Removal of Deposits from Diagnostic Mirrors employing an Nd:YAG Laser

A noninvasive laser ablation process for the removal of deposited carbon and beryllium particles on diagnostic mirrors is investigated in support of ITER and other similar fusion devices. The need to maintain in-vessel mirrors in a clean and reflective condition is critical when such surfaces are required to reflect plasma light to appropriate diagnostic systems. A configuration including a q-switched 1064nm Nd:YAG laser coupled to a quartz fiber optic, laser scanning system, and lens will be employed to determine optimal conditions for the ablation of deposited particles, while mitigating physical effects on the mirror surface. The effectiveness of this in situ cleaning method will be evaluated while varying such parameters as the laser focus, scanning speed, pulse frequency, and surface temperature.