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A detailed look beneath the surface: Evidence of a surface reconstruction beneath a capping layer
(2016)
The mechanical set up of a novel scanning reflection X-ray microscope is presented. It is based on zone plate optics optimized for reflection mode in the EUV spectral range. The microscope can operate at synchrotron radiation beamlines as well as at laboratory-based plasma light sources. In contrast to established X-ray transmission microscopes that use thin foil samples the new microscope design presented here allows the investigation of any type of bulk materials. Importantly, this permits the investigation of magnetic materials by employing experimental techniques based on the X-ray magnetic circular dichroism (XMCD), the X-ray linear magnetic dichroism or the transversal magneto-optical Kerr effect (T-MOKE). The reliable functionality of the new microscope design has been demonstrated by T-MOKE microscopy spectra of Fe/Cr-wedge/Fe trilayer samples. The spectra were recorded at various photon energies across the Fe 3p edge revealing the orientation of magnetic domains in the sample.
In this paper a novel concept of ablation cell for laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is presented. Suppression of the turbulence in the flush gas flow in the ablation region reduces the wash-out time of the ablation cell considerably. An ablation chamber which enables ICP-MS pulse duration down to several ten milliseconds has been designed. Dependence of the ICP-MS peak amplitude, width, and shape on the gas flow parameters is studied experimentally for aerosol ablated under laminar and turbulent conditions. Experiments demonstrate that the ICP-MS peak becomes sharper and the amplitude of the signal grows as the turbulence in the ablation cell is suppressed. Furthermore, the possibility of the LA-ICP-MS analysis with a sampling rate of more than 10 Hz has been demonstrated. Express in-depth profiling in the new ablation cell is demonstrated on examples of an Al -Zn multilayer structure and an industrial Mg -Zn coating.
Image-sharpness metrics can be used to optimize optical systems and to control wavefront sensorless adaptive optics systems. We show that for an aberrated system, the numerical value of an image-sharpness metric can be improved by adding specific aberrations. The optimum amplitudes of the additional aberrations depend on the power spectral density of the spatial frequencies of the object.