Li K Emissions Detection In Various Compounds Using A Reflection Zone Plate Spectrometer
Khalil HASSEBI1, Nicolas RIVIDI2, Anne VERLAGUET3, Alexei ERKO†4, Juergen PROBST5, Heike LOECHEL5, Thomas KRIST5, Philippe JONNARD1
- Laboratoire de Chimie
Physique—Matière et Rayonnement, Faculté des Sciences et Ingénierie,
Sorbonne Université, UMR CNRS, 4 Place Jussieu, , 75252 Paris Cedex 05,
- Service Camparis, UMS 7154—CNRS, OSU Ecce Terra, Sorbonne Université, 4 place Jussieu, 75005 Paris, France
- Sorbonne Université, CNRS-INSU, Institut des Sciences de la Terre de Paris, ISTeP UMR 7193, F 75005 Paris, France
- Institut fuer Angewandte Photonik e. V., Rudower Chaussee 29-31, D-12489 Berlin, Germany
- Nano Optics Berlin GmbH, Krumme Str 64, D-10627 Berlin, Germany
Soft x-ray emission spectroscopy (XES) is a technique used
to study the electronic structure of materials. It measures the energy
spectrum of emitted x-rays from a sample. It is performed by
irradiating the sample with ionizing particles (electrons in our case)
and measuring the energy distribution of the x-rays that are
subsequently emitted. The emitted x-rays are characteristic of the
electronic states of the sample, thus, the presence of an element can
be detected and could be also used to perform quantitative analysis.
Reflection zone plates (RZP) can be used in XES as a
wavelength-dispersive element . They consist of a series of
concentric zones, each with a slightly different thickness. When x-rays
are incident on the zone plate, the different zones act as diffraction
gratings, causing the x-rays to diffract and interfere with one another
while focusing them at the same time. They have higher spectral
resolution and cover wider energy ranges compared to other optical
elements such as periodic multilayers. RZPs allow the reach of energy
resolutions as low as 0.49 eV at the Al L2,3 line (around 72 eV) .
With parallel detection of x-rays in contrast to conventional
wavelength dispersive spectroscopy (WDS) spectrometers with a
dispersive crystal (or multilayer) based on Rowland mounting they do
not have a scanning mechanism.
In this work, we demonstrate the use of a Fresnel (RZP)
implemented in an electron microprobe for the detection of Li K
(around 50-55 eV) emission in different lithium compounds. Li K
emission is a characteristic emission band produced when Li 1s levels
are ionized inside the material. However, it can be challenging to
detect this emission due to its low fluorescence yield, re-absorption
effects, and the presence of other spectral lines in the same energy
range. We report on our measurements of the Li K emission bands in
several lithium compounds with an RZP spectrometer. Our results
demonstrate this approach’s potential for various applications in the
field of x-ray spectroscopy.
Acknowledgment: This research was funded by Agence Nationale de la Recherche in the framework of the SQLX Project (ANR-20-CE29-0022).
 A. Erko et al., Opt. Express, vol. 22, no. 14, p. 16897, Jul. 2014, doi: 10.1364/OE.22.016897.
 A. Hafner et al., Opt. Express, vol. 23, no. 23, p. 29476, Nov. 2015, doi: 10.1364/OE.23.029476.