Exposure of aircrew to cosmic radiation. Calculation and experimental approach

摘要

Exposure to cosmic radiation increases rapidly with the altitude. At the flight levels of commercial aircraft, it is of the order of several μSv per hour. Most aircrews are exposed regularly to the effective dose exceeding 1 mSv/year, the limit of exposure for nonprofessionals defined in the International Commission on Radiological Protection (ICRP) 60 recommendations, which were already incorporated to the Czech regulation since 1997. That is why this problem has been intensively studied in the author's laboratory since the beginning, and the contribution reviews this effort. First, some experimental studies have been realised in 1991-1994. Later, a preliminary analysis of the exposure of the aircrew of companies operating in the Czech Republic has been realised based on the calculation by means of the transport code CARI (Civil Aeromedical Research Institute). Afterwards, the procedure of aircrew exposure estimation has been elaborated. The procedure was proposed to the Czech authorities to be used for all Czech companies concerned. It has been finally accepted, and the results concerning the exposure of aircrew during 1998 and 1999 are presented, analysed, and discussed. New experimental studies also followed. Mostly, active dosimeters were used to estimate low and high linear energy transfer component of the radiation field on board. The measurements on-board have been performed since 1999 in about 10 commercial flights. The results obtained were transformed to the effective dose and compared with the values of the same quantity calculated by means of the CARI. A reasonable agreement of both sets of data could be stated.