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Abstract No.: ThP-155
Session: Materials Science
Presentation date: Thu, Aug 31, 2006
Presentation time: 09:50 – 11:20

Determinations of Thermal-to-Plasma Transitions and Implications in Laser-matter Interaction by Coincidence Ion-photon Measurements

Jose Miguel Vadillo1, Jose Francisco Alcantara-Leiva1, Carmen Cecilia Garcia1, Jose Javier Laserna1

1 Universidad de Malaga, Malaga, Spain

Correspondence address: Jose Francisco Alcantara-Leiva, Universidad de Malaga, Quimica Analitica, Campus de Teatinos, Malaga, 29071 Spain.

Keywords: Ionization Threshold; Laser Ablation; Laser Ionization; Surface Analysis.

Novel aspect: Simultaneous determination of plasma formation and ion formation in laser matetr interaction.

 

It is generally accepted that laser-solid interaction is based on a thermal process, where a result of the laser impact onto the slid target, the temperature rises, and eventually the target can melt and even vaporize. Under this assumption, the amount of energy reaching a solid sample greatly influences the type of phenomena occurring at the sample surface. While at high irradiance regime extensive fragmentation, particle emission, and plasma formation is the dominant situation, at low irradiance levels, surface desorption and thermoemission are the common processes. As laser irradiance increases, different sequential processes occur that in the simplest picture involves the following macroscopic events: surface heating with thermal desorption, surface melting with surface evaporation, volume evaporation, formation of an optically thick plume, plasma absorption and optical breakdown. As monitoring of laser-produced events in direct solid analysis is commonly carried out by atomic emission spectroscopy or mass spectrometry, and ion formation and plasma formation take place at different fluence intervals, it is interesting to determine precisely the transition between the different regimes in order to tune the excitation conditions to the analysis needs.

This work describes the development of a simultaneous multichannel optical emission spectroscopy/time-of-flight mass spectrometry coincidence for different metallic targets using nanosecond laser pulses to determine the different found regimes in the range fluence region we may use to produce it. It also describes an application of the developed mass spectrometer to in-depth analysis of layered metallic materials