Mass quadrupole spectrometry applied to laser-produced plasmas and microwave ignited plasmas

The mass quadrupole spectrometry (MQS) permits the characteization of non-equilibrium and equilibrium plasmas obtained by means of laser ablation and microwave ionization. A Nd:YAG laser, 150 mJ pulse energy, 3 ns pulse duration, operating at 1064 nm fundamental and 532 nm second harmonic wavelength, at intensities of the order of 10^10 W/cm^2, in single pulse or at a repetition rate between 1 and 10 Hz, interacting with solid targets placed in high vacuum produces ablation with plasma formation. It is possible to analyze the ion and the neutral emission from plasma in the mass range 1-300 amu with a mass resolution better than I amu and a sensitivity of the order of 1 p.p.m.. Moreover, it is possible to select the ion energy in the range 1 eV - 1 KeV with an electric deflection filter. MQS allows to measure the temperature and density of the plasma, the relative ion and neutral amounts, the fractional ionization of the plasma, the elements and chemical compounds of the species participant to the plasma formation, the ion charge state, the ion energy distributions and the angular dishibution of the emitted ions. Operating in repetition rate it measures the depth profile of peculiar elements in the ablated targets. Moreover, MQS permits also to characteize microwave ignited plasmas, obtained by means of microwaves at two different frequencies, 2.45 GHz (Magnetron) and 3.7478 GHz (TWT), axially launched inside the plasma chamber, where a shongly non uniform magnetostatic field exists (with a maximum value of 0.1 T), with two possible configurations depending on the used ion source (plasma Reactor or VIS). In the regions under ECR (Electron Cyclotron Resonance) the X-B conversion is possible, the incoming electromagnetic extraordinary mode X is converted into a Bernstein wave B, i.e. an electrostatic wave which can propagate in an overdense plasma. Plasma density and temperature measurements, obtained with a Langmuir Probe and X-ray detectors, confirmed successfully the mode conversion and the formation of an overdense plasma. The similarities with non-equilibrium plasmas generated by laser ablation will be described alone with the differences.