1

A Microwave Discharge Plasma Reactor devoted to the complex molecules dissociation has been designed and assembled at INFN-LNS in Catania. It operates with microwaves at 2.45 GHz triggering an off-resonance discharge in presence of a magnetic field provided by a Nd-Fe-B permanent magnet. A systematic characterization of the plasma properties (electron temperature and density, ion density, ecc.) by means of a Langmuir Probe has shown that the plasma distribution becomes strongly non-homogeneous for low pressures (below 0.3 mbar) and high power (above 70 W), as an overdense plasma is created in proximity of the microwave window [1]. Here a complete series of measurements about the power absorbed and reflected from the plasma is presented. The measurements have been carried out also during the plasma evolution towards the strongly non-homogeneous and overdense state, along with measurements of plasma physical characteristics by means of a Langmuir Probe. 1