Study of the capabilities of a detector based on a lanthanium bromide crystal for assessing 137Cs activity concentration in deep soil layers
Year: 2025
Type: article
Abstract: During expeditionary radiation-hygienic studies of territories, there is often a need to assess activity concentration of radionuclides in soil at depths greater than 20 cm. This is associated with certain methodological and technical difficulties in sampling. The aim of this study was to carry out a series of calibration measurements and evaluate the capabilities of a collimated scintillation detector for determining 137Cs activity concentration in soil at different depths in boreholes in situ. Materials and Methods: A comprehensive calibration was carried out for the MKSP-01 RADEK gamma spectrometer with a LaBr3(Ce) crystal, including a study of the axial sensitivity and detection efficiency for the 137Cs radionuclide from both a point source and a volumetric soil source with known activity. This made it possible to determine the optimal measurement parameters, including the distances between collimators and calibration coefficients for accurate determination of activity concentration at different distances and with different sample volumes. Results and Discussion: This article presents the results of calibration of the detector based on a LaBr₃(Ce) crystal measuring ∅30х30 mm, designed to measure the intensity of 137Cs gamma radiation in boreholes at depths of up to 1 m. The calibration measurements showed that the detector design allows measuring activity concentration of 137Cs from 200 Bq/kg in boreholes with a diameter of 90 mm, with the 137Cs peak detection efficiency of about 0.1% and a measurement time of 30 min. The detector ensures reliable detection of soil layers with 137Cs activity above the minimum significant activity concentration. Conclusion: Collimators providing access of gamma radiation to the open part of the LaBr3(Ce) crystal allow adjusting the thickness of the studied soil layer (horizon view width) during the measurement process. With a distance between the collimators of 1.5 cm, the detector allows studying the activity concentration horizons with a step of 5 cm, with an increase in the distance to 2 cm – 10 cm.
Source: Radiacionnaâ gigiena
Authors: K. А. Razin, K. V. Varfolomeeva, K. A. Sednev, V. S. Repin, S. A. Zelentsova
Language: English
Subfield: Radiation
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: diamond
OpenAlex ID: W4415017016