Laser-induced plasma emission enhanced by microwaves in argon gas for potential application of nuclear fuel material analysis

Abstract

To perform quantitative analysis of nuclear fuel materials by using laser-induced breakdown spectroscopy (LIBS), emission spectral lines of atoms should be clearly identified, which is far from other atomic and molecular disturbances, low background emission, and optimum emission intensity. To this end, intensified microwaves were introduced into the laser-induced plasma in LIBS. Gadolinium oxide (Gd2O3) was employed for the simulation of nuclear fuel material. Enhancement of laser plasma was obtained when the microwave was introduced into the laser plasma. Total emission intensity of Gd significantly increased for the case of microwave-assisted laser plasma, which revealed that the microwave can effectively be employed to increase the sensitivity. Furthermore, the analytical lines of Gd can be clearly identified, which are far from the molecular bands disturbance and have high emission intensity with low background intensity. The enhancement factors for neutral Gd I at 470.9 nm and ionic Gd II at 458.3 nm were 40 and 45 times for the LIBS with microwaves case. The plasma temperatures were 9500 K and 4800 K for the LIBS with and without microwaves, respectively. The microwave-assisted laser-induced plasma in Ar gas has high potential for the analysis of impurity in nuclear fuel materials.