Neutron and proton measurements of OSO-6 near the South Atlantic radiation anomaly

The University of New Mexico High-Energy Neutron Experiment flown aboard NASA Satellite OSO-6 in 1969 was designed and built to study neutrons at an altitude of approximately 500 km, above the earth's dense atmosphere. The detector was a proton recoil telescope with directional discrimination and was sensitive to protons as well as neutrons. Neutron data from August, 1969 to January, 1971 was analyzed in the energy range 40-120 MeV. Proton data in the energy range 60-170 MeV obtained during October and November of 1969 was also analyzed. Analysis was limited to the region of space known as the South Atlantic Radiation anomaly. This investigation was carried out to study source and loss mechanisms of the Van Allen radiation belts. The omnidirectional proton flux as a function of B and L at approximately 500 km altitude in the anomaly (latitude limit --330) was presented. Results in the 200-400 km minimum mirroring altitude range gave good agreement with previous effective atmospheric loss computations indicating that coulomb interactions are the prime loss mechanism for inner belt protons. Results in the 400-500 km minimum mirroring altitude range indicated possible problems with the high altitude constituents of the model atmospheres considered here. The east-west ratios of the neutrons near the anomaly indicated that more neutrons are being generated in the anomaly than elsewhere. These additional neutrons are most likely being produced by high-energy trapped protons colliding with the atmosphere in the anomaly