MICROWAVE-ENHANCED LASER-INDUCED BREAKDOWN SPECTROSCOPY OF ZIRCONIUM

Abstract

We developed a microwave-enhanced laser-induced breakdown spectrometer (MW-LIBS) to produce strong emission intensities and a high signal-to-noise ratio (SNR) for spectrochemical and analytical applications inside the Fukushima Daiichi Nuclear Power Station (FDNPS). The MW-LIBS potentially solves the signal attenuation problem of fiber-coupled LIBS, which may experience deterioration in an intense radiation environment. This study's target material is Zirconium (Zr) metal used as the nuclear fuel tube cladding. Measurements of the emission intensity enhancement factor and SNR of the Zr are demonstrated for increasing microwave power. Results indicate enhancement in emissions of SNR of atomic Zr I and ionic Zr II increasing several hundred times higher compared with the standard LIBS. The interaction of the microwave and the plasma enhances the excitation and recombination cycle of the Zr I. Consequently, the ionization and molecular ZrO radical formation were also enhanced and sustained for a more extended period. The lifetime of the emissions lasted more than the microwave duration of 1000 μs. The microwaves also enlarged the plasma 20 times its initial volume.