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Wirtz M.,Jülich Research Center | Linke J.,Jülich Research Center | Pintsuk G.,Jülich Research Center | Rapp J.,FOM Instituut voor Plasmafysica Rijnhuizen | And 2 more authors.
Journal of Nuclear Materials | Year: 2012

The influence of high flux hydrogen-plasma on the thermal shock behaviour of tungsten was investigated in a combined experiment using the linear plasma device Pilot-PSI and the electron beam facility JUDITH 1. Tungsten targets were exposed to high flux hydrogen plasma, cyclic thermal shock tests and a combination of both loading conditions. The induced thermal shock crack networks and surface modifications were investigated and characterised using scanning electron microscopy (SEM), optical microscopy and laser profilometry. Comparisons of the results showed that the combination of hydrogen plasma and thermal shock loading has a significant influence on the crack pattern in terms of crack distance, width and depth. Furthermore the sequence of the different loading types is of importance. Due to the prior loading with hydrogen plasma the thermal shock cracks were not limited to the electron beam loaded area but propagated through the just plasma loaded area and even through the unexposed area at the edges of the tungsten target. © 2011 Elsevier B.V. All rights reserved.

Dain R.P.,Wichita State University | Leavitt C.M.,Wichita State University | Leavitt C.M.,Yale University | Oomens J.,FOM Instituut voor Plasmafysica Rijnhuizen | And 3 more authors.
Rapid Communications in Mass Spectrometry | Year: 2010

The structures of gas-phase, metal chlorate anions with the formula [M(ClO3)2], M 1/4Na and K, were determined using tandem mass spectrometry and infrared multiple photon dissociation (IRMPD) spectroscopy. Structural assignments for both anions are based on comparisons of the experimental vibrational spectra for the two species with those predicted by density functional theory (DFT) and involve conformations that feature either bidentate or tridentate coordination of the cation by chlorate. Our results strongly suggest that a structure in which both chlorate anions are bidentate ligands is preferred for [Na(ClO3)2]. However, for [K(ClO3)2] the best agreement between exper-imental and theoretical spectra is obtained from a composite of predicted spectra for which the chlorate anions are either both bidentate or both tridentate ligands. In general, we find that the overall accuracy of DFT calculations for prediction of IR spectra is dependent on both functional and basis set, with best agreement achieved using frequencies generated at the B3LYP/6-311Rg(3df) level of theory. © 2009 John Wiley & Sons, Ltd.

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