Measured and Calculated Neutron Spectra and Dose Equivalent Rates at High Altitudes; Relevance to SST Operations and Space Research

摘要: Results of the NASA Langley-New York University high-altitude radiation study are presented. Measurements absorbed dose rate and secondary fast neutrons (1 to 10 MeV energy) during years 1965 1971 used determine maximum exposure from galactic solar cosmic rays supersonic transport (SST) subsonic jet occupants. The equivalent rates that SST crews might receive turn out be 13 20 percent permissible (MPD) for workers (5 rem/yr). passengers encountering an intense giant-energy particle event could exceed MPD general population (0.5 rem/yr), but would within these limits if in such rare cases descends altitude; it is less than 12 MPD. By Monte Carlo calculations buildup nucleons air incident proton energies E 0.02 GeV, measured neutron spectra were extrapolated lower higher found continue with a relatively high intensity greater 400 MeV, wide altitude range. This condition, together profiles neutrons, revealed biologically important energetic penetrate deep into atmosphere contribute approximately 50 equivalant at present altitudes.