Thematic area 5


LABORATORY OF SCANNING ELECTRON MICROSCOPY AND ULTRA/HIGH RESOLUTION MICROANALYSIS
Laboratory of ultra-high resolution scanning electron microscopy and ultra/high resolution microanalysis for the morphological, microstructural, texture and chemical characterization of solid materials.
The images acquired through electronic scanning of the sample surface show compositional, structural and morphological inhomogeneities of the material with a lower resolution than a nanometre, both massive or particulate material. In the latter case it characterizes it by shape, size and chemical composition.
The image analysis is completed by the quantitative chemical analysis made possible by a system of X-ray spectrometry (Xrays are excited by the electron beam) in energy dispersion (EDS) and of wavelength dispersive spectroscopy (WDS). It is thus possible to obtain accurate chemical analysis, compositional profiles and chemical maps.
Moreover, by means of the microanalysis in wavelength dispersion it is possible to obtain both detection limits lower than 100 ppm, by including trace elements in the analysis area, and resolutions in the order of 10 eV, necessary to solve interference between spectrometric lines close in energy that otherwise would result overlapping and not attributable to different analytes. Photons-X discriminated by the wavelength dispersion are then collected by a proportional counter that ensures linearity between intensity (numbers of photons) and analyte concentration, essential condition in the quantitative chemical analysis.

Activities
Basic and applied research in the following fields:
• Petrographic and petrological studies: earth sciences, stone materials, cement mortar;
• Planet science: analysis of micro-meteorites and tektites;
• Metallographic studies;
• Composite materials;
• Textile industry: fibre characterization;
• Nanoparticles (graphene...);
• Environmental analysis: asbestos, air particulate filters, heavy metals in soils;
• Cultural heritage: diagnostics, alteration of patina in monuments, study of pigments, characterization of paintings;
• Archaeology: correlative studies on the origin of stone materials;
• Agri-food sector;
• Forensic science: analysis of gunpowder traces and of traces in legal area and investigations;
• Studies of corrosion or passivation phenomena;
• Morphoscopic characterization of porosity;
• Analysis of patinas and varnish;
• Medical sector: characterization of prosthesis;
• Electronics: microlithography (EBL).

Equipment

• Field emission scanning electron microscope model MERLIN ZEISS with following characteristics:
• In-lens detector of secondary electrons;
• In-lens detector of backscattered electrons (eSB: energy selective back scattering): it is possible to filter the energy of the back scattered beam by increasing the compositional contrast even at low voltage;
• Detector secondary in camera;
• Detector of backscattered in camera (aSB: angle selective back scattering): sensitive to the orientation of the crystals in the sample;
• Possibility of immediate and automatic commutation from parallel electron beam (high resolution) to cross beam (analytic mode: high current density) while maintaining the electrooptical beam alignment;
• Microanalysis in energy dispersion (working area 50 mm2) - Model: OXFORD X-MAX;
• Microanalysis in wavelength dispersion – Model: OXFORD INCA WAVE 700 (5 analysing crystals);
• Charge compensation system (Cc: Charge compensator) for observation and microanalysis of non-conductive and/or nonprepared specimen (three dimensional specimen and specimen without coating;
• Module microtest in camera: tensile stage 5kN – Model: GATAN;
• System for preparation: high resolution metal sputter coater and Carbon coater integrated in one system with turbomulecular pump and control of the thickness of the conductive layer – Model: QUORUM TECH: q150t ES.

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