We report for the first time on the ability of Raman microscopy to give information on the structure and composition of Be related samples mimicking plasma facing materials that will be found in ITER. For that purpose, we investigate two types of material. First: Be, W, Be 1 W 9 , and Be 5 W 5 deposits containing a few percents of D or N, and second: a Mo mirror exposed to plasma in the main JET chamber (in the framework of the first mirror test in JET with ITER-like wall). We performed atomic quantifications using ion beam analysis for the first samples. We also did atomic force microscopy. We found defect induced Raman bands in Be, Be 1 W 9 , and Be 5 W 5 deposits. Molybdenum oxide has been identified showing an enhancement due to a resonance effect in the UV domain.

We herein report on the formation of BeD2 nanocrystalline domes on the surface of a beryllium sample exposed to energetic deuterium ions. A polycrystalline beryllium sample was exposed to D ions at 2 keV/atom leading to laterally averaged deuterium areal densities up to 3.5 10(17) D cm(-2), and studied using nuclear reaction analysis, Raman microscopy, atomic force microscopy, optical microscopy and quantum calculations. Incorporating D in beryllium generates a tensile stress that reaches a plateau at  ≈1.5 10(17) D cm(-2). For values higher than 2.0 10(17) cm(-2), we observed the growth of  ≈90 nm high dendrites, covering up to 10% of the surface in some zones of the sample when the deuterium concentration was 3  ×  10(17) D cm(-2). These dendrites are composed of crystalline BeD2, as evidenced by Raman microscopy and quantum calculations. They are candidates to explain low temperature thermal desorption spectroscopy peaks observed when bombarding Be samples with D ions with fluencies higher than 1.2 10(17) D cm(-2).

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This work investigates the structural, magnetic and magneto-optical properties of a new zinc phosphate-tellurite glass belonging to the 45ZnO-10Al2O3-40P2O5-5TeO2 system. The glass was prepared by a wet method of processing the starting reagents followed by suitable melting–stirring–quenching–annealing steps. Specific parameters such as density, average molecular mass, molar volume, oxygen packaging density, refractive index, molar refractivity, electronic polarizability, reflection loss, optical transmission, band gap and optical basicity have been reported together with thermal, magnetic and magneto-optical characteristics. Absorption bands appear in the blue and red visible region, while over 600 nm the glass becomes more transparent. FTIR and Raman spectra evidenced phosphate-tellurite vibration modes proving the P2O5 and TeO2 network forming role. Magnetic measurements reveal the diamagnetic character of the Te-doped glass with an additional weak ferromagnetic signal, specific to diluted ferromagnetic oxides. Positive Faraday rotation angle with monotonous decreasing value at increasing wavelength was evidenced from magneto-optical measurements. The final product is a composite material comprising of a non-crystalline vitreous phase and Te-based nanoclusters accompanied by oxygen vacancies. The metallic-like Te colloids are responsible for the dark reddish color of the glass whereas the accompanying oxygen vacancies might be responsible for the weak ferromagnetic signal persisting up to room temperature.

This study demonstrates that Raman microscopy is a suitable technique for future post mortem analyses of JET and ITER plasma facing components. We focus here on laboratory deposited and bombarded samples of beryllium and beryllium carbides and start to build a reference spectral databases for fusion relevant beryllium-based materials. We identified the beryllium phonon density of states, its second harmonic and E 2G and B 2G second harmonic and combination modes for defective beryllium in the spectral range 300-700 and 700-1300 cm -1 , lying close to Be-D modes of beryllium hydrides. We also identified beryllium carbide signature, Be 2 C, combining Raman microscopy and DFT calculation. We have shown that, depending on the optical constants of the material probed, in depth sensitivity at the nanometer scale can be performed using different wavelengths. This way, we demonstrate that multi-wavelength Raman microscopy is sensitive to in-depth stress caused by ion implantation (down to ≈30 nm under the surface for Be) and Be/C concentration (down to 400 nm or more under the surface for Be+C), which is a main contribution of this work. The depth resolution reached can then be adapted for studying the supersaturated surface layer found on tokamak deposits.2