Surface temperature measurement of plasma facing components with pulsed active pyrometry

In fusion devices, like Tore Supra, the surface temperature of the carbon plasma facing components (PFC) is measured by standard infrared (IR) system in real time for control of integrity of PFCs. The emissivity of carbon is known and high (ε∼0.8–0.9) and therefore the contribution of the reflected flux in the total flux collected can be neglected. For future tokamaks like WEST and ITER, PFCs will be in metal (Be/W) with low and variable emissivities (ε∼0.1–0.4). Consequently, the surface temperature measurement will become challenging due to low emissivity and non-negligible reflected fluxes. The pulsed active pyrometry proposed in this paper allows a punctual surface temperature measurement independently of the emissivity and the reflected fluxes. Experimental results for aluminium and tungsten samples are reported. In addition it is shown that using the local measurement by active pyrometry, an overall 2D standard IR perturbed by a reflected flux can be corrected to recover the full 2D real surface temperature.