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The radiation fields on board aircraft are quite complex and cover an energy range that is unusual in ordinary radiation protection work. Usually dosemeters measure only one radiation quality and the mixture found on board makes measurements complicated. There is also some doubt when it comes to the best choice of quantity for this application and no radiation standards exist for this kind of radiation field. For those reasons there is a need to find a standard measurement procedure that could serve as a reference for other, maybe simpler, measurements or for calculations of route doses. The only direct reading dosemeter that both measures the absorbed dose to tissue and the radiation quality (in terms of lineal energy) is the tissue-equivalent proportional counter (TEPC). The instrument was originally developed for scientific purposes and is still used as such. The detector consists of a gas filled cavity surrounded by a few mm thick wall. Both wall and gas consists of tissue-like material. The measurement principles are explained. Results observed with TEPC instruments are demonstrated. A preliminary collection of data reported by different groups from measurements on board aircraft will be shown. The results agree within +/- 20%. The conclusion is that TEPC instruments have the capacity of serving as reference instruments.

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The aim of the study reported in this paper was to derive factors describing the translocation of radiocesium from the green plant parts to the crop. Wheat, rye and potatoes were contaminated and harvested at different growth stages to allow the assessment of the contamination of the crop with known date of the radioactive deposition. At harvest, the cesium concentrations in the crop, the green plant parts (i.e., straw without ears) and the roots were measured. The results show that the contamination of the crop depends strongly on the date of ~34Cs application and on the type of plants. The highest translocation was observed when cesium was applied during flowering.