DOSIMETRY FOR OCCUPATIONAL EXPOSURE TO COSMIC-RADIATION

In the course of their work, aircraft crew and frequent flyers are exp osed to elevated levels of cosmic radiation of galactic and solar orig in and secondary radiation produced in the atmosphere, aircraft struct ure, etc. This has been recognised for some time and estimates of the exposure of aircraft crew have been made previously and included in, f or example, UNSCEAR (United Nations Scientific Committee on the Effect s of Atomic Radiation) publications. The recent increased interest has been brought about by several factors - the consideration that the re lative biological effectiveness of the neutron component was being und erestimated; the trend towards higher cruising altitudes for subsonic commercial aircraft and business jet aircraft; and, most importantly, the recommendations of the International Commission on Radiological Pr otection (ICRP) in Publication 60, and the revision of the Euratom Bas ic Safety Standards Directive (BSS). In 1992, the European Dosimetry G roup (EURADOS) established a Working Group to consider the exposure to cosmic radiation of aircraft crew, and the scientific and technical p roblems associated with radiation protection dosimetry for this occupa tional group. The Working Group was composed of fifteen scientists (pl us a corresponding member) involved in this field of study and with kn owledge of radiation measurement at aviation altitudes. This paper is based on the findings of this Working Group. Where arrangements are ma de to take account of the exposure of aircraft crew to cosmic radiatio n, dose estimation procedures will not be necessary for persons for wh om total annual doses are not liable to exceed 1 mSv, and therefore, i n general, for crew on aircraft not routinely Eying above 8 km. Where estimates of effective dose and, in the case of female staff who are p regnant, equivalent dose to the embryo or fetus, are required (for reg ulatory or other purposes), it was concluded that the preferred proced ure was to determine route doses and fold these with data on staff ros tering.