Albedo Neutron Component of the Earth's Radiation Environment

摘要

A high energy neutron detector has been constructed to measure the solar neutron flux, under quiet or active Sun conditions, over the energy range 10 MeV to 200 MeV. The detector consists of a plastic scintillator (the central detector) with anticoincidence shield. The central detector is surrounded by an Aluminum sheath, whose purpose is to bring to rest the recoil protons, thus diminishing the self-gating effects and keeping the detection efficiency high enough at high energies. No finite flux has been however detected and an upper limit of 0.0055N/sq. cm. has been established for the continuous flux, which is comparable (although somewhat lower) with other upper limit of 30N/sq. cm. is established for a 1N importance optical flare. Also the omnidirectional intensity of atmospheric gamma rays, converted in the Aluminum sheath, has been measured at ballon altitudes at three energy levels. A value of 0.33/sq. cm. sec has been found for energies greater than 20MeV. The results are in good agreement with those obtained by Fichtel et al.(1969). (Author)