Abstract: A method for reducing outgassing from a metal surface comprises applying energy from an energy source to the metal surface sufficient to melt the metal surface; and allowing the metal surface to re-solidify, wherein the re-solidified metal surface comprises larger grains and fewer grain boundaries, reducing outgassing sites for a trapped gas. Applying energy from an energy source is performed in a raster scan pattern. Adjacent passes in the raster scan pattern overlap sufficiently to melt the entire metal surface. The energy source is a laser, such as a CW Yb fiber laser. A spot size and applied energy of the laser energy source applied to the metal surface is sufficient to melt the entire metal surface (appropriate for the absorption and reflection characteristics of the treated material). The application of energy from an energy source releases at least some of a gas trapped in the metal. The trapped gas is atomic hydrogen. The metal surface comprises an electrode of a high power system device.

Abstract: In a method of detecting the spatial position of a laser beam relative to a body locatable in the path of the laser beam by detecting an acoustic signal produced by the beam in the body, wherein the laser beam carries a power modulation signal and the body has a plurality of acoustic sensors for detecting the acoustic signal produced in the body by the laser beam, the method includes detecting in the outputs of the acoustic sensors signals corresponding to the power modulation of the incident laser beam and detecting any difference in phase between the detected signals. A processor may be provided for processing the outputs of the acoustic sensors, the processor including a sensor for sensing in the respective outputs signals corresponding to the power modulation of the output beam of the laser and a phase sensitive detector for detecting differences in phase between the detected signals.