitted evaluation energy spectrum this range. neutron transition maximum increased 0.17±0.02 cm−2 sec−1 1.9±0.1 69°N. Neutron leakage top estimated by extrapolation. magnitudes fluxes, as well pole-to-equator ratio 16, substantial agreement with results diffusion calculation Lingenfelter. best fit an inverse power law differential found be independent latitude within limits our experimental precision. Averaged over all flights, for special index n 1.05 ± .15. This is harder than that calculated Differences shapes profiles experiment are consistent difference spectrum.