R. Fiorito
A5079265337- Particle Accelerators and Free-Electron Lasers
- Particle accelerators and beam dynamics
- Laser-Plasma Interactions and Diagnostics
- Advanced X-ray Imaging Techniques
- Magnetic confinement fusion research
- Gyrotron and Vacuum Electronics Research
- Crystallography and Radiation Phenomena
- Ultrasonics and Acoustic Wave Propagation
- Pulsed Power Technology Applications
- Underwater Acoustics Research
- Acoustic Wave Phenomena Research
- Electron and X-Ray Spectroscopy Techniques
- Laser Design and Applications
- X-ray Spectroscopy and Fluorescence Analysis
- Particle Detector Development and Performance
- Photocathodes and Microchannel Plates
- Plasma Diagnostics and Applications
- Integrated Circuits and Semiconductor Failure Analysis
- Astrophysics and Cosmic Phenomena
- Astrophysical Phenomena and Observations
- Ionosphere and magnetosphere dynamics
- Quantum, superfluid, helium dynamics
- Superconducting Materials and Applications
- Gamma-ray bursts and supernovae
- Advanced Electron Microscopy Techniques and Applications
Cockcroft Institute
2010-2021
University of Liverpool
2010-2021
Campbell Collaboration
2020
Sci-Tech Daresbury
2017-2019
Google (United States)
2019
University of Maryland, College Park
2004-2016
European Organization for Nuclear Research
2016
United States Naval Research Laboratory
2012
Goddard Space Flight Center
2004-2006
Naval Surface Warfare Center
1990-2005
High energy particle accelerators have been crucial in providing a deeper understanding of fundamental particles and the forces that govern their interactions. In order to increase or reduce size accelerator, new acceleration schemes need be developed. Plasma wakefield acceleration, which electrons plasma are excited, leading strong electric fields, is one such promising novel technique. Pioneering experiments shown an intense laser pulse electron bunch traversing plasma, drives fields 10s...
Abstract This report presents the conceptual design of a new European research infrastructure EuPRAXIA. The concept has been established over last four years in unique collaboration 41 laboratories within Horizon 2020 study funded by Union. EuPRAXIA is first project that develops dedicated particle accelerator based on novel plasma acceleration concepts and laser technology. It focuses development electron accelerators underlying technologies, their user communities, exploitation existing...
The Advanced Proton Driven Plasma Wakefield Acceleration Experiment (AWAKE) aims at studying plasma wakefield generation and electron acceleration driven by proton bunches. It is a proof-of-principle R&D experiment CERN the world׳s first experiment. AWAKE will be installed in former CNGS facility uses 400 GeV/c beam bunches from SPS. experiments focus on self-modulation instability of long (rms ~12 cm) bunch plasma. These are planned for end 2016. Later, 2017/2018, low energy (~15 MeV)...
Sound transmission and reflection properties of an elastic layer immersed in a fluid are analyzed by extending the resonance formalism, previously developed us for case [J. Acoust. Soc. Am. 65, 9–14 (1979)]. Resonance expressions coefficients have been obtained both terms frequency-thickness variable angle-of-incidence variable. The positions widths explicitly from real equations given material quantities. Comparison theory exact calculations steel plate water. formalism results show...
We give direct experimental evidence for the observation of full transverse self-modulation a long, relativistic proton bunch propagating through dense plasma. The exits plasma with periodic density modulation resulting from radial wakefield effects. show that is seeded by ionization front created using an intense laser pulse copropagating bunch. extends over length following seed point. By varying one order magnitude, we frequency scales expected dependence on density, i.e., it equal to...
The Horizon 2020 Project EuPRAXIA ("European Plasma Research Accelerator with eXcellence In Applications") is preparing a conceptual design report of highly compact and cost-effective European facility multi-GeV electron beams using plasma as the acceleration medium. accelerator will be based on laser and/or beam driven approach used for photon science, high-energy physics (HEP) detector tests, other applications such X-ray sources medical imaging or material processing. started in November...
The seeded self-modulation of a relativistic, charged particle bunch in plasma is shown to grow both along the and plasma, resulting transverse wakefield amplitudes that far exceed initial seed values.
Recent studies have shown that strong correlations are observed between the low frequencies (1-10 Hz) of quasi-periodic oscillations (QPOs) and spectral power law index several black hole (BH) candidate sources, in (hard) states, steep (soft) transitions these states. The observations indicate X-ray spectra such state (phases) show presence a power-law component sometimes related to simultaneous radio emission, indicating probable jet. Strong QPOs (>20% rms) present density spectrum range...
AWAKE is a proton-driven plasma wakefield acceleration experiment. % We show that the experimental setup briefly described here ready for systematic study of seeded self-modulation 400\,GeV proton bunch in 10\,m-long rubidium with density adjustable from 1 to 10$\times10^{14}$\,cm$^{-3}$. short laser pulse used ionization vapor propagates all way along column, suggesting full vapor. occurs bunch, at time and follows affects bunch.
We discuss an experimental technique to visualize motion in the bulk of superfluid 4 He by tracking micron-sized solid hydrogen tracers. The behavior tracers is complex since they may be trapped quantized vortices while also interacting with normal fluid via Stokes drag. mechanism which as well dependencies on volume fraction, temperature, and flow properties. apply this study dynamics a thermal counterflow. Our observations serve direct confirmation two-fluid model quantitative test...
The study of modulated electron beams is important because they can be used to produce coherent radiation, but the modulations cause unwanted instabilities in some devices. Specifically, a free laser, proper prebunching at desired emission frequency enhance performance, while bunching resulting from and bunch compression schemes degrade performance. In photoinjector accelerator, tailoring shape drive laser pulse could as technique either or mitigate effect these modulations. This work...
We have developed several analytic and experimental techniques to measure the divergence emittance of charged particle beams, which employ optical transition radiation (OTR) produced from thin intercepting foils. OTR's directionality, promptness, linearity, polarization, sensitivity its angular distribution energy divergence, can be all exploited diagnose spatial distribution, energy, a beam. describe we separately determine x y emittances beam at an or waist using OTR single foil two...
We have observed up to 8 orders (n) in the spectra of parametric x-radiation (PXR) range 5--40 keV, produced by interaction a 90 MeV electron beam with mosaic graphite and single silicon crystals. The measured yields intensity ratios, I(n\ensuremath{\ge}2)/I(n=1), are not agreement theory PXR for In comparison, ratios intensities close predictions perfect bandwidths spectral lines both good theoretical predictions.
Spin-lattice and spin-spin relaxation time have been measured using the spin echo method in three hydrogen bonded liquids: glycerol, 1,3-butanediol, 2-methyl-2,4-pentanediol as a function of temperature through region T1 minimum at seven pressures range 0–3000 kg/cm2. The results this study lead to conclusion that translational model for NMR relaxational presented by Torrey is satisfactory representing diffusive motion molecules these viscoelastic liquids. Agreement between experimentally...
We use a relativistic ionization front to provide various initial transverse wakefield amplitudes for the self-modulation of long proton bunch in plasma. show experimentally that, with sufficient amplitude [$\ensuremath{\ge}(4.1\ifmmode\pm\else\textpm\fi{}0.4)\text{ }\text{ }\mathrm{MV}/\mathrm{m}$], phase modulation along is reproducible from event event, 3%--7% (of $2\ensuremath{\pi}$) rms variations all bunch. The not lower amplitudes. observe transition between these two regimes. Phase...
Ultraluminous X-ray sources (ULXs) with apparent luminosities up to hundreds of times the Eddington luminosity for a neutron star have been discovered in external galaxies. The existence intermediate-mass black holes has proposed explain these sources. We present evidence an hole ULX M82 X-1 based on spectral features and timing (quasi-periodic oscillation [QPO]) properties X-radiation from this source. revisited XMM-Newton Rossi X-Ray Timing Explorer (RXTE) data obtained 2001 1997 XMM RXTE,...
Transmission and reflection losses (TL, RL) are calculated as functions of frequency thickness (F×D) incidence angle (ϑ) for single multiple viscoelastic plates (steel, ABS, syntactic foam, neoprene, Plexiglas) using a transfer matrix method modified to include complex wave velocities. The calculation these velocities depends on four measurable material constants: longitudinal shear phase (cL, cs) absorption coefficients (αL, αS). A physical model is developed relate αL αS, shown be...
Beam halo is an important factor in any high intensity accelerator. It can cause difficulties the control of beam, emittance growth, particle loss, and even damage to therefore essential understand mechanisms formation its dynamics. Experimental measurement distribution a fundamental tool for such studies. In this paper, we present new dynamic range, adaptive masking method image beam halo, which uses digital micromirror-array device. This has been thoroughly tested laboratory using standard...
We have developed a novel method based on vector electromagnetic theory and Schelkunoff's principles, to calculate the spectral angular distributions of transition radiation (TR) diffraction (DR) produced by charged particle interacting with an arbitrary metallic target. The predicts polarization spectral-angular at distance from source, i.e., in both near far fields, any direction observation. fields TR DR calculated commonly used scalar Huygens model are shown be limiting forms those...
We give a short overview of the DarkLight detector concept which is designed to search for heavy photon A' with mass in range 10 MeV/c^2 < m(A') 90 and decays lepton pairs. describe intended operating environment, Jefferson Laboratory free electon laser, way extend DarkLight's reach using --> invisible decays.
We present a resonance theory for the acoustic transmission and reflection coefficients of an elastic plate imbedded in fluid medium, which includes effects viscosity. This formulation provides direct means determining material parameters from measured resonances Rayleigh Lamb waves (i.e., their positions frequency or angle, widths, heights) are given our formalism by explicit analytic expressions that depend on parameters. Viscosity is seen to manifest itself decrease peaks broadening...