One-point calibration laser-induced breakdown spectroscopy for the quantitative analysis of EAST-like plasma-facing materials

Quantitative in situ elemental analyses of the impure deposited layer on the plasma-facing components (PFCs) of magnetically confined fusion devices such as EAST are crucial and challenging. Laser-induced breakdown spectroscopy (LIBS) is one of the most promising methods. In this study, we present an improved quantitative analytic algorithm for the deposited layers (in vacuum) of both major and minor elements via one-point calibration laser-induced breakdown spectroscopy (OPC-LIBS). OPC-LIBS is a variation of the calibration-free LIBS approach involving one matrix-matched standard sample with a known composition that effectively corrects the errors, caused by the uncertainty of Einstein's coefficient and inaccurate efficiency of the spectrum acquisition system of the CF-LIBS method. We found that the OPC-LIBS method is more accurate for the determination of composition of a series of Al-W-Mo coatings (EAST-like deposits) compared to the conventional CF-LIBS approach at 10(-5) mbar to simulate the pressure condition of a fusion vessel. In the case of OPC-LIBS measurement, the relative error of major elements such as Al (85.65-95.51 at%) was below 2%, and the relative error of trace elements W (2.32-9.56 at%) was within 35% and Mo (2.17-11.66 at%) was within 20%. Finally, our results verify the ability of quantitative analysis by using the OPC method in a high-vacuum environment and film samples.