Research - SOLARIS National Synchrotron Radiation Centre - Jagiellonian University

First XAFS spectrum on SOLABS beamline

At the beginning of October, we could admire the first monochrome beam of radiation at the monochromator output of the newly constructed SOLABS beamline. However, the work on the beamline has not slowed down and we are happy to inform you that on Friday, October 15, thanks to the efforts of the entire team, the theoretical assumptions, made during the construction of the beamline, were confirmed in the experiment, during which the XAFS spectrum (X-ray absorption fine structure) was measured. This was the spectrum for the K-absorption edge of titanium, measured in two measurement modes - in transmission mode (blue spectrum) and by measuring the total sample current (TEY, Total Electron Yield) (red spectrum). The artifact visible in the blue spectrum at 4925 eV is the result of using only one ionization chamber not isolated from the sample chamber. In the transmission mode (classical absorption measurement) the X-ray photons transmitted through the titanium foil were investigated, while in the TEY mode the total electron yield on the sample was measured.

The transmission mode is the simplest and most accurate method of samples measurement with a high concentration of the absorber element (> 3-5%). Measurements in this mode are volume-sensitive due to the large penetration depth of the X-rays, and at the same time require homogeneous and sufficiently thin samples for the X-rays to pass through them.

In the case of the TEY measurement mode, surface sensitivity can be achieved by measuring electrons emitted from the sample surface. In this mode, there is no restriction to the thickness and homogeneity of the sample. Additionally, the signal intensity is higher as all electrons emitted from the sample are measured: photoelectrons, Auger electrons and secondary electrons. Nevertheless, the TEY measurement mode is limited to conductive samples.

Pierwsze widmo XAFS na linii SOLABS

Soon, as part of the beamline calibration, measurements will be made for some elements of group 3d of the periodic table, from Ti to Mn, in the energy range (2300 - 7200) eV. The team of the beamline will then prepare to measure p-group elements such as sulfur and chlorine compounds at lower energy values. We are already waiting for further progress of work on the SOLABS beamline, aimed at finally making it available to Users from Poland and around the world.

Published date 19/10/2021 - Sylwia Orzechowska

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