C. Calza

Characterization of Brazilian artists’ palette from the XIX century using EDXRF portable system

In this work were characterized the palettes of some of the most representative Brazilian painters from the XIX century: Eliseu Visconti, Almeida Junior, Rodolfo Amoedo, Henrique Bernardelli, Rafael Frederico, Modesto Brocos, Augusto Rodrigues Duarte and Pedro Peres. EDXRF measurements were carried out with a portable system consisting of an X-ray tube Oxford TF3005 and a Si-PIN XR-100CR detector from Amptek. Some pigments identified were: zinc and lead white, ochre, umber, vermilion, Prussian blue, cobalt blue, cadmium yellow, black iron oxide, etc.

Analysis of a Brazilian baroque sculpture using Raman spectroscopy and FT-IR

In this study, samples were taken from the sculpture of Our Lady of Sorrows and analyzed by Raman spectroscopy and FT-IR. This sculpture has been dated to the early eighteenth century. Samples were also examined using optical microscopy and Energy Dispersive Spectroscopy (EDS). Based on chemical analysis, the pigments vermilion [HgS], massicot [PbO] and azurite [Cu3(CO3)2(OH)2]were found in the sculpture polychrome. The results indicate that the green polychrome of the sculptures mantle comes from the blending of massicot and azurite. Because the literature reports that the mantle of the Our Lady of Sorrows sculpture is blue, the mixing of these pigments results from a production error. The results also indicate the presence of Au in the sculpture, which indicates the originality of the piece. The results from this study helped restorers to choose the appropriate procedures for intervening in the sculpture and contributed to the knowledge about the manufacturing process of Brazilian baroque sculptures.

Biological tissues analysis by XRF microtomography

The main of this work is to determine the elemental distribution in breast and prostate tissue samples in order to verify the concentration of some elements correlated with characteristics and pathology of each tissue observed by the X-ray transmission microtomography (microCT). The experiments were performed at the X-ray fluorescence beamline of the Brazilian Synchrotron Light Laboratory. The microCT images were reconstructed using a filtered-back-projection algorithm and the XRF microtomographies were reconstructed using a filtered-back-projection algorithm with absorption corrections.

Imaging System for XRF Microtomography at LNLS-Brazil

An X-ray transmission microtomography (CT) system combined with an X-ray fluorescence microtomography (XRFCT) system was implemented in the Brazilian Synchrotron Light Laboratory (LNLS), Campinas, Brazil. The main of this work is to determine the elemental distribution map in reference samples and breast tissue samples in order to verify the concentration of some elements correlated with characteristics and pathology of each tissue observed by the transmission CT. The experiments were performed at the X-Ray Fluorescence beamline (D09B-XRF) of the Brazilian Synchrotron Light Laboratory, Campinas, Brazil. A quasi-monochromatic beam produced by a multilayer monochromator was used as an incident beam. The sample was placed on a high precision goniometer and translation stages that allow rotating as well as translating it perpendicularly to the beam. The fluorescence photons were collected with an energy dispersive HPGe detector placed at 90deg to the incident beam, while transmitted photons were detected with a fast Na(Tl) scintillation counter placed behind the sample on the beam direction. The CT images were reconstructed using a filtered-back projection algorithm and the XRFCT were reconstructed using a filtered-back projection algorithm with absorption corrections.

Analysis of clay smoking pipes from archeological sites in the region of the Guanabara Bay (Rio de Janeiro, Brazil) by FT-IR.

In this study, twenty samples of clay smoking pipes excavated in an 18km(2) area between the Macacu and Caceribu rivers, in the municipality of Itaboraí, Rio de Janeiro, Brazil were analyzed by FT-IR technique. The samples, excavated in different archeological sites of the region, are dated between the seventeenth and the nineteenth centuries and are part of the material culture left by Africans and African descendants that lived in the complex. FT-IR analyses and complementary SEM-EDS studies showed that the clay paste used in the manufacture of smoking pipes, mostly handcrafted, is composed of quartz, feldspar, phyllosilicates and iron oxides. Multivariate statistical tests (PCA) were applied to FT-IR data to assess the interactions between the archeological sites. The results indicated that one archeological site - Macacu IV - is greatly related to the other sites. The results obtained have helped archeologists and anthropologists in better understanding the manufacturing process employed in ancient ceramic artifacts produced during the period of colonial Brazil.

Análise de peroleiras e cachimbos cerâmicos provenientes de escavações arqueológicas

This article presents the results of the analysis of olive jars and ceramic pipes fragments, from archaeological excavations performed in the region located between the rivers Macacu and Caceribu, in the state of Rio de Janeiro, using the techniques of X-ray Fluorescence (XRF), Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEM-EDS) and multivariate statistics. Some olive jars from the shipwreck of the Galleon Santissimo Sacramento, which occurred in the coastal of Bahia in 1688, were also analyzed and the results compared with those obtained for the fragments found in Rio de Janeiro. In this context, is proposed a methodology of analysis for ceramic artifacts which can assist not only in its characterization, as also provide support for constructing interpretations concerning the production and use of these objects.