Radiation Protection in Aviation

Kurzfassung

The lecture gives an overview of the complex interdisciplinary area of radiation protection in aviation, which comprises biomedical, legislative, physical and practical aspects. The radiation exposure at aviation altitudes is the result of cosmic rays generated by interactions of primary high-energy particles of cosmic origin with atoms in upper layers of the Earth’s atmosphere. The intensity of the corresponding radiation field, which aircrew and passengers are exposed to, depends on barometric altitude, geomagnetic latitude, and solar activity. The influence of solar activity, i.e., Space Weather (SWx), varies within an approximately 11-year cycle, the minimum of which corresponds to the highest radiation levels at aviation altitudes. This effect is a result of the reduced shielding of the galactic cosmic radiation (GCR) by the interplanetary magnetic field (IMF), which is modulated by the solar wind, i.e., the solar activity. Furthermore, rare solar particle events (SPEs), which are sometimes referred to as solar flares in aviator’s jargon, can temporarily generate significant changes, i.e., increases or decreases, in the corresponding dose rates at aviation altitudes. Dose monitoring and recording of the radiation exposure of crew members have been obligatory in the European Union (EU) since legislation based on the EU Directive 96/29/EURATOM became effective. The corresponding EU directive stipulates basic standards for the radiation protection of aircrews that are regarded as radiation workers due to their exposure to cosmic rays. The effects of SPEs on the radiation field at aviation altitudes are demonstrated with a case study of two Ground Level Enhancements (GLE 65 & GLE 66), which took place during the Halloween solar storms. The lessons learnt from these events led to the development of the Space Weather D-Index for aviation.