CHARACTERIZATION OF LASER-GENERATED PLASMA BY ELECTROSTATIC MASS QUADRUPOLE ANALYZER F. Caridi 1,3 , L. Torrisi 1,2 , D. Margarone 1,2 , A. Borrielli 1,3 , S. Gammino 2 , A. Mangione 1,3 and A. Czarnecka 4 1 Dipartimento di Fisica, Università di Messina, Ctr. Papardo 31, Messina, Italy 2 INFN-Laboratori Nazionali del Sud, Via S. Sofia 44, Catania, Italy 3 INFN-Sez. CT, Gr. Coll. di Messina, Ctr. Papardo 31, Messina, Italy 4 Institute of Plasma Physics and Laser Microfusion, Henry Str., Warsaw, Poland Abstract A study of laser ablation in vacuum of different targets (Al, Ni and Ta) by using 3 ns Nd:YAG laser radiation, at 532 nm wavelength and 10 9 W/cm 2 intensity, is reported. Laser pulse generates a plasma at the target surface and produces high non-isotropic emission of neutral and ion species, which are mainly emitted along the normal to the target surface. Mass quadrupole spectrometry, associated to the electrostatic ion deflection, allows an estimation of the energy distributions and of the emitted charge states, within the plasma plume, as a function of the incident laser energy. Neutrals show typical Boltzmann distributions while ions show Coulomb-Boltzmann-shifted distributions. The plasma is characterized in terms of velocity, kinetic energy, ion charge state and temperature of the ejected particles. A special regard is given to the parameters which influence the plasma properties, such as the free electron density of the ablated elements. The ion acceleration processes occurring inside the plasma, due to the high electrical field generated in the charge non-equilibrium conditions, is also discussed. Introduction – Due to the multitude of photons and particles emission, laser-generated plasma can be characterized by different techniques, such as optical spectroscopy, mass spectrometry, Langmuir probe, charge collectors, etc. The laser pulse hits a solid target and produces, in vacuum, a fast mass sublimation with emission of a dense vapour, which expands at supersonic velocity along the normal to the irradiated target surface [1]. At high laser intensities, the vapour absorbs the laser photons increasing the plasma temperature, the ion energy and charge state. Plasma characterization, in terms of temperature, density, energy of ejected particles and charge state distribution, is of special interest in different fields (Microelectronics, Engineering, Bio-medicine, Nuclear physics, 34th EPS Conference on Plasma Phys. Warsaw, 2 - 6 July 2007 ECA Vol.31F, P-5.004 (2007)