Individual Dosimetry of Aircraft Crew – Methods and Results in Czech Republic

International Commission on Radiological Protection (ICRP) recommended in its Publication 60 that the radiation exposure due to the cosmic component at high altitudes be taken into account when appropriate as part of occupational exposure to the radiation. The recommendation mentioned was incorporated to the Czech regulation at 1997. The contribution describes first the elaboration of optimal procedure for the aircrew routine individual dosimetry. The procedure was proposed to the Czech authorities and received their accreditation. Routine individual dosimetry has started since 1998. Its results are presented, discussed and analyzed. The experimental studies started in Czech Republic already in 1991. The first campaign was realised in 19911996 years, to assist in the development of routine individual dosimetry method mentioned. The second, during 1999, permitted to verify the validity of it, as well as the third one, realized during 2003 year. Since 2000 year, a Si-semiconductor spectrometer has been also used for onboard aircraft measurements, about 700 commercial Czech Airlines flights were already monitored. The dosemeters were used to estimate low and high linear energy transfer component of the radiation field on board. The results obtained were transformed to the ambient dose equivalent and compared with the values calculated by means of codes CARI and EPCARD. A reasonable agreement of both sets of data could be stated. Basic review of results obtained is presented and discussed from the point of view of individual dosimetry of aircrew. Particular attention is devoted to the results obtained during some extreme situations: an intense solar flare and some “Forbush decreases”.