A Nd-YAG laser operating at 532 nm with a maximum intensity of 10 10 W/cm 2 was used to ablate aluminium and tantalum targets placed in vacuum. A mass quadrupole spectrometer (MQS) at high sensitivity, operating in the range of 1-300 amu, with a resolution better than 1 amu, was used to analyse the atomic emission produced by the laser ablation. The neutrals' emission produced by laser-generated plasma at INFN-LNS was investigated in terms of temperature, ablation yield, angular distribution and velocity. The neutrals' detection through the MQS permitted to measure the mass energy distribution. Results demonstrate that the maximum temperatures of the neutral species are of the order of 100 eV. The angular emission of neutrals is peaked along the normal to the target surface, as it was observed for the ions; the ablation yield increases suddenly at low laser intensity and decreases at high laser intensity, owing to the higher ionization processes; the flow velocity follows the adiabatic expansion of the plasma in vacuum and it is of the order of 10 4 m/s. Measurements will be presented and discussed, according to the available models.
Neutrals' temperature in laser-generated plasma at LNS
Caridi F.;Torrisi L.;
2005-01-01
Abstract
A Nd-YAG laser operating at 532 nm with a maximum intensity of 10 10 W/cm 2 was used to ablate aluminium and tantalum targets placed in vacuum. A mass quadrupole spectrometer (MQS) at high sensitivity, operating in the range of 1-300 amu, with a resolution better than 1 amu, was used to analyse the atomic emission produced by the laser ablation. The neutrals' emission produced by laser-generated plasma at INFN-LNS was investigated in terms of temperature, ablation yield, angular distribution and velocity. The neutrals' detection through the MQS permitted to measure the mass energy distribution. Results demonstrate that the maximum temperatures of the neutral species are of the order of 100 eV. The angular emission of neutrals is peaked along the normal to the target surface, as it was observed for the ions; the ablation yield increases suddenly at low laser intensity and decreases at high laser intensity, owing to the higher ionization processes; the flow velocity follows the adiabatic expansion of the plasma in vacuum and it is of the order of 10 4 m/s. Measurements will be presented and discussed, according to the available models.Pubblicazioni consigliate
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