14th International Conference on Nuclear Microprobe Technology and Applications

Implementation of ionoluminescence in the IBA micromapping setup of AGLAE facility

11 Jul 2014, 11:50

20m

Auditorium (Centro Culturale San Gaetano, Padova)

Oral Communication Session 11 - Nuclear Microprobe Applications: Art and Archaeometry

Speaker

Mr Laurent PICHON (Centre de recherche et de restauration des musées de France - C2RMF, Palais du Louvre, Paris, France)

Description

Ion beam induced luminescence (IBIL) is a powerful technique that provides information beyond those obtained by IBA methods. For instance, it can be used for the detection of rare earth elements, differentiation of mineral polymorphs and visualization of crystalline defects. The coupling of IBA and IBIL is very promising for the study of complex targets such as Cultural Heritage artefacts. Moreover, the characterization of these often heterogeneous samples requires imaging at various scales. A new IBIL imaging system has been fully integrated to the external microbeam line of the AGLAE facility. The IBA microimaging system where the IBIL setup has been implemented exhibits specific features. Fast elemental mapping of large areas (mm to cm) is obtained by combining a vertical magnetic deflection of the beam with a horizontal mechanical translation of the target and data are acquired in list mode. Both specifications are hardly compatible with the collection of an IBIL spectrum. This work details the IBIL setup, gives its performances and explains the technical solutions retained to couple IBIL with IBA in order to produce fast and large IBIL-IBA maps. The luminescence signal is collected through a 1mm diameter fiber without focusing optics to an Ocean Optics QE65000 spectrometer. It records spectra from 200 to 1000 nm with a minimum collection time of 8ms thanks to an USB 2.0 port. The frequency of the magnetic vertical deflection has been adjusted so that dwell time on each position allows a proper IBIL acquisition without notably slowing down IBA mapping. Imaging of a 1-cm² area with a 40-µm resolution can last less than one hour. The IBIL acquisition is made through specially developed software which, for every position, saves the spectrum, creating a data cube file. Then IBIL information can be mapped in 2D and visualized with the AGLAEmap program which also permits data extraction from coupled IBA-IBIL maps. Examples of coupled mapping on Cultural Heritage materials will be presented to emphasise the interest of performing simultaneously IBA and IBIL large mappings.