LUCAS SATIRO DO CARMO
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Artigo IPEN-doc 26301 Dating aeolian sediments from Cabo Frio, Rio de Janeiro, using Ti-Li center electron spin resonance, thermoluminescence and optically stimulated luminescence2019 - CARMO, LUCAS S. do; WATANABE, SHIGUEO; DEWITT, REGINA; SILVA, RAFAELA J.; FELIPE, LUIZ; CHUBACI, JOSÉ F.D.In this work, optically stimulated luminescence (OSL), thermoluminescence (TL) and electron spin resonance (ESR) were used to date coastal aeolian sediments from a dunefield known as Dama Branca (White Lady) in Rio de Janeiro, Brazil. Sediments have been collected from seven different points to study sand transportation and stabilization. Results obtained by those different techniques were compared. The equivalent dose (De) measured by OSL, was obtained using the Single Aliquot Regenerative protocol (SAR), TL results have been corrected measuring residual TL and ESR measurements were carried out using Ti-Li center. The thermal stability of Ti-Li center was evaluated, samples were preheated to exclude the Ti-Li center thermally sensitive component. The gamma-ray spectroscopy was used to measure Uranium, Thorium and Potassium concentrations in the soil, the values were analyzed with the Dose Rate and Age Calculator (DRAC) to generate the Annual Dose Rate (Dr). A morphological analysis showed that the dunefield has been moving influenced by semi-arid conditions and upwelling close to the coast. Ages from 0.05 to 2.22 thousand of years were found.Artigo IPEN-doc 23514 Dating stalagmite from Caverna do Diabo (Devil´S Cave) by TL and EPR techniques2016 - WATANABE, SHIGUEO; CANO, NILO F.; RAO, T.K.G.; SILVA-CARRERA, BETZABEL N.; CARMO, LUCAS S.; QUINA, ANTONIO J. A. DE; GENNARI, ROSELI F.; MUNITA, CASIMIRO S.; AYALA-ARENAS, JORGE S.; FERNANDES, BRUNO G.A cylindrical fragment of stalagmite from Caverna do Diabo, State of São Paulo, Brazil, has been studied and dated by thermoluminescence and electron paramagnetic resonance techniques. The thermoluminescence glow curves of stalagmite samples and subsequently gamma irradiated, have shown rise of three peaks at 135, 180 and 265 °C. From electron paramagnetic resonance spectra of stalagmite was possible to clearly identify three paramagnetic centers in the g = 2.0 region: Centers I, II and III are due to , and , respectively. The additive method was applied to calculate the accumulated dose using thermoluminescence peak at 265 °C and the electron paramagnetic resonance signal at g = 1.9973 of CO- 2 radical. The ages of the different slices of stalagmite were determined from the Dac- values and Dan- value, obtaining an average of 86410 for central slice, 53421 for second slice, 31490 for third slice and 46390 years B.P. for the central region of upper end.