Numerical simulations with the MCNPX and LAHET Code Systems compared with direct measurement of neutron fluxes in terrestrial environments

摘要

Neutron fluxes as a function of geomagnetic latitude were investigated using both the MCNPX and LAHET Code Systems (LCS) and compared with Southern Hemisphere measurements made during 1998-2001. Preliminary calculations for neutron fluxes near sea level at various geomagnetic latitudes are consistent with the measured values using a cosmic-ray flux slightly lower than the effective proton flux associated with nuclide production in lunar samples over thousands to millions of years. This lower neutron flux could be due to the strong solar modulation effect during the measurement period.