MONISE BRITO GOMES
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Artigo IPEN-doc 30353 Study of the centers responsible for the TL emission by EPR and PL analysis of Eu-doped CaSiO3 phosphors synthesized by the devitrification method2024 - GONZALES-LORENZO, CARLOS D.; GUNDU RAO, T.K.; CCOLLQUE-QUISPE, ALBERTO A.; AYALA-ARENAS, JORGE; GOMES, MONISE B.; SILVA-CARRERA, BETZABEL N.; GENNARI, ROSELI F.; PACHAS, VALERIA S.; MONZON-MACEDO, F.; LORO, H.; CHUBACI, JOSE F.D.; CANO, NILO F.; ROCCA, RENE R.; WATANABE, SHIGUEOCaSiO3 doped at different ppm of Eu were synthesized by the devitrification method. Polycrystals exhibit a prominent high-temperature TL peak that increases in intensity and shifts toward higher temperatures with increasing amounts of dopant. TL emission spectrum of CaSiO3: Eu displays two very broad bands centered at 400 and 440 nm corresponding to the temperatures of 229.5 and 373.5 degrees C, respectively. PL measurements indicate the presence of Eu2+ and Eu3+ ions. EPR spectrum arises from two defect centers. One of the centers with principal g-values 2.016, 2.0091, and 2.0051 is attributed to O- ion and the center correlates with the TL peak at 236 degrees C. Center II with an isotropic g-value of 2.0018 is attributed to an F+ center and the center relates to the TL peak at 120 degrees C. Center III is also tentatively identified as the F+ center which is associated with the TL peak at 365 degrees C.Artigo IPEN-doc 29622 Luminescence dating and firing temperature determination of ancient ceramics fragments from the Tunata-hill site in the Churajon archaeological complex in Arequipa, Peru2023 - PACOMPIA, YOLANDA; SUPO-RAMOS, JUSTO G.; GONZALES-LORENZO, CARLOS D.; CALLO-ESCOBAR, DARWIN J.; ROCCA, RENE R.; PASTRANA, ELIZABETH C.; GOMES, MONISE B.; SILVA-CARRERA, BETZABEL N.; WATANABE, S.; AYCA-GALLEGOS, OSCAR; AYALA-ARENAS, JORGE S.Ancient pottery fragments from the Tunata-hill site in Churajon archaeological complex, Arequipa, Peru, were dated by means of luminescence techniques such as thermoluminescence (TL) and optically stimulated luminescence (OSL) in order to provide absolute chronology. For TL, additive and regenerative methods were performed. For OSL a regenerative method was carried out for IRSL dating. A rigorous description of the study area and its context has been made. The ages of the samples were found to be between 0.50 ± 0.06 ky and 0.49 ± 0.03 ky for TL methods, and 0.49 ± 0.02 ky for OSL methods. On average, the estimated age by TL and OSL techniques is 490 ± 70 yr (1600 AD and 1460 AD). This means that Churajon ceramics under study would belong to the Late periods which corresponds to the Inca region, and the North sub-region of the Late Churajon phase, and the beginning of European colonization in Peru. X-ray fluorescence technique (XRF) analysis has shown the main presence of Fe (39.5%), Si (30.0%), and Al (10.4%) in fine pottery powder. Furthermore, the electron paramagnetic resonance (EPR) technique was used to study the firing temperature using the iron signal (Fe3+) as a firing temperature reference. The firing temperature of ceramics was found to be around 550 ± 50 °C.