LABORATORY OF X-RAY METHODS

Description from 20.10.2020

In the Laboratory of X-ray Methods, to analyze the composition and structure of matter, the research techniques are used, based on the measurement of the effects accompanying the interaction of X-ray radiation with matter. These techniques include: total reflection X-ray fluorescence analysis (TXRF), wavelength dispersive X-ray fluorescence analysis (WDXRF), and X-ray powder diffraction (XRPD).

In the Laboratory of X-ray Methods, accredited analyzes of the elemental composition of water and cleaned wastewater using the TXRF method and soil using the WDXRF method are performed.

TXRF method – X-ray spectrometer Picofox S2 (Bruker)

In the Picofox S2 spectrometer, the excitation radiation is produced in an X-ray tube with a molybdenum (Mo) anode, with a power of 30 W. The maximum voltage of the lamp is 50 kV, and the maximum intensity is 600 µA. The lamp is air-cooled. The primary radiation, after reflection from the monochromator (radiation monochromatization), is directed at a very small angle (the phenomenon of X-ray total reflection) on a quartz carrier on which the analyzed sample is placed. The characteristic radiation excited in the sample is recorded in the SDD (XFlash) detector placed near to the sample.

Advantages of the method:

• simultaneous measurement of elements from aluminum (Al) to uranium (U) (for technical reasons, except for elements from the range Zr to Ru),
• small required mass/volume of samples: weight from ng to pg, volume in the order of 5-10 ml,
• analysis of liquid samples and mineralizable materials,
• short standard measurement time (~ 15 min),
• high detection limit of a few ppb (0.0000001%).

Types of measured samples:

• environmental and industrial (water, cleaned wastewater, industrial solutions),
• human biological material (blood, serum, urine, hair),
• biological (plant and animal materials).

WDXRF method – X-ray spectrometer AXIOS (PANalytical)

In the Axios spectrometer, the excitation radiation is produced in an X-ray tube with a rhodium anode (Rh) with a power of 2.4 kW. The characteristic radiation emitted from the sample, formed by the collimator system, is directed on the analyzing crystal, which reflects only radiation fulfilling the Bragg condition. The AXIOS spectrometer is equipped with five crystals: LiF (200), Ge (111), PE (002), PX1, LiF (220), enabling the analysis of radiation in a wide range of wavelength (energy). Radiation detection is performed with the use of two X-ray detectors: a flow detector (optimal for elements with an atomic number up to Fe (Z = 26)) and a scintillation detector (for elements heavier than Fe).

Advantages of the method:

• simultaneous measurement of elements from oxygen (O) to uranium (U),
• possible non-destructive analysis,
• analysis of solid samples, powders and liquids,
• standard measurement time (~ 30 min),
• good detectability of a few ppm (0.0001%).

Types of measured samples:

• environmental and industrial (soils, clays, river sediments, minerals),
• industrial (dusts, metals and their alloys, building materials),
• archaeological (coins, ornaments, ceramics),
• biological (plant and animal materials).