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.

Time dependent worldwide distribution of atmospheric neutrons and of their products: 1. Fast neutron observations

“…Figure 4b also [Simpson and Wang, 1970], in which event a single regression curve would describe the NYU counting rates versus Inuvik. More recent observations [Kane and Winckler, 1969;Stoker and Carmichael;Jenkins et al, 1971;Schmidt, 1972;Stoker et al, 1972] confirm our conclusion that a deviation from the single regression line can and indeed has occurred. From the regression curves for the different periods, shown in Figure 5, we can deduce that the neutron flux at the high-latitude transition maximum can vary by as much as 5-10% at the same neutron monitor counting rate.…”

“…Seven several measurements of the fast neutron spec-pulse height channels were recorded in the trum in the upper atmosphere [Haymes, 1964; flight instrument, each channel corresponding Albernhe and Talon, 1969; Bhatt and Parikh, to a difference of HI Mev in proton recoil 1970; Lockwood et al, 1970;Zobel et al, 1972] energy. The principal response of the spectromand above the atmosphere [Baird and Wilson, cter was in the 1-to 10-Mev range of neutron 1966; Jenkins et al, 1971] at different solar energy, but t]•ere was a finite contribution, to epochs and at different geomagnetic locations. the detector counting rates from proton recoils To discuss the work of these and other in-and nuclear stars produced in the inner scintilvestigators in terms of our observations, we lator by neutrons •10 Mev.…”

Pre-engineering spaceflight validation of environmental models and the 2005 HZETRN simulation code

“…The leakage flux was measured on the OGO-6 satellite by the University of New Hampshire (Lockwood 1972) during June 1969. The leakage flux spectrum was measured (Jenkins et al 1971, Preszler et al 1972) and calculated (Korff et al 1979) by various groups over Palestine, Texas during September 1971 and approximated by Wilson et al (1999) as…”

Ames Collaborative Study of Cosmic Ray Neutrons

“…Cosmogenic radionuclide production: The cosmogenically produced radionuclides such as 3 H, 7 Be, ' 4 C, 2 2 Na, and 4 * Ar result from the interactions of cosmic rays with the atmosphere. An improved understanding of cosmic-ray interactions will therefore improve our understanding of the production of these radionuclides.…”