A MAGNETRON SYSTEM FOR HIGH-FLUX PLASMA-SURFACE INTERACTION EXPERIMENTS

A new compact magnetron plasma system and its characteristics are desc ribed. The system makes it possible to carry out ion irradiation exper iments at high fluxes of 10(18) ions/cm(2).s and to reach fluences of 10(22) cm(-2), with a homogeneous distribution over an area of 0.3 x 0 .2 cm(2). The sample temperature, the distribution of ion flux densiti es within the sputtering zone, and the energy spectrum of ions are in situ measured during irradiation. The device is capable of producing a discharge current of up to 1.2 A and mean current densities of up to 100 mA/cm(2). The mean ion energy can be regulated in the range 50-500 eV by changing the working pressure and the discharge self-sustaining degree. The plasma can be swept over the interaction zone by using a moving magnet controlled by a stepping motor. The VC characteristics a nd discharge current relations were measured for several different gas es and at different pressures in the plasma. integral ion energy and c urrent density distributions at the cathode surface were measured at d ifferent parameters. In the first experiments targets of graphite, sil icon, molybdenum and titanium were used and exposed under similar plas ma conditions using deuterium in the discharge, energies of 150 eV and fluences of 10(21) cm(-2). RES (Rutherford backscattering spectrometr y) and NRA (Nuclear reaction analysis) were analytical techniques for the determination of deposited layers with respect to the quantity of deposits and for the study of the purity and homogeneity of the irradi ated layers.