f Comparison measurements of terrestrial radiation by geophysical instruments

Regional and detailed measurements of terrestrial radiation are carried out by airborne and ground geophysical methods. Radiometric data and maps are affected by specific features of radiometric measurement, namely by the statistical character of radioactive decay, detectors and technical parameters of instruments, calibration standards and instrument calibration procedures, sampling time, geometry of field measurements and by the data processing. If the radiometric data are used for the quantitative assessment of the natural radiation environment and radioactivity of anthropogenic objects, building materials and nuclear fall-out, reliability of radiometric data must be acceptable and verified. Coincidence and deviations of radiometric data has been tested by a series of comparison measurements of various instruments.