Ion acceleration by a double stage accelerating device for laser-induced plasma ions

A new LIS configuration was studied and realized in order to generate and accelerate ions of different elements. This ion source consisted of a laser-induced plasma from solid targets where the plume was made to expand before the action of the accelerating field. The accelerating field was reached by the application of two high voltage power supplies of different polarity. Therefore, the ions were undergone to double acceleration which can imprint a maximum ion energy up to 160keV per charge state. We analyzed the extracted charge from a Cu target as a function of the accelerating voltage at the laser fluence of 1.7 and 2.3 J/cm^2. At 60kV of total accelerating voltage and higher laser fluence, the maximum ion dose was of 10^12 ions/cm^2. Under this last conditions the maximum output current was 5 mA and the emittance measured by pepper pot method resulted of 0.22 π mm mrad. By this machine biomedical materials as UHMWPE were implanted with carbon and titanium ions. At doses of 6x10^15 ions/cm^2 the polyethylene surface increased its micro hardness of about 3-hold measured by the scratch test.