A dip detector for in situ measuring of Cs-137 specific soil activity profiles

A field method for measurement of Cs-137 contamination depth profiles is described. The method is based on the use of a collimated dip detector created as a gamma-ray probe: CsI(Tl) scintillating crystal + PIN photodiode + front-end electronics. The presented method allows determination of specific activity distribution with vertical spatial resolution of 5 cm. Exposure time for one point in the distribution profile is less than 180 s if the level of specific activity is more than 50 Bq/kg. This method may be applied for efficient and quick inspection of a contaminated river's flood planes in areas with leakage of radioactive wastes. Application of the method for such a task gives an effective solution to obtain qualitative and quantitative characteristics of contamination.