Cosmic rays and dosimetry at aviation altitudes

Recent concerns regarding the effects of the cosmic radiation field at airc raft altitudes on aircrew have resulted in a renewed interest in detailed m easurements of the neutral and charged particle components in the atmospher e. CR-39 nuclear track detectors have been employed on a number of subsonic and supersonic aircraft to measure charge spectra and LET spectra at aircr aft altitudes. These detectors are ideal for long term exposures required f or these studies and their passive nature makes them suitable for an enviro nment where interference with flight instrumentation could be a problem. We report here on measurements and analysis of short range tracks which were produced by high LET particles generated mainly by neutron interactions at aviation altitudes. In order to test the overall validity of the technique measurements were also carried out at the CERN-CEC field which simulates th e radiation field at aviation altitudes and good agreement was found with d ose values obtained using mainly heavy ion calibration.