Combined THz and LIPS analysis of corroded archaeological bronzes

In this work we have studied corroded archaeological artefacts by combining THz and laser induced plasma spectroscopy (LIPS). The main aim of the work was the assessment of the potential of the THz TDS reflectometry for achieving stratigraphic information and the presence of the metal bulk beneath encrustations and alteration layers before measuring LIPS elemental depth profiles. The behaviour of the reflected THz pulses was formerly investigated by preparing a set of suitable mock-ups, then measurements were carried out on a set of authentic archaeological samples exhibiting different stratigraphic situations, and eventually a deeply corroded Egyptian bronze figurine was characterised. The results achieved show the range of stratigraphic information, which can be provided by THz and the advantages of the present analytical combination.