Emission characteristics of gadolinium plasma in orthogonal double-pulse laser breakdown spectroscopy using femto and nanosecond laser (Contract research)

Maruyama, Yoichiro; Oba, Masaki ; Akaoka, Katsuaki ; Miyabe, Masabumi   ; Wakaida, Ikuo  

Emission characteristics of gadolinium plasma in the double-pulse LIBS using a femtosecond laser as an ablation source have been studied to achieve high sensitivity for analyzing next generation nuclear fuel in a future. In experiment, effects of the ablation laser focusing lens position and relative position of two plasmas were studied. The optimum ablation laser focusing lens position was about 22 mm from the sample surface, and the emission was maximized with the x of 1-1.2 mm and the y of 0.5-1 mm. As a result, about 200-times higher emission intensity in the double-pulse reheating mode was obtained than the emission in the single-pulse method. Moreover, the spectral width of the emission did not depend on the reheating laser pulse energy, and the high emission intensity could be obtained without the spectral broadening.