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Carbon, titanium and silver nanoparticles have been added to biomedical grade Ultra High Molecular Weight Poly Ethylene (UHMWPE) for the creation of "white-white" joints welded with a diode laser operating at 970 nm wavelength. The physical and surface features of the nanocomposite sheets, before and after the laser welding process, were measured in terms of surface roughness and wet ability (of distilled water, Simulated Synovial Fluid and human blood). Their adhesion strength and effect of the different nanoparticles on the joint’s physical features have been evaluated by a lap shear test. Experimental results highlight as diode laser energy changes the surface features in a different way depending on filler’s thermal conductivity while bulk features seems to be mainly due to filler size and hence, their dispersion degree inside the polymeric matrix. [ABSTRACT FROM AUTHOR]

Selective deoxygenation of graphene oxide has been conducted with regard with the design and fabrication of graphene based devices. The ion beam lithography is considered to be a powerful method for patterning onto graphene oxide foil. A helium beam has been used for both direct patterning onto graphene oxide foil and simultaneous online characterisation of its structural and compositional changes. Scanning electron microscopy, energy dispersive spectroscopy and Rutherford backscattering spectrometry analyses have been accurately employed to reveal and monitor the deoxygenation of the graphene oxide foil demonstrating the reliability of the direct patterning using the ion beam lithography technique. [ABSTRACT FROM AUTHOR]

The maximum ion energy and acceleration efficiency have to be increased for practical applications of intense ion beams produced by intense short laser pulses incident on a thin foil. For this aim, we propose to use foil with a microscopic structure on the front size. We have prepared such targets by depositing a monolayer of polystyrene nanospheres of a size comparable to laser wavelength on a thin foil. The damage threshold of the produced targets is found experimentally above 3.5 x 109W/cm² for a nanosecond pedestal and above 1011 W/cm² for femtosecond prepulses. [ABSTRACT FROM AUTHOR]

The laser-generated plasma, in non equilibrium conditions, has peculiar properties depending strongly on the laser parameters, on the target composition and on the target geometry. Different fast diagnostic techniques can be employed for the plasma characterization in terms of particles and photons emission, plasma temperature and density, ion energy distribution, angular emission, yield and electric field acceleration. Particular attention is devoted to the proton emission from hydrogenated targets and to the proton diagnostics by using time of flight techniques and Thomson parabola spectrometry. The diagnostic techniques will be presented and discussed on the base of the development of the ELIMED project. [ABSTRACT FROM AUTHOR]

The development of implantation techniques requires investigation of laser plasma as a potential source of multiply charged ions. The laser ion source delivers ions with kinetic energy and a charge state dependent on the irradiated target material and the parameters of the laser radiation used. By the focusing the laser beam on the solid target the higher current densities of ions than by using other currently available ion sources can be produced. The crucial issue for efficiency of the ion implantation technology is selection of proper laser beam characteristics. Implantation of different kinds of laser-produced ions into metals and organic materials were performed recently at the PALS Research Center in Prague, in cooperative experiments using 0.4-ns iodine laser pulses having energies up to 750 J at wavelength of 1315 nm or up to 250 J at wavelength of 438 nm. In this contribution we describe the characterization and optimization of laser-produced Ge ion streams as well as analysis of the direct implantation of these ions into Si and SiO2 substrates. The Ge target was irradiated with the use of laser pulses of energy up to 50 J at radiation intensities of ∼1011 W/cm2 and ∼2′1013 W/cm2. The implanted samples were placed along the target normal at distances of 17, 31 and 83 cm from the target surface. The ion stream parameters were measured using the time-of-fight method. The depth of ion implantation was determined by the Rutherford backscattering method (RBS). The maximum depth of implantation of Ge ions was ∼450 nm. These investigations were carried out for optimization of low and medium energy laser-generated Ge ion streams, suitable for specific implantation technique, namely for fabrication of semiconductor nanostructures within the SRAP “SEMINANO” project. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

The ECLISSE experiment has been carried out by coupling a Laser Ion Source (based on a Nd:YAG laser (0.9 J / 9 ns, laser power densities <1011 W/cm2) to the SERSE superconducting ECR ion source. Cw beams of highly charged ions from metal samples without the use of ovens or sputtering technics were obtained in a variety of experimental conditions. The maximum charge states obtained from the ECRIS were 38+ for Ta and 41+ for Au. The peak current was obtained for 25+ and 29+ respectively and it was in the order of some tens of μA. In this work the analysis of some preliminary results obtained in afterglow mode will be also presented. We employed microwave pulse (length 4 msec) and laser pulse (length 9 nsec) with the same frequency (30 Hz) and variable relative phase. For appropriate phase values, a current enhancement of about one order of magnitude was observed. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

The SERSE source has been efficiently working at the Laboratori Nazionali del Sud in Catania since 1998, by operating at 14 and 18 GHz, with a maximum power of about 2 kW. The performance of the source has been optimised for the beam injection into the K-800 Superconducting Cyclotron, i.e. the maximisation of the charge states was looked for, provided that the current of the beam was about 0.5 to 5 eµA, which is the typical analysed current for routinely operations. In 2000 a collaboration was established in order to test the behavior of SERSE at 28 GHz, so that a new operating domain could be studied, featuring a very dense plasma (up to 10[sup 13] cm[sup -3]) and a very high ion current (1 emA of Pb[sup 27+] is the goal of CERN and GSI for future heavy ion projects and 0.5 cma was considered to be a challenge for our experiment). Tests were carded out with a generator based on a gyrotron tube which was refurbished and made available by CEA; Xenon ions were chosen as a reference being the ionisation difficulty for Xe[sup 20+] similar to the one of P[sup 27+]. The results were excellent and the current of Xe[sup 20+] exceeded our expectations (more than 0.5 emA in afterglow and about 0.3 cma in dc mode). These results, obtained with a power limited to 4 kW in dc mode and 6.5 kW in pulsed mode because of the poor chamber cooling, can be considered as a remarkable step, in view of the third generation of electron cyclotron resonance ion source (ECRIS). The details of the experiments will be described, along with the design of the next superconducting ECRIS, the GyroSERSE source, which is expected to produce beam currents above 1 mA for intermediate charge states as well as very high charge states, 50[sup +] to 60[sup +] for the heaviest ions, with currents above 1 eµA. [ABSTRACT FROM AUTHOR]