Temperature and magnetic field diagnostics
Laser spectroscopy reveals the composition of layers formed on inner walls of fusion reactors
Laser-induced breakdown spectroscopy (LIBS) has been developed at VTT as a tool for monitoring the surface composition, especially the accumulation of radioactive tritium, on the plasma-facing components inside fusion reactors. The work is done under EUROfusion as a joint effort between more than ten laboratories from different European countries. The unique feature of the LIBS setup at VTT is the possibility to analyse samples containing activated or poisonous materials, including tritium and beryllium. For this purpose, a dedicated system has been built consisting of a Nd:YAG laser producing nanosecond pulses, an ultrahigh vacuum chamber, and a Czerny-Turner-type spectrometer connected with an intensified CCD camera, optimised to produce a high spectral resolution for the different hydrogen isotopes. Besides fusion-relevant samples, the system can be applied to a variety of material samples with complex geometries.
+358 400 102 840