title: A LIBS method for simultaneous monitoring of the impurities and the hydrogenic composition present in the wall of the TJ-II stellarator.
abstract: The study of plasma-wall interactions and impurity transport in the plasma fusion devices is critical for the development of future fusion reactors. An experiment to perform laser induced breakdown spectroscopy, using minor modifications of our existing laser blow-off impurity injection system, has been set up thus making both experiments compatible. The radiation produced by the laser pulse focused at the TJ-II wall evaporates a surface layer of deposited impurities and the subsequent radiation produced by the laser-produced plasma is collected by two separate lens and fiber combinations into two spectrometers. The first spectrometer, with low spectral resolution, records a spectrum from 200 to 900 nm to give a survey of impurities present in the wall. The second one, with high resolution, is tuned to the wavelengths of the Hα and Dα lines in order to resolve them and quantify the hydrogen isotopic ratio present on the surface of the wall. The alignment, calibration, and spectral analysis method will be described in detail. First experimental results obtained with this setup will be shown and its relevance for the TJ-II experimental program discussed.
authors.affiliation: Laboratorio Nacional de Fusión, CIEMAT, Av. Complutense, 40, 28040 Madrid, Spain.
authors.forename: B
authors.initials: B
authors.lastname: López-Miranda
authors.affiliation: Laboratorio Nacional de Fusión, CIEMAT, Av. Complutense, 40, 28040 Madrid, Spain.
authors.forename: B
authors.initials: B
authors.lastname: Zurro
authors.affiliation: Laboratorio Nacional de Fusión, CIEMAT, Av. Complutense, 40, 28040 Madrid, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Baciero
authors.affiliation: Universidad Carlos III de Madrid, Av de la Universidad, 30, 28911 Leganés, Madrid, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Martínez