TriENA: a Portable, Hybrid Multimode Spectrometer Combining Diffuse Reflectance, LED-Induced Fluorescence, and Laser-Induced Breakdown Spectroscopy for a Holistic Analysis of Materials on Monuments and Objects of Archaeological Interest.

In the context of modern Heritage Science (HS) studies, chemical analysis together with contextual information provide valuable insights into the composition and structure, provenance, age, and/or production technology of objects and materials, facilitating also decision-making concerning the selection of appropriate conservation approaches for artifacts and monuments. While powerful laboratory techniques are often employed in such investigations, an increasing demand exists for the use of portable instrumentation that can be deployed at archaeological sites or museums. To address these needs, TriENA, a portable, hybrid instrument, has been developed, which integrates three complementary spectrochemical tools: Laser-Induced Breakdown Spectroscopy (LIBS), LED-Induced Fluorescence (LED-IF), and Diffuse Reflectance (DR) spectroscopy. These techniques facilitate compositional analysis of different types of materials, including metals, alloys and their corrosion products, pottery, pigments in various types of painted objects, or the identification of biodeterioration on stone monuments. In this article, the design concept of TriENA is presented. Detailed technical information concerning the main components of the instrument is provided, and key engineering aspects are discussed. A series of test cases demonstrate that this hybrid spectrometer is a valuable and versatile tool for conservators, heritage scientists, and archaeologists, as it enables rapid, portable, and comprehensive characterization of a wide range of objects, addressing a broad spectrum of analytical challenges.