Speaker
Description
LaBr$_3$:Ce (2" x 2") detectors were used to measure soil samples placed in Marinelli beakers in singles and coincidence modes. Time-stamped data were acquired and background removed offline by using photon time-of-flight in addition to measurement of the two photon energies in coincidence. Coincident gamma-ray pairs from $^{238}$U ($^{214}$Bi) and $^{232}$Th ($^{208}$Tl) series were identified in measured samples. The activity concentrations of $^{238}$U and $^{232}$Th series radionuclides inside the samples were determined in both singles and coincidence modes. The internal activity of the LaBr$_3$:Ce detector increases the MDA at 1460.8 keV and 2614.5 keV, which limits the measurement of $^{40}$K radionuclide with low activity concentration in singles mode. The measured internal activity of $^{138}$La in the LaBr$_3$:Ce detector crystal is 263.8 $\pm$ 26.8 Bq kg$^{-1}$ which is comparable to the calculated activity of 293.3 Bq kg$^{-1}$. The suitability of the use of these detectors for NORM measurements was evaluated.
