System S.E.M.\E.D.S.

Microanalysis is based on the collection of X-rays emitted by atoms of the sample after bombardment by the electron beamand following desexcitation. The analysis is based on their energy, making possible the identification of:

• Chemical elements in a sample (qualitative analysis)
• Their quantification (quantitative analysis)
• Their distribution in the sample (mapping)
• The Spectrometer Energy dispersive X-ray that exists in the Laboratory is the ISIS Link 300, one of the most sophisticated of its kind. It features Si (Li) high resolution detector that allows fast qualitative and quantitative microanalysis of elements with atomic number greater than beryllium (Be). Accompanied by the corresponding software that aims to:
• Qualitative and quantitative analysis polished thin sections
• Qualitative and quantitative analysis of untreated samples
• Qualitative and quantitative analysis of biological samples
• Fast digital mapping of the sample
• Linear scan (speed map)
• Image processing
• Analysis of morphological and chemical characteristics of the sample

System T.E.M.

Transmission Electron Microscopy analysis conducted on a JEOL, JEM-2100 high-resolution system (HR-TEM) with point and lattice resolution equal to 0.23nm and 0.14nm, respectively. It operates at accelerating voltage of 80, 100, 120, 160 and 200 kV. Precession Electron Diffraction (PED) technique is carried out on a connected SpinningstarP020 (NanoMEGAS) precession unit and special sample holder enables a tilting range of the specimen from -60^o to+60^o along the goniometer x-axis. Images and diffraction patterns are recorded by means of an Erlangshen CCD Camera (Gatan Model 782 ES500W), while films (Kodak SO-163) are used for HRTEM images.  

System X.R.F.

The laboratory is equipped with a complete system of elemental analyzers Wavelength Dispersive X-Ray Fluorescence Spectrometer-WDXRF and Energy Dispersion (Energy Dispersive Element – EDXRF.

XRF spectroscopy is widely used for qualitative and quantitative elemental analysis of a variety of solid and liquid samples. Compared with other techniques, such as Atomic Absorption Spectroscopy and Inductively Coupled Plasma Spectroscopy, XRF technique is advantageous because it is non-destructive, multi elemental, fast and applicable in a wide range of concentrations (100% to few ppm).

XRF is based on the principle that individual atoms, when excited by an external energy source, emit X-ray photons of a characteristic energy or wavelength. By counting the number of photons of each energy emitted from a sample, the elements present may be identified and quantitated.

The X-ray spectrum of a sample subjected to the above procedure a series of characteristic energy peak occurs. The energy position of the peaks leads to the identification of the elements contained in the sample (qualitative analysis), while the intensity arising the relevant or absolute concentrations of sample components (semi-quantitative or quantitative analysis).

Equipment

The Laboratory of Electron Microscopy & Microanalysis includes:

1) The wavelength dispersive X-Ray Fluorescence spectrometer (WD-XRF), ZSX PRIMUS II of RIGAKU, which is suitable for elemental analysis and the determination of all the elements from beryllium (Be) trough uranium (U). The analysis can be performed on samples of solids, liquids, powders, thin films and filters, as well as for determination of trace elements in geological samples and artificial materials, using the Scan Quant X (SQX), SQX Scattering FP and Quant Scattering FP method software, SQX Matching Library.

The ZSX Primus II features a 30 micron (Rh) tube, the thinnest end-window tube available in the industry, for exceptional light element (low-Z) detection limits.

2) The benchtop energy dispersive element X-Ray Fluoresence spectrometer (ED-XRF), NEX CG of RIGAKU.