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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.

New photo-injector sources having fast response time, long lifetime and relatively high-quantum efficiency (QE) are very needed for many applications. Metallic cathodes are promising candidates to supply high-intensity and good quality electron beams. We carried out measurements utilising thin films and a smooth bulk made of yttrium (Y). The Y thin films were produced by pulsed laser deposition (PLD, using a XeCl excimer laser) in high vacuum. It was covered, in situ, by a gold film to avoid oxidation. The Y smooth bulk was mechanically processed in air. The laser used to get experimental values of photoemission was a KrF excimer laser of 5 eV photon energy and 23 ns pulse duration. The maximum accelerating voltage applied to the photodiode (the anode) was+25 kV. The measurements of photocurrent were performed at different laser energies. We found that the output current was depended on the cathode surface. The higher QE values were obtained for the smooth cathode. It provided a maximum output current of 8.4 A, at 25 kV and 12 mJ laser energy. The maximum QE was 7.0x(10)^-5.

In this work, the photoemission performance of rough and smooth cathodes is presented. The cathodes were made up of pure yttrium metal bulk. For evaluation of the photocathodes, a KrF excimer laser, operating at 248 nm wavelength, 5 eV photon energy and 23 ns full width at half maximum (FWHM) was used. The targets were tested in a vacuum photodiode cell at 10^(-7) mbar; they were irradiated at normal incidence and the anode-cathode distance was set to 5 mm. The measurements were performed after a series of electric breakdowns between anode and cathode, induced under high laser energy and high accelerating voltage. This operation was performed in order to restore/increase the surface roughness. For the rough cathode, the maximum output current was 10.5 A, reached at 25 kV and 12 mJ laser energy; the maximum quantum efficiency (QE) value was 1.3 x 10^(-4), whereas for the smooth cathode, the maximum output current was 8.4 A and the maximum QE value was 7.0 x 10^(-5), calculated in the same experimental conditions. The temporal behavior of photoemission from these cathodes was studied. Plasma production and Schottky effect played a fundamental role in this process.

In this work we present the experimental study and a theoretical approach of the photoemission of rough and smooth photocathodes. The cathode bulk was made of pure yttrium while its surface was morphologically modified. The cathode surface was irradiated by a KrF excimer at normal incidence with the anode-cathode distance set to 5mm. The measurements were performed after electric breakdowns between anode and cathode, induced under high laser energy and high accelerating voltage. This operation was made in order to increase the surface roughness. For the rough cathode the maximum output current was 10.5 A, reached at 25 kV and 12 mJ, with a maximum quantum efficiency value of 1.3×10-4. Instead, under the same experimental conditions the smooth cathode provided an output current of 8.4 A with a maximum quantum efficiency value of 7.0×10-5. We can conclude that in this process the plasma production and the Schottky effect play a fundamental role.

In this work, we present a new pulsed laser ablation technique to obtain energetic ion beams. The accelerator we made is a compact device able to extract and accelerate the ionic components of plasma up to 160 keV per charge state. It is composed by a generating chamber containing an expansion chamber used like first electrode. Next, a second electrode connected to ground and a third electrode connected to negative voltage are used. The third electrode is used also as Faraday cup. By the analysis of the ion signals we studied the plume parameters such as TOF accelerated signals, charge state, and divergence.