A general methodology to determine natural radionuclides by well-type HPGe detectors

This work aims to determine natural radionuclides (210Pb, 228,226Ra, 234,228Th and 40K) in NORM samples by well-type HPGe detectors because they are of vital importance in studies on environmental samples. For this, a novel methodology has been developed, based on obtaining a general function for the full-energy peak efficiency (FEPE) versus the sample apparent density and composition, keeping the sample height constant. To obtain the general FEPE function, a calibration in efficiency has been accomplished using certified standards provided by IAEA (RGU-1 and RGTh-1), and KCl. Besides, different self-absorption correction functions were compared for cylindrical geometry, where chemical compositions need to be known. Then, a study on using an anti-Compton system was done, getting a lower detection limit and allowing to propose gamma spectrometry as an alternative technique to alpha-particle spectrometry. Finally, the followed methodology to calculate the FEPE was subjected to internal and external validations, checking its validity range.