Basic study on laser ablation surface cleaning of nuclear facility

An ultra short pulsed Nd:YAG laser was employed to study the ablation effec ts and laser beam transport in optical fibres. Using 13 mum Zn coated carbo n steel cis a target, the relationship between ablation rate and laser flue nce was investigated, and optimal processing conditions were determined. Th e laser induced products consisted of vapour and liquid particles. It was f ound that a smaller incident laser angle was more suitable for protecting t he focusing lens from the pollution of the ablated products. The collection rate of the ablated products almost reached 100%. Additionally, a laser be am of other 5.6 W in power with a transportation rate of nearly 90% was out put at the end of a 20 in long optical fibre. By this output power, a Zn co ating of the same thickness could be completely ablated. A decontamination factor was introduced to estimate the cleaning effects of laser ablation, a nd satisfactory cleaning was obtained.