Contribuciones a la mejora de la determinación de radionucleidos mediante espectrometría de radiación gamma

Resumo

The determination of gamma emitting radionuclides in different types of matrices and scenarios is carried out through the application of the gamma-ray spectrometry technique. The use of this analytical technique requires the measurement of samples with different geometries, densities and elemental chemical compositions. There are also very different radionuclides to be detected, covering a wide energy range in the emission spectra. Efficiency calibration is very important for the reliable and traceable estimation of activity by gamma-ray spectrometry. The diversity in measurement geometries, densities and elemental chemical compositions found in the majority of the cases, implies that the use of experimental standards with the same characteristics of the measured sample is, in practice, impossible. In “in situ” measurements, experimental efficiency calibration is rather a long and tedious process requiring the use of several certified point sources. Due to these inconveniences, during last years the use of Monte Carlo simulation to this task has gained popularity. The main objective of the thesis is the improvement of the determination of radionuclides by gamma-ray spectrometry using Monte Carlo simulations. The improvements and contributions will be carried out through the study of different factors associated to efficiency calibrations in diverse types of matrices and “in situ” applications. The international scientific community dedicated to the detection by gamma-ray spectrometry has required these aforementioned tasks and improvements.