DETEKSI EFEK KONTAMINASI HARMONIK RADIASI SYNCHROTRON PADA DATA SERAPAN SINAR-X STRUKTUR HALUS

Redi K. Pingak

Abstract


Harmonic contamination of synchrotron radiation needs to be detected and corrected because x-ray passing through the monochromator may still have higher order harmonics in addition to its fundamental energy. Here, detection of the harmonic effect on X-ray Absorption Fine Structure Data (XAFS) of Ni(II)-bis-(n-isopropylsalicylaldiminato) was done using the X-ray Extended Range Technique (XERT). The method utilised aluminum foils with various thicknesses mounted in daisy wheels, used to investigate the gradient differences in absorption coefficient vs aluminum thickness plots. The Beer-Lambert equation had to be modified dan fitted to find the harmonic fractions of the beam. These values were then interpolated to account for other energies where the effect was dominant. The results showed that the effect was dominant between 8.5 keV and 13.5 keV, with harmonic fractions being about 0.02 % - 0.04 %. In contrast, there was no such effect found between 13.50 keV and 19.00 keV. To conclude, harmonic contamination was found to be in energy range that was vital for XAFS analysis for Ni(II) complex and thus had to be removed from the measured data.

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