Overview and present status of the European Commission research programme

By the early 1990s the European Commission agreed that a comprehensive survey of the radiation environment produced by cosmic rays at aviation altitudes should be undertaken and that an extensive programme of experimental and theoretical studies should be supported. By calling on the resources of scientists in the fields of neutron physics, cosmic ray physics and general dosimetry it was felt that a successful investigation could be undertaken using the techniques and expertise of all concerned. By employing a wide range of detectors on several routes, both on subsonic and supersonic aircraft, a detailed set of measurements was obtained over a five- year period. Many of the measurements were made simultaneously by several instruments on the same flights so that intercomparison of results was possible. Detectors were also deployed on high altitude mountains to facilitate extrapolation of data to lower altitudes for verification of theoretical models. Instruments were calibrated in the CERN-CEC reference field and at other accelerator centres. While experiments and analysis continue, quantities relevant to radiation protection of aircrew and passengers are being investigated. (13 refs).