Low emittance ion beams by laser interaction

Laser ion sources offer the possibility to get ion beam utilizable to improve particle accelerators. Today many laboratories, as well as the LEAS, are employed to develop accelerators of the dimensions very contained to be installed in little laboratories and hospitals. Pulsed lasers at intensities of the order of 108 W/cm2 and of ns pulse duration interacting with solid matter in vacuum, plasma of high temperature and density is produced. The charge state distribution of the plasma generates high electric fields which accelerate ions along the normal to the target surface. The energy of emitted ions has a Maxwell Boltzmann distribution which depends on the ion charge state. To increase the ion energy, a post-acceleration system can be employed by means of high voltage power supplies of about 100 kV. The post acceleration system results a good method to obtain high ion currents by a not expensive system and the final ion beams find interesting applications in the field of the ion implantations, adrotherapy, scientific applications and industrial use. In this work we compare the electromagnetic and geometric properties, like the emittanza, of the beams delivered by a Cu and Y target. The characterization of the plasma was performed by a Faraday cup for the electromagnetic characteristics, whereas a pepper pot system for the geometrical ones. At 60 kV accelerating voltage and 5.5 mA output current the normalized beam emittance resulted of 0.22 π mm mrad for the Cu target, while under the same accelerating voltage but with 7.4 mA output current a lower normalized beam emittance value was reached for the Y target. It resulted of 0.14 π mm mrad. The brightness of the beams was of 114 and 378 mA( mm mrad)-2 for the Cu and Y target, respectively. When Ag targets were utilised, we implanted an AISI 420 stainless steel by a dose of 10x1015 inos/cm2. Besides, the laser ion sources have got very good properties to feed large machines.