The Atmospheric Background Of Protons And Deuterons Measured At 5 G/Cm(2).

The SMILI-2 balloon-borne instrument measured the low energy (30-200 MeV/nucleon) proton and deuteron fluxes at an atmospheric depth of 5 g/cm(2) in 1991, a period of high solar activity. As secondary protons and deuterons make a significant contribution to the measured fluxes at low energy, the SMILI data can be used to constrain model calculations for the secondary fluxes. We describe the secondary production calculations and compare our results to previous atmospheric background calculations in the literature.