Tag Archives: Evento scientifico

R&D activity on Cu photo-cathodes is under development at the SPARC_LAB test facility to fully characterize each stage of the photocathode ‘‘life’’ and to have a complete overview of the photoemission properties in high brightness photo-injectors. The nano (n)-machining process presented here consists in diamond milling, and blowing with dry nitrogen. This procedure reduces the roughness of the cathode surface and prevents surface contamination introduced by other techniques, such as polishing with diamond paste or the machining with oil. Both high roughness and surface contamination cause an increase of intrinsic emittance and consequently a reduction of the overall electron beam brightness. To quantify these effects, we have characterized the photocathode surface in terms of roughness measurement, and morphology and chemical composition analysis by means of Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), and Atomic Force Microscopy (AFM) techniques. The effects of n-machining on the electron beam quality have been also investigated through emittance measurements before and after the surface processing technique. Finally, we present preliminary emittance studies of yttrium thin film on Cu photo-cathodes.

The design of specific fuel targets represents the crucial point of the Inertial Confinement Fusion scheme. In fact during the laser-matter interaction, due to the irradiation in homogeneities both parametric and hydrodynamic instabilities could be generated, leading to target pre-heating and compression inefficiency. In order to avoid these drawbacks it was considered of interest to coat fusion pellet with light foams, which can act as absorbers of the laser radiation, providing a more homogeneous irradiation and enhancing the efficiency of conversion of laser energy into shock wave energy [1,2]. The presentation will concern the results of 2016 experimental campaign, developed at ENEA research center in Frascati (Rome), in which we studied the behavior of a porous material (Polystyrene Foam) interacting with an high energy Nd laser pulse (duration 3 ns, 30J energy, focal spot dimension 100 µm). From streak camera images we estimated the volume involved in absorption and from the measurement of plasma expansion velocity it was possible to roughly estimate the plasma temperature. With semiconductor detectors we were able to get information about the X-ray emission. In particular we observed that porous materials present an X-ray emission higher than the respective solid material, being comparable to the amount emitted by an Aluminum target. Concerning the density profile, the interferometric images highlighted the presence of second harmonic emission, when irradiating solid material and its absence during the irradiation of porous plastic, which can be symptomatic of a plasma characterized by smoother density gradients [3]. References 1. R. De Angelis, …

The talk will tell about implementation of the theoretical concept for development of processes of radioactive waste water purification and bioremediation of radionuclide-contaminated environment using microorganisms and plants. The first part of the presentation will include analysis of selective accumulation of elements at organism and ecosystem levels in the context of Vernadsky biosphere theory as well as justification an idea that microorganisms are the most efficient bioaccumulating agents. Also, synergic effects of use of several types of organisms for radionuclide extraction will be considered. The second part will summarize concept outputs and discuss their application to overcome the key methodological problems of radioactive water purification. In this part detailed experimental results on microbial extraction of radionuclides from radioactive waste water will be given to demonstrate reliability and efficiency of established approach. The last part will summarize essential conditions for purification of liquid radioactive waste based on electrochemical approach and non-specific interaction (reduction and accumulation) of radionuclides with microorganisms. Finally, bioremediation strategies for radionuclide-contaminated environment and development of plant-microbial artificial ecosystems with the enhanced bioaccumulating capacity will be considered.

The proton is an essential constituent of the visible matter that surround and compose us, but some of its fundamental properties are still not understood. In this seminar, I will focus on Semi-Inclusive Deep Inelastic Scattering (SIDIS) of electrons on an unpolarized target as a way to get information on the proton three dimensional structure in momentum space. I will briefly introduce the theoretical framework that leads to the definition of the Transverse Momentum Partonic Distribution functions (TMDs). I will then consider the processes : ep → eπ±,0X, and ep → eK±X that are being measured at CLAS12 ( Jlab, USA) in a wide kinematic range and with high statistic. An overview of the detector will be given with particular emphasis to its particle identification capability, reached thanks to an innovative Ring Imaging Cherenkov detector realized by the INFN.

In the last two decades, the crucial role played by the high brightness electron beams in the frontier fields of radiation generation and advanced acceleration schemes has been largely established. The design and optimisation of high brightness RF linacs has shown to be essential for the coherent X-rays generation in the FELs as well for the realization of bright Inverse Scattering Compton (ICS) sources, depending the FELs on the electron beam peak brightness and the ICS sources on the electron beam maximum phase space density. These features for the electron beam are achieved thanks to a hybrid scheme consisting in an RF photo-injector followed by booster sections. At the INFN-LNF in Frascati both the ELI-NP Inverse Compton Scattering source, in its installation phase in Magurele (Romenia), and the EuPRAXIA@SPARC_LAB FEL facility are under study. The guidelines to design RF linac able to drive these sources and electron beam dynamics studies for these two machines are here presented.

The new Gamma Beam System (GBS) of the ELI-NP project, currently under installation in Magurele (RO) by INFN, as part of EuroGammaS consortium, can provide tunable gamma rays, with narrow bandwidth (0.3%) and a high spectral density (104 photons/sec/eV) by the Compton backscattering effect. A turn-key high level software has been designed to fully characterise the 6D beam phase space and the trajectory in order to help operator during commissioning with an easily scalable suite for any high brightness LINAC. Currently the high level software, interfaced with EPICS control system, manages automatically accelerator devices to allow electron beam diagnostic measurements (emittance, energy, spread, length, longitudinal profile). Next developments for preserving the beam quality of well-aligned bunch trains will include beam based alignment and dispersion free steering software.

                                                                                                                       Picture taken by Roy J. Glauber and published in nobel prize.org                                 This conference is organized in the framework of the John Templeton Foundation financed project: "Hunt for the "impossible atoms": the quest for a tiny violation of the Pauli Exclusion Principle. Implications for physics, cosmology and philosophy", being the concluding event, and is supported by the Museo Storico della Fisica e Centro Studi e Ricerche Enrico Fermi, Roma and by INFN. The main aim of the conference is to discuss the theoretical, philosophical and experimental aspects of the spin-statistics connection and its possible violation & related items (CPT and Lorentz symmetry violation; cosmological implications; identity versus indistinguishable etc.). Expert scientists and philosophers will give lectures on spin-statistics and spin-statistics violation  and on theories beyond the "standard" quantum mechanics, with an overview of hottest topics in these sectors.   Organizers: Catalina Curceanu, LNF-INFN (Chair) Johann Marton, SMI-Vienna (Austria) Edoardo Milotti, Univ. and INFN Trieste (Italy) Kristian Piscicchia, Museo Storico della Fisica e Centro Studi e Ricerche Enrico Fermi, Roma (Italy) Alessandro Scordo, LNF-INFN (Italy)    

The sub-GeV mass region of the dark matter is foreseeably to be explored intensively in the next generation of direct detection experiments. Essig and others recently discussed the feasibility of detecting the dark-matter electron recoil using low-noise semiconductor detectors as the active target. With a readout noise level below one electron RMS, the sensitivity allows us to test several theoretical models that account for dark matters with sub-GeV mass. One of the two silicon-based architectures that are capable of reaching such noise level is the DEPFET with Repetitive Non Destructive Readout (RNDR). The prototype of this detector has been developed by the Semiconductor Laboratory of the Max Planck Society, and the readout of a single pixel has successfully reached the expected sub-electron noise level . In this presentation, we will introduce the working concept of the DEPFET-RNDR. Then we will present the new project of DANAE under preparation that plans to apply this type of detector to the direct detection of dark-matter electron recoil.

Several aspects of flavour physics, including the recent experimental “anomalies” in leptonic decays, are critically reviewed. New ideas to improve the accuracy of the theoretical predictions and future developments are discussed.