Experimental approach to the exposure of aircrew to cosmic radiation

Results of measurements made on board subsonic aircraft since 1991 are presented and discussed. Several types of active devices as well as passive detectors have been used. The same types of instruments have also been tested in high energy reference fields at CERN and at JINR Dubna. This has permitted the correction of the readings of neutron dosemeters for the probable spectrum on board. The correction factor for low LET radiation measuring instruments has been estimated on the basis of available particles (electrons, protons) spectra. It has been found that the exposure level depends on parameters known from theoretical considerations (geomagnetic position, flight altitude, etc.), some concrete examples are given. The measured data have also been compared with the data available from the world network of cosmic radiation monitors. It has been found that the correlation is satisfactory. Nevertheless, the studies have to continue until after the next solar minimum (similar to 2007) to improve the reliability of the correlation. Some comments on radiation protection aspects of the topic are also made.