Support for Crand Theory from measurements of Earth albedo neutrons between 70 and 250 MeV

Abstract

The results of high energy neutron measurements during two balloon flights on May 1 and 25, 1971, from Palestine, Texas, are reported. At atmospheric depths of 8.6 and 4.7 g cm−2 we obtained the energy and angular distribution of atmospheric neutrons between 70 and 250 MeV. The upward moving part, in terms of the albedo neutron leakage current, can be described by J2π=2.53 · E−1.89 neutron/cm² s MeV in this energy range. The angular distribution of the neutron flux shows a pronounced peak in the horizontal direction (zenith angle, 90°) with a full width at half maximum of about 30°. The measured energy spectrum is in good agreement with results of recent Monte-Carlo calculations on atmospheric neutrons. Together with the angular distribution it also confirms theoretical estimates of the albedo neutron source strength required in a Crand (cosmic ray albedo neutron decay) theory where the high-energy protons in the earth's inner radiation belt are injected by decaying neutrons. The instrument used employs a double scattering technique and has been calibrated at the synchrocyclotron of the Atomic Energy Research Establishment, Harwell, England.