Use of the near vacuum UV spectral range for the analysis of W-based materials for fusion applications using LIBS

The vacuum UV (VUV)-near Infrared (NIR) laser induced breakdown spectroscopy (LIBS) technique was applied to investigate the composition of W-based samples with a protective carbon layer. The sample was analyzed under pressures from 5 to 10⁵ Pa and atmosphere (air, He). The spectra were recorded with three spectrometers at delays from 200 ns to 10 μs at atmospheric pressures and from 100 to 500 ns at low pressures. The electron density was determined from the measured spectra using Stark broadening and the electron temperature from the W I-W III Saha-plot in the VUV-NIR spectral range. The better precision was achieved due to usage W III spectral lines of tungsten. The achieved results are more reliable than results obtained without W III spectral lines. The calibration free LIBS method was then applied to determine the W and C contents of the analyzed sample.