Development of laser induced breakdown spectroscopy for studying erosion, deposition, and fuel retention in ASDEX Upgrade

• Published in: Fusion engineering and design Vol. 98-99; pp. 1349 - 1352
• Main Authors: Paris, Peeter, Piip, Kaarel, Hakola, Antti, Laan, Matti, Aints, Märt, Koivuranta, Seppo, Likonen, Jari, Lissovski, Aleksandr, Mayer, Matej, Neu, Rudolf, Rohde, Volker, Sugiyama, Kazuyoshi
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.10.2015
• Subjects: Concentration (composition); Data processing; Density; Deposition; Elemental depth profiles; Erosion; Fuel retention; Laser induced breakdown; LIBS diagnostics; Plasma-facing components; Spectra; Spectroscopy; Walls; LIBS diagnostics; Data processing; Fuel retention; Plasma-facing components; Elemental depth profiles
• ISSN: 0920-3796; 1873-7196
• DOI: 10.1016/j.fusengdes.2015.03.004

•LIBS development for in situ monitoring of first walls of fusion reactors.•Testing of samples extracted from the divertor tiles of ASDEX Upgrade.•Reliable detection of deuterium depth profiles.•A method of LIBS data processing which allows to find the elemental depth profiles.•Comparison of LIBS results with those of other surface characterization methods. The paper deals with the development of laser induced breakdown spectroscopy (LIBS) into an in situ method for studying erosion/deposition processes at the first walls of fusion reactors. To this end, samples extracted from the divertor tiles of ASDEX Upgrade after the 2009 plasma operations were analyzed using LIBS for their composition and the results were compared with other post mortem deposition data. Quantitative depth profiles for the elemental concentrations were extracted from LIBS spectra by applying a novel data processing method. In addition, both multiline and multispot averaging procedures were applied to reduce fluctuations in the data. The LIBS concentration profiles matched qualitatively with those given by secondary ion mass spectrometry and quantitatively with the ion-beam data. The deuterium content of the samples could be reliably determined if the surface densities were >1017at/cm2.