The energy dependence of the cosmic-ray neutron leakage flux in the range 0.01-10 Mev

Abstract

The cosmic-ray neutron leakage flux and energy spectrum in the range 1–10 Mev were measured by a neutron detector on the Ogo 6 satellite from June 7 to September 30, 1969. The same detector simultaneously measured the total leakage flux, having 75% of its response to the leakage flux in the interval 1 kev to 1 Mev. For a neutron energy spectrum of the form AE−γ in the range 1–10 Mev, the upper limit to γ for polar regions (Pc⪕0.3 Gv) was found to be 1.0 and for the equatorial regions ( Pc⪖12 Gv) was 1.2. For the polar regions, the lower limit to γ was found to be 0.8. This energy spectrum at 1–10 Mev is slightly flatter than L. L. Newkirk predicted. The neutron fluxes at 1–10 Mev were 0.28±0.03 and 0.035±0.003 cm−2 sec−1 for Pc⪕0.3 and Pc⪖12 Gv, respectively. The ratios of the neutron flux at 1–10 Mev to the total neutron flux were 0.54±0.07 for Pc⪖0.3 Gv and 0.50±0.06 for Pc>12 Gv.