Frequency of heavy ions in space and their biologically important characteristics

A review of the galactic cosmic ray energy spectra of heavy ions with Z< or = 28 is presented. Fluxes of these ions within critical body organs of astronauts travelling outside the magnetosphere will be modified from the free space values by fragmentation within the spacecraft and the bodies of the astronauts themselves. The effects of such fragmentation are presented in terms of variations in the particle flux above a given dE/dx at representative depths. Present limitations to the accuracy of such calculations are considered. The validity of dE/dx as a relevant physical parameter for characterizing the biologically important component of the heavy ion radiation environment is discussed.