Deposited layer removal by laser ablation: from laboratory to Tore Supra integration

In-vessel carbon layer removal by using laser ablation is for the first time presented here. However, prior to these tests, careful virgin carbon fiber composite (CFC) tile studies were carried out in order to determine the bulk ablation threshold fluence. Then, laser ablation was applied to Tore Supra at a laser fluence below that value in order to protect the bulk material. It is shown that layers of up to 50 μm are easily removed. Use of several metrology techniques such as confocal microscopy and IR measurements enabled the local determination of the deposited material, confirmation of the layer removal and determination of the depth of the layers removed. Within the accuracy of these measurements, the bulk has not been eroded.