Upgraded Bolometer System on JET for Improved Radiation Measurements
In order to test the use of Laser Induced Break-down Spectroscopy technique for codeposited layer studies, under relevant Tokamak conditions, the edge LIDAR laser of JET was used to create a plasma on the surface of an inner leg divertor tile. Part of the tile under observation was equipped with a Tungsten (W) stripe. This was itself covered with a co-deposited layer formed by the plasma interactions after the tile was installed. Preliminary results showed that after a few laser shots the optical signal recorded when ablating the co-deposited layer almost disappeared, indicating that the laser reached the W stripe. These preliminary indications, obtained from limited experiments at JET, constitute a proof of principle that this technique, when implemented in a Tokamak environment, should allow the evaluation of the thickness of a co-deposited layer formed on a tungsten surface.