Tungsten plasma density and temperature time analysis using 1.064 $$\upmu $$m nanosecond dual-pulse laser

Abstract

The information about time evolution of plasma electron temperature and density plays a fundamental role in numerous physics-related sciences. For CF DP-LIBS (calibration-free double-pulse laser-induced breakdown spectroscopy), not only may it serve to minimize the impact on the investigated sample, but also to optimize the laser and spectral parameters, or even to pave the way for real-time chemical analysis of the sample. To evaluate this impact and describe the plasma time behavior, electron temperature and density are calculated for plasma induced by double-pulse Nd:YAG laser with various (0–500 ns) inter-pulse delays. The parameters are calculated using various methods, such as Stark broadening, Boltzmann plot and Saha equation to provide complementary calculations for comparison. To ensure validity of the results, calibration of the measurement setup was performed. In the work, tungsten samples are investigated, because the W is chosen as the preferred material for plasma-facing components in future fusion devices such as ITER. Since LIBS method will be used to monitor tritium retention in ITER, the results may be utilized to improve the diagnostics.

Monitoring of tritium and impurities in the first wall of fusion devices using a LIBS based diagnostic

“…This stage is appropriate for measuring the population of the different internal states of the species enabling the determination of T e and relative concentrations of the different species by means of Boltzmann plots. These processes have been recently characterized in detail in [14]. By utilizing a gateable detector like an ICCD (CCD camera equipped with image intensifier) corresponding spectra can be recorded by inserting a delay (typically 100-1000 ns) between the laser pulse and the gate window of the detector.…”