The effect of instrument parameters of x-ray fluorescence wavelength-dispersive spectrometer on the metrological characteristics of measurements

The effect of the instrument parameters (such as types of the detectors, crystal analyzers, and primary radiation filters, as well as x-ray tube operation modes, angular spread of collimators and settings of the window of the amplitude analyzer) of an x-ray fluorescence wavelength-dispersive spectrometer on the fluorescence intensity is shown using the literature data. Adjustment of the corresponding nodes of the spectrometer can result in improvement of the metrological characteristics of measurements. The influence of the aforementioned nodes and time of exposure on the metrological characteristics of measurements is exemplified in determination of Al, Si, Ti, Fe and Sn content in a range of 10^-2 -10^-3 % in potassium fluorozirconate. Determined values of the contrast of the analytical signal, detection limit and standard deviation of the results showed that the effect of the instrumental parameters of the spectrometer is critical only when the content of the elements is lth3 % or less. The optimal operation modes of the x-ray tube depend on the atomic number of the element, e.g., for light elements it is advisable to use a higher current strength at a lower voltage, whilst filters of primary radiation have no positive effect. The best characteristics of the measurement results were obtained with LiF200 crystal-analyzer and 0,25\i collimator. Settings of the amplitude discriminator to a hall-width of the peak are preferable, but at extremely low intensities of the analytical signal, comparable to the background, the opposite situation occurs. The exposure time also significantly affects the spread of measurements only at a 10^-3 % element content region which entails the necessity of increasing the measurement time up to more than 90 seconds. However, for tin due to extremely low contrast, an increase in the exposure time to more than 60 seconds does not reduce the spread of measurement results.

1. Afonin У Р., Gunicheva Т. N., Piskunova L. F. X-ray Fluorescence Silicate Analysis. — Novosibirsk: Nauka, 1984. — 227 p. [in Russian],

2. Woldseth R. X-Ray Energy Spectrometry. — Burlingame, CA: Kevex Corp., 1973. — 323 p.

3. Mazuritskiy M, I. Methods of X-Ray Focusing and Spectral Analysis / Soros. Obrazovat. Zh. 2001. Vol. 7. N 10. E 95 - 101 [in Russian].

4. Mikhailov I. F. X-Ray Methods of Analysis of Material Composition. Monograph. — Kharkov: Pidruchnik, 2015. — 204 p. [in Russian]

5. Suvorova D. S. Selection of Optimal Conditions and Development of Methods of X-ray Fluorescence Determination of Low Contents of Rare Elements in Rocks: Author’s abstract from Chem. Sci. Cand. Dissertation PhD Thesis in chemistry. — Irkutsk, 2017. — 19 p. [in Russian].

6. Chemorukov N. G., Nipruk, О. У Theory and Practice of X-ray Fluorescence Analysis: Guide for students. — Nizhny Novgorod: N. I. Lobachevsky Nizhny Novgorod State University, 2012. — 57 p. [in Russian],

7. Namestnikova A. A., Goncharenko G. A., Tikhova T. Yu. Analysis of Copper Alloys by Methods of X-ray Fluorescence and Emission Spectroscopy in the JSC “Severstal” / Zavod. Lab. Diagn. Mater. 2006. Vol. 72. N 1. E 21 - 23 [in Russian].

8. Betenekov N. D., Denisov E. I., Puzako У D. Elements of Radiometry and Spectrometiy of Ionizing Elements: Guide for Students. — Yekaterinburg: Izd. UGTu, 2004. — 65 p. [in Russian],

9. Ivanov A. N. Diffraction Methods of Materials Research. Compendium of Lectures. — Moscow: Moscow Institute of Steel and Alloys, 2008. 99 p. [in Russian],

10. Shendrik R. Yu. Methods of Experimental Condensed Matter Physics. Part 3. Introduction to the Physics of Scintillators. — Irkutsk: Irkutsk State University, 2013. — 110 p. [in Russian],

11. Smagunova O. N., Karpukova О. M. Methods of Mathematical Statistics in Analytical Chemistry. — Rostov-on-Don: Fe-niks, 2012. — 346 p. [in Russian],

12. Mamikonyan S. У Equipment and Methods of fluorescent X-ray Radiometric Analysis. — Moscow: Atomizdat, 1976. — 280 p. [in Russian],

13. Goldstein J., Newbury D., Joy D., et al. Scanning Electron Microscopy and X-ray Microanalysis. 3rtl edition. — Kluwer Academic, 2003. — 689 p.

14. Proc. of Sixth Annual Seminar “Spectrometric Analysis. Equipment and Data Processing by PC", November 22 - 26,1999 / Karpenko A. Ya. (edi). — Obninsk: GCIPK, 2000. — 112 p. [in Russian].

15. MP-242-1691-2013. Method of verification. X-Ray Fluorescence Spectrometers ARL 9800, ARL 9900, ARL Advant’X. — St. Petersburg: D. I. Mendeleev VNIIM, 2013. 7 p. [in Russian].