Ricerc@Sapienza

Starting from the electric fields produced by a point charge and a dipole traveling inside a circular vacuum chamber, in this paper we derive a formalism for a complete set of equations that describe the electromagnetic fields and the longitudinal and transverse coupling impedances arising by the interaction of a beam with a perfectly conducting pipe in the case of elliptic geometry.

The CERN Proton Synchrotron (PS) routinely crosses transition energy at around 6 GeV in order to accelerate protons that are injected in the Super Proton Synchrotron (SPS) or transferred to users of fixed target experiments. Depending on the beam parameters and intensity, a fast vertical coherent instability occurs during transition crossing.

We have investigated the formation, evolution, and late-time propagation of a laser-generated cylindrical blast wave (BW). The whole blast wave evolution over timescales of several nanoseconds was reconstructed experimentally (via temporally resolved interferometric measurements) and via hydrodynamic simulations that included modeling of nonlocal electron transport and radiation diffusion.

Localized strained silicon was observed with a suitable resolution in a real semiconductor device
by tip-enhanced Raman spectroscopy (TERS). The device was made via a standard industrial process
and its silicon trench isolation structures were used for the silicon strain analysis obtaining
results according to finite element method-based simulation data. We have achieved a reliable and
repeatable enhancement factor obtaining a trace of strained silicon along the structure with suitable

An innovative, single-shot, non-intercepting monitor of the transverse profile of plasma-accelerated electron beams is presented, based on the simultaneous measurement of the electron energy and the betatron radiation spectra. The spatial resolution is shown to be down to few tens of nanometers, important for high-precision applications requiring fine shaping of beams and detailed characterizations of the electron transverse phase space at the exit of plasma accelerating structures.

We report on the experimental characterization of the effect that a passive plasma lens in the overdense regime has on high-brightness bunch quality by means of 6D phase-space analysis. The passive lens is generated by confining hydrogen gas with a capillary tube pre-ionized with a high-voltage discharge. We observed that the optimum condition is retrieved at the end of the overdense regime with almost no effect on bunch brightness.

The active plasma lens represents a compact and affordable tool with radially symmetric focusing and field gradients up to several kT/m. In order to be used as a focusing device, its effects on the particle beam distribution must be well characterized. Here, we present the experimental results obtained by focusing an high-brightness electron beam by means of a 3 cm-long discharge-capillary pre-filled with Hydrogen gas. We achieved minimum spot sizes of 24lm (rms) showing that, during plasma lensing, the beam emittance increases due to nonlinearities in the focusing field.