Laser ion source for multiple Ta ion implantation

A laser ion source (LIS) is employed to produce a non-equilibrium tantalum plasma and to accelerate and focalise ejected ions towards an aluminium substrate. The new ion source is obtained with a pulsed Nd:Yag laser operating at 10(10) W/cm(2) and 30 Hz repetition rate. The plasma contains ions at high energy (1-8 keV) and high charge state (up to 8(+)) and a fractional ionisation of about 10%. The plasma density is of the order of 10(18)/cm(3) and the maximum ion temperature of the plasma core is of the order of 300 eV. The maximum extracted ion current is about I mA. Ejected ions have a narrow angular aperture along the normal to the target surface; they can be focalised by magnetic and electrical fields and accelerated by electrical fields. 40 kV potential is employed to accelerate the ions (from 40 keV up to 320 keV) and to produce multiple ion implantation on aluminium substrates. Experimental results and simulation calculations are presented about the effects of the multiple ion implantation in the aluminium substrates. The implants, concerning ion energies of the order of hundreds of eV, can be employed in metallurgical field to improve the chemical and physical properties of the surfaces of the implanted materials.