Desorption of hydrogen from rapidly heated metal foils and wires

Summary form only given. Experiments have been performed to investigate the desorption of hydrogen from rapidly heated metal foils and wires. Metal foils (typically Ti) have been loaded with hydrogen by electrolytic methods. The heating source is a KrF excimer laser which generates up to 600 mJ at pulselengths of 25 ns and a wavelength of 248 nm. Diagnostics utilized to measure hydrogen desorption include intensified, gated CCD optical emission spectroscopy and dye-laser-resonance-absorption photography. Interferometry is also being explored. Densities have been estimated by Stark broadening of hydrogen lines. Typical H streaming velocities are in the range of 2 cm/microsecond. Comparisons will be made to LSP code results. At fluences above the metal ablation threshold, the metal plasma apparently slows the hydrogen expansion. Other experiments have characterized the hydrogen desorption from undoped tungsten foils and wires. The observed, rapid hydrogen desorption from thin tungsten wires could be relevant to the initiation phase of wire z-pinch experiments.