Sistemi X-Ray-EUV laser plasma: messa a punto caratterizzazione e applicazioni per lo studio in vivo di campioni biologici

The work presented in this thesis was mainly developed at the Quantum Electronics and Plasma Laboratory (QEPL) of the University of Rome Tor Vergata. Since manu years at QEPL an activity devoted to the development of power laser systems was started to product Soft X rays via the interaction between solid target and laser radiation. In this work I shall present the above mentioned apparatus, together with its improvement and characterization to reach the goal of producing radiation within Extreme Ultraviolet (EUV) region, thanks to the use of a supersonic gas jet target of Xenon. At the same time I shall illustrate a new technique to record images of biological samples, based on an innovative detector device: the LiF crystals. The utilization of these devices, together with th radiation delivered by our laser plasma source, allow relevant appplications in microscopy analysis since they permit to obtain images of flash of life of the tested biological sample. The subsequent study of the images revealed that LiF crystals exhibit a high intrinsic resolution, with a dynamical response much higher than that reached with PMMA films. Unfortunately there is still an open problem: the spatial resolution obtainable by the optical apparatus which reads the LiF sample. Up to now the best values are of the order of 500nm. I shall futhermore show the experimental results obtained by means of a CCD camera with which microradiographies of dewatered biological samples treated by heavy metals were acquired. In this case different absorption of X rays radiation have been measured, to perform studies of bioaccumulation. Finally, the end of this thesis will be devoted to the description of the state of the art of another laser system based on a femtosecond Ti:Sa oscillator. I shall describe the performances of the first amplifier and compressor, which was installed. This apparatus will be utilized to inject an ultra short pulse into an Excimer KrFl laser, last amplification stage of the whole chain, to produce ultra short pulse trains in the UV region.