Anomalous increase in the neutron flux at aircraft altitudes

Abstract

An anomalous increase in the flux of low-energy neutrons (0.02 ev to ∼5 Mev) was detected at aircraft altitudes on January 21, 1964, between 0350 and 0400 UT. The aircraft (at an altitude of 39,000 feet and a geographic position between 38° and 35°S latitude in the region of the magnetic anomaly east of Buenos Aires) was instrumented with ionospheric sounding gear, three cosmic-ray neutron counters, and night airglow monitors. The increase in the neutron flux, which was detected by all three neutron counters, coincided with an increase in the intensity of the night airglow monitored in the same aircraft.