A5049403284- Laser-Plasma Interactions and Diagnostics
- Laser-Matter Interactions and Applications
- Laser-induced spectroscopy and plasma
- Particle Accelerators and Free-Electron Lasers
- Advanced X-ray Imaging Techniques
- Laser Design and Applications
- Particle accelerators and beam dynamics
- Magnetic confinement fusion research
- High-pressure geophysics and materials
- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Plasma Diagnostics and Applications
- Atomic and Molecular Physics
- Particle Detector Development and Performance
- Solid State Laser Technologies
- Nuclear Physics and Applications
- Radiation Therapy and Dosimetry
- Advanced X-ray and CT Imaging
- Advanced Fiber Laser Technologies
- Nonlinear Optical Materials Research
- Particle physics theoretical and experimental studies
- Crystallography and molecular interactions
- Solar and Space Plasma Dynamics
- Ionosphere and magnetosphere dynamics
- Laser Material Processing Techniques
Imperial College London
2014-2024
University of Lisbon
2014-2024
John Adams Institute for Accelerator Science
2014-2024
Plasma (Russia)
2002-2024
Campbell Collaboration
2020-2023
Instituto Superior Técnico
2008-2021
Rutherford Appleton Laboratory
2021
Instituto Politécnico de Lisboa
2003-2020
Lancaster University
2019
University of Strathclyde
2019
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...
Metal foil targets were irradiated with 1 mum wavelength (lambda) laser pulses of 5 ps duration and focused intensities (I) up to 4x10;{19} W cm;{-2}, giving values both Ilambda;{2} pulse comparable those required for fast ignition inertial fusion. The divergence the electrons accelerated into target was determined from spatially resolved measurements x-ray K_{alpha} emission transverse probing plasma formed on back foils. Comparison other published data shows that it increases is...
Abstract A bright μm-sized source of hard synchrotron x-rays (critical energy E crit > 30 keV) based on the betatron oscillations laser wakefield accelerated electrons has been developed. The potential this for medical imaging was demonstrated by performing micro-computed tomography a human femoral trabecular bone sample, allowing full 3D reconstruction to resolution below 50 μm. use 1 cm long accelerator means that length beamline (excluding laser) is dominated x-ray distances rather...
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)...
Experiments were performed to investigate the propagation of a high intensity (I approximately 10(21) W cm(-2)) laser in foam targets with densities ranging from 0.9n(c) 30n(c). Proton acceleration was used diagnose interaction. An improvement proton beam energy and efficiency is observed for lowest density (n(e)=0.9n(c)), compared higher foams. Simulations show that penetrates deeper into target due its relativistic results greater collimation ensuing hot electrons. This rear surface...
New acceleration technology is mandatory for the future elucidation of fundamental particles and their interactions. A promising approach to exploit properties plasmas. Past research has focused on creating large-amplitude plasma waves by injecting an intense laser pulse or electron bunch into plasma. However, maximum energy gain electrons accelerated in a single stage limited driver. Proton bunches are most drivers wakefields accelerate TeV scale stage. An experimental program at CERN—the...
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 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.
Significance High-resolution microcomputed tomography with benchtop X-ray sources requires long scan times because of the heat load limitation on anode. We present an alternative, high-brightness plasma-based source that does not suffer from this restriction. A demonstration a centimeter-scale complex organism achieves equivalent quality to commercial scanner. will soon be able record such scans in minutes, rather than hours required by conventional tubes.
Betatron radiation from laser wakefield accelerators is an ultrashort pulsed source of hard, synchrotron-like x-ray radiation. It emanates a centimetre scale plasma accelerator producing GeV level electron beams. In recent years betatron has been developed as unique capable high resolution images in compact geometries. However, until now, the short pulse nature this not exploited. This report details first experiment to utilize image rapidly evolving phenomenon by using it radiograph driven...
Laser-wakefield accelerators (LWFAs) are high acceleration-gradient plasma-based particle capable of producing ultra-relativistic electron beams. Within the strong focusing fields wakefield, accelerated electrons undergo betatron oscillations, emitting a bright pulse X-rays with micrometer-scale source size that may be used for imaging applications. Non-destructive X-ray phase contrast and tomography heterogeneous materials can provide insight into their processing, structure, performance....
We show in experiments that a long, underdense, relativistic proton bunch propagating plasma undergoes the oblique instability, which we observe as filamentation. determine threshold value for ratio between transverse size and skin depth instability to occur. At threshold, outcome of experiment alternates filamentation self-modulation (evidenced by longitudinal modulation into microbunches). Time-resolved images density distribution reveal grows an observable level late along bunch,...
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.
Plasma wakefield acceleration is a promising technology to reduce the size of particle accelerators. The use high energy protons drive wakefields in plasma has been demonstrated during Run 1 AWAKE programme at CERN. Protons 400 GeV drove that accelerated electrons 2 under 10 m plasma. collaboration now embarking on with main aims demonstrate stable accelerating gradients 0.5–1 GV/m, preserve emittance electron bunches and develop sources scalable 100s metres beyond. By end 2, scheme should...
Experimental results show that hosing of a long particle bunch in plasma can be induced by wakefields driven short, misaligned preceding bunch. Hosing develops the plane misalignment, self-modulation perpendicular plane, at frequencies close to electron frequency, and are reproducible. Development depends on misalignment direction, its growth extent proton charge. Results have main characteristics theoretical model, relevant other plasma-based accelerators represent first characterization...
Experiments were performed on laser wakefield acceleration in the highly nonlinear regime. With powers P<250 TW and using an initial spot size larger than matched for guiding, we able to accelerate electrons energies E_{max}>2.5 GeV, fields exceeding 500 GV m^{-1}, with more 80 pC of charge at E>1 GeV. Three-dimensional particle-in-cell simulations show that oversized delays injection, avoiding beam loss as undergoes length oscillation. This enables injected remain regions highest...
The frequency up-shifts of ultrashort laser pulses (65 fs) propagating in opposite directions (20\ifmmode^\circ\else\textdegree\fi{} and 160\ifmmode^\circ\else\textdegree\fi{}) with respect to a relativistic ionization front (interface gas plasma) are measured for the first time. Up-shifts order 25 nm observed. A very good agreement is found two-dimensional ray-tracing theory.
A “table-top” high power laser has been used to generate beams of accelerated electrons up energy 20 MeV from interactions with underdense plasmas. The spectrum these was measured using a magnetic spectrometer and proof-of-principle experiments were performed evaluate the suitability for electron radiography applications.
Single-shot absorption measurements have been performed using the multi-keV X-rays generated by a laser wakefield accelerator. A 200 TW was used to drive accelerator in mode which produced broadband electron beams with maximum energy above 1 GeV and broad divergence of $\approx15$ miliradians FWHM. Betatron oscillations these electrons $1.2\pm0.2\times10^6$ photons/eV 5 keV region, signal-to-noise ratio approximately 300:1. This sufficient allow high-resolution XANES at K-edge titanium...
The expansion of electromagnetic postsolitons emerging from the interaction a 30 ps, $3\ifmmode\times\else\texttimes\fi{}{10}^{18}\text{ }\text{ }\mathrm{W}\text{ }{\mathrm{cm}}^{\ensuremath{-}2}$ laser pulse with an underdense deuterium plasma has been observed up to 100 ps after propagation, when large numbers were seen remain in plasma. temporal evolution accurately characterized high spatial and resolution. is compared analytical models three-dimensional particle-in-cell results,...
Advances in X-ray imaging techniques have been driven by advances novel sources. The latest fourth-generation sources can boast large photon fluxes at unprecedented brightness. However, the size of these facilities means that are not available for everyday applications. With laser plasma acceleration, electron beams now be generated energies comparable to those used light sources, but university-sized laboratories. By making use strong transverse focusing accelerators, bright betatron...