DESCRIPTION OF ACTIVITIES

In the X-ray fluorescence "XRF" laboratory, the chemical analyses of major, minor and trace elements (quantitative and qualitative) are determined on samples of rocks, clays, ceramics, and bricks. The main research activities concern:

- Igneous petrogenesis;

- Archaeometry;

- Research projects conducted within the Department;

- Third party.

LABORATORY EQUIPMENT

Axios Panalytical sequential wavelength dispersion spectrometer (Fig.1), equipped with Rh tube, 6 analyzer crystals (LiF220, LiF200, LiF420, PE002, PX1, TlAP), 3 collimators ((150 μm, 550 μm and 700 μm), 4 filters (Al 200 μm, Al 750 μm, Brass 100 μm, Brass 400 μm) and 2 counters (gas flow counter and scintillator).

Calibration is based on 45 reference standards (K.P. Jochum, J. Enzweiler, 2014, 15.3 - Reference Materials in Geochemical and Environmental Research, Treatise on Geochemistry (Second Edition), Elsevier, Pages 43-70, https://doi.org/10.1016/B978-0-08-095975-7.01403-0). The reference standards are natural geological samples. The software used for the measurements is SuperQ (Fig.2).

Analytical uncertainty is in the order of 1-2% for major elements and 5-10% for trace elements.

 

Routine analysis of a sample

a. Determination of loss on ignition (L.O.I.).

b. Use of the sample powders to prepare the pressed powder pellets.

c. Sample analysis using the Axios Panalytical spectrometer.

 

a. Determination of loss on ignition (L.O.I.): a known amount of sample is heated in a furnace at

950°C for about 4 hours, after overnight drying in an oven at 110 °C to drive away adsorbed moisture (H₂O−).

 

b. Sample preparation for XRF analysis: samples for XRF analysis are pressed powder pellets obtained with 4 grams of homogenized powder (to maintain the statistical value of the original sample) and pressed to obtain a tablet.

 

c. Sample analysis using the Axios Panalytical spectrometer.

Elements analysed                         Detection limit

SiO₂     wt.%                                        > 130 ppm

TiO₂     wt.%                                        > 10 ppm

Al₂O₃   wt.%                                        > 85 ppm

Fe₂O_3t  wt.%                                       > 16 ppm

MnO    wt.%                                        > 6 ppm

MgO    wt.%                                        > 85 ppm

CaO     wt.%                                        > 35 ppm

Na₂O   wt.%                                        > 85 ppm

K₂O      wt.%                                        > 40 ppm

P₂O₅    wt.%                                        > 30 ppm

Rb        ppm                                        > 1 ppm

Sr         ppm                                        > 1 ppm

Y          ppm                                        > 0.7 ppm

Zr        ppm                                        > 1.8 ppm

Nb       ppm                                        > 0.8 ppm

Ba        ppm                                        > 15 ppm

Cr        ppm                                        > 2.5 ppm

Ni        ppm                                        > 1.8 ppm

Sc        ppm                                        > 2.7 ppm

V          ppm                                        > 5 ppm

Co        ppm                                        > 0.8 ppm

Cu        ppm                                        > 0.8 ppm

Zn        ppm                                        > 2 ppm

Ga       ppm                                        > 1 ppm

La        ppm                                        > 15 ppm

Ce        ppm                                        > 10 ppm

Yb        ppm                                        > 0.5 ppm

Hf        ppm                                        > 0.5 ppm

Ta        ppm                                        > 0.8 ppm

Pb        ppm                                        > 1 ppm

Th        ppm                                        > 3.5 ppm

U         ppm                                        > 0.8 ppm

F          ppm                                        > 25 ppm

Cl         ppm                                        > 1 ppm

S          ppm                                        > 1 ppm

According to the Radioprotection regulations, access for non-classified personnel (visitors) is permitted provided they are accompanied by laboratory personnel. Access is forbidden to pregnant visitors.

Fig.1 Axios Panalytical sequential wavelength dispersion spectrometer

 

Fig.2 PC in communication with the spectrometer via SuperQ program