Characterization of geomaterials from NE Portugal using k _0-based instrumental neutron activation analysis (k _0-INAA) and gamma spectrometry methods

摘要

The main objective of this study is the elemental characterization of geomaterial samples ("soils" and Ra?as), collected between 2007 and 2008, in the Morais Massif, (NE Mainland of Portugal) by using two complementary techniques: instrumental neutron activation analysis (INAA) and high resolution gamma spectrometry. Samples granulometric fractions lower than 63 μm were analyzed by gamma spectrometry, for artificial and natural radionuclides using HPGe detectors and by INAA, for chemical elements at the Portuguese research reactor, RPI. Statistical analysis, such as clusters analysis and Pearson correlations were applied to the obtained results. The enrichment factors were also calculated as an estimator of anthropogenic inputs in relation to the average crustal abundance. Group differentiation of Ra?as and "soils" is clearly shown from cluster analysis. The strong correlation factors obtained between some chemical elements corroborates the origins and the geology/mineralogy of the area studied. The combined application of both nuclear analytical techniques has shown their importance in providing useful information for the future site and repository performance and safety assessment studies.