Double pulse Laser Induced Breakdown Spectroscopy measurements on ITER-like samples

Abstract

Laser Induced Breakdown Spectroscopy (LIBS) is an attractive analytical technique for the in situ analysis of the chemical composition of the components inside the vacuum vessel of ITER and for estimating the tritium content in the machine. To improve its sensitivity a dual pulse (DP) configuration, with two laser pulses delayed in the range of nanosecond to several microseconds can be used.In this work DP measurements carried out jointly by ENEA and IPPLM associations in the frame of EFDA task WP13-IPH-A01-P3-01 on samples resembling ITER in vessel components after material re-deposition (still including carbon) are presented. A DP Nd:YAG laser, operating at 1064nm, with delay between pulses ranging from 20ns to 80ms and pulse duration of 8–12ns was used to interact with tungsten sample coated with 3μm thick mixed layer of C/Al/W (Al was used instead of Be).An enhancement of the spectroscopic emission of the elements was observed compared to the standard LIBS measurements. A Calibration Free method was applied to the data for getting the concentration of each element. Results are in good agreement with the concentrations found by the post-mortem energy dispersive X-ray (EDX) analysis.