The Laboratory of Non-Destructive Optical Spectroscopy – LEOnoD and its first results with p-XRF and LIBS
Luízar Obregón1, M.A. Zamalloa Jara2, K. Contreras3
1 Departamento Académico de Química – Facultad de Ciencias-Universidad Nacional de San Antonio Abad del Cusco. Av. de la Cultura 733. Pab LQ-201. Cusco. Perú. E-mail: firstname.lastname@example.org, Tel/fax: 0051-84-224831
2 Departamento Académico de Física – Facultad de Ciencias-Universidad Nacional de San Antonio Abad del Cusco. Av. de la Cultura 733. Pab C-361. Cusco. Perú. E-mail: email@example.com, Tel/fax: 0051-84-224831
3 Asociación Civil Francesa “Puya de Raimondi”, 3 Boulevard de la Vanne, Cachan, Francia. E-mail: firstname.lastname@example.org
In order to begin the study of the material cultural heritage of Peru, the implementation of Optical Non-Destructive Spectroscopy Laboratory Techniques (LEOnoD) and the Study of PIgments in inca CEramic using Laser-induced optical breakdown spectroscopy – EPICENTRO were financed in 2016. It was purchased a handheld X-ray fluorescence spectrometer (Olympus) and a laser-induced ablation spectrometer (APPLIED PHOTONICS).
The three more important studies conducted with pXRF were: “Exploratory analysis for the identification of false banknotes using portable X-ray Fluorescence spectrometer”, published in Applied Radiation and Isotopes. Secondly “Elemental analysis of pigments in the ceramic huacothroat-cutter warrior with trophy using x-ray fluorescence spectroscopy”, that researched the authenticity of the piece, it was submitted in October 2017 to Journal of the Chilean Chemical Society; and third the study of the print illuminated “La Gloria” from La Recoleta temple in Cusco, in the 18th century, as part of the Bachelor thesis on Restoration degree.
With LIBS, we started some preliminary experiments in ceramic materials. Due to the complexity of the spectra and the laborious recognition of the spectral lines of the elements, a correlation algorithm was developed between the spectra obtained at the same point at different depths. This allowed the identification of the difference in elementary composition.
Finally, in 2018 we obtained financing for the study of pigments in documents of the Historical Archive of Cusco. The preliminary analysis of the document “Tupac Amaru-II family tree” (18th century) indicate the use of gold, copper and iron among others.
Keywords: optical spectroscopy, pigment composition, cultural heritage, elemental analysis