Measurements Of Deuterium Retention And Surface Elemental Composition With Double Pulse Laser Induced Breakdown Spectroscopy

Estimating the tritium amount retained in the plasma facing components and their surface layer composition is of crucial importance for ITER. Laser-induced breakdown spectroscopy (LIBS) is an analytical technique suitable for in situ measurements of both these quantities. For improving its sensitivity, the double pulse (DP) variant can be used, instead of the standard single pulse (SP). In this work Mo samples coated with 1.5-1.8 mu m thick W-Al (as a proxy for Be) mixed layer, with co-deposited deuterium were analyzed under vacuum (similar to 5. x. 10(-5) mbar) by SP and DP LIBS, showing enhancement of the spectral intensity for the latter. Calibration free method was applied to the LIBS data for getting the elemental concentration of W and Al. Results are in satisfactory agreement with those obtained from preliminary, ion beam analysis measurements. Deuterium concentration was tentatively estimated by accounting for the intensity ratio between Da and nearby WI lines.