| الوصف: |
Laser capabilities to eliminate contaminants and deterioration products from the surface of material without altering the material surface makes this technology an ultimate cleaning solution for archaeological material conservation. Among the other main parameters that work for controlled laser cleaning, pulse repetition rate plays an important role [1][2]; keeping pulse energy below the plasma formation threshold, sub-nanosecond high-repetition rate could act to power up the efficiency of archaeological material cleaning by n-IR laser. Though some parameters are governed by fluence as well as by the technically fixed data of built-in laser equipment for laser cleaning intervention, the ablation threshold of the materials could be deduced after irradiation with a series of laser pulses [3]. Hence, materials thermal properties introduce structural defects even if the absorbed laser energy is below the damage threshold. This paper proposes new possibilities of using pulse mode n-IR Laser with sub-nanosecond high-repetition-rate which could offer more potentials for minimal interventions of Archaeological material conservation. The work includes significant Pleistocene bones and Neogene flints from Sierra de Atapuerca case study to assess the proposed laser parameters; results will be clearly outlined to demonstrate the usefulness of the high- repetition-rate lasers with low pulse energy in application and open to progress more effective, operative and safer laser cleaning profiles. [1] G. Raciukaitis, M. Brikas, P. Gecys, and M. Gedvilas, “Accumulation effects in laser ablation of metals with high-repetition-rate lasers,” High-Power Laser Ablation VII, vol. 7005, no. May, p. 70052L, 2008. [2] M. A. Iglesias-Campos and J. L. Prada-Pérez, “Actual laser removal of black soiling crust from siliceous sandstone by high pulse repetition rate equipment: Effects on surface morphology,” Mater. Constr., vol. 66, no. 321, 2016. [3] C. Emmelmann and J. P. C. Urbina, “Analysis of the influence of burst-mode laser ablation by modern quality tools,” Phys. Procedia, vol. 12, no. PART 2, pp. 172–181, 2011. |
