The effect of ablation angle on intensity of laser-induced breakdown spectroscopy under vacuum

The in situ diagnostic of the composition and content of the first wall materials in tokamak devices is an important research interest of the plasma-wall interaction. Laser-induced breakdown spectroscopy (LIBS) has become an attractive tool for in situ diagnostic of the first wall materials. It has the ability to analyze the composition of the first wall remotely and on-line without sample manipulation or pretreatment. In tokamak, using the LIBS method in a fixed window to diagnose wall materials in different positions will inevitably affect the LIBS measurement signal due to different laser ablation and light collection angles. In this paper, we got the determination of the relationship between the intensity of the tungsten spectral line and laser energy in the laboratory as a prerequisite. And the effects of different ablation angles on the temporal evolution of the spectrum of the laser ablated tungsten material were investigated in detail. This provides a reference for in situ LIBS analysis.