Optimizing calibration factors of plastic scintillation fibers for improved accuracy of radiocesium concentration measurements in bottom sediments of agricultural ponds

Katengeza, E. W.*; Sanada, Yukihisa   ; Ochi, Kotaro   ; Iimoto, Takeshi*

The uncertainty of radioactivity measurements can be influenced by the vertical distribution of the target radionuclide in the sediments. This study used 2015-2019 field measurement data from 47 ponds to evaluate the depth dependence of calibration factors of plastic scintillation fiber (PSF) and its influence on measurement uncertainty. By changing the depth of focus from 10 cm to 15-20 cm when calculating the conversion factor, the normalized mean square error of the radiocesium concentration estimated by the PSF with respect to the radiocesium concentration in core sediments sampled at the same location was found to be smaller.