Dottorato in FISICA DEGLI ACCELERATORI

Titolo della tesi: Single shot diagnostics for plasma accelerated beams

The next frontier of the particles accelerators requires more compactness and more affordable costs. Plasma-based accelerators overcome these issues thanks to their capability to reach high accelerating gradients using the high fields generated inside the plasma by a charge displacement induced by lasers or particle beams. This leads to a reduction of the accelerating structures. But all the machine must be reduced as well; in detail the diagnostics play a crucial role and such devices are required to be compact as much as possible. The first plasma accelerated beams are not stable as the ones from classic structures and hence there is the need to use diagnostics that allow a single shot characterization of the beam. The goal of this Ph.D. thesis work is the use of Optical Transition Radiation (OTR) to measure the transverse emittance in a single shot, with the simultaneous measurement of the beam spot, the beam divergence and the correlation term. The last two are computed from the OTR angular distribution; in particular for the correlation term, an innovative scheme with an array of micro-lenses is introduced and the relative studies are shown. This technique has tested at SPARC_LAB, the test facility for R&D for plasma acceleration and advanced photon sources at National Laboratory of Frascati. The setup and the experimental results are illustrated and discussed.