A5041887680- Laser-Plasma Interactions and Diagnostics
- Advanced X-ray Imaging Techniques
- Laser-induced spectroscopy and plasma
- High-pressure geophysics and materials
- Laser-Matter Interactions and Applications
- Nuclear Physics and Applications
- Particle accelerators and beam dynamics
- Particle Accelerators and Free-Electron Lasers
- American Environmental and Regional History
- Laser Design and Applications
- Museums and Cultural Heritage
- Advanced X-ray and CT Imaging
- 3D Surveying and Cultural Heritage
- Economic and Environmental Valuation
- Physics of Superconductivity and Magnetism
- Molecular Junctions and Nanostructures
- Laser Material Processing Techniques
- Manufacturing Process and Optimization
- Legal Systems and Judicial Processes
- Environmental Conservation and Management
- Wildlife Conservation and Criminology Analyses
- Ion-surface interactions and analysis
- Property Rights and Legal Doctrine
- Quantum-Dot Cellular Automata
- Radiation Therapy and Dosimetry
Imperial College London
2014-2024
Deutsches Elektronen-Synchrotron DESY
2021-2024
John Adams Institute for Accelerator Science
2017-2024
University College London
2022
University of Strathclyde
2022
Cockcroft Institute
2022
Universität Hamburg
2022
Prairie Education and Research Cooperative
2014-2021
University of York
2020
University of Oxford
2017-2019
The dynamics of energetic particles in strong electromagnetic fields can be heavily influenced by the energy loss arising from emission radiation during acceleration, known as reaction. When interacting with a high-energy electron beam, today's lasers are sufficiently intense to explore transition between classical and quantum reaction regimes. We present evidence collision an ultrarelativistic beam generated laser-wakefield acceleration (ϵ>500 MeV) laser pulse (a0>10). measure postcollision...
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...
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....
Energy-efficient plasma-wakefield acceleration of particle bunches with low energy spread is a promising path to realizing compact free-electron lasers and colliders. High efficiency can be achieved simultaneously by strong beam loading plasma wakefields when accelerating carefully tailored current profiles [M. Tzoufras et al., Phys. Rev. Lett. 101, 145002 (2008)]. We experimentally demonstrate such optimal in nonlinear electron-driven accelerator. Bunches an initial 1 GeV were accelerated...
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 HALHF collaboration has discussed a new baseline for the project, taking into account comments from accelerator community on various aspects of original design. In particular, these concerned practicality dual-purpose linac to accelerate both colliding positron bunches and drive beams required plasma linac. addition, many other project were also considered; discussion conclusions are documented in this paper. Finally, is outlined that been optimised addresses several weaknesses design,...
The direction of the easy axis magnetization in ${\ensuremath{\gamma}}^{\ensuremath{'}}$ -${\mathrm{Fe}}_{4}$N has been determined by detailed analysis certain peaks M\"ossbauer spectrum a powdered sample an applied magnetic field. indicates magnetic-easy-axis to be along $〈100〉$. electric field gradient at face-centered Fe atoms is calculated - 7.0\ifmmode\times\else\texttimes\fi{}${10}^{14}$ esu/${\mathrm{cm}}^{3}$.
We present a design for pixelated scintillator based gamma-ray spectrometer non-linear inverse Compton scattering experiments. By colliding laser wakefield accelerated electron beam with tightly focused, intense pulse, photons up to 100 MeV energies and few femtosecond duration may be produced. To measure the energy spectrum angular distribution, 33 × 47 array of cesium-iodide crystals was oriented such that crystal length axis parallel in vertical direction. Using an iterative deconvolution...
Fundus autofluorescence (AF) arises from lipofuscin, which is derived retinoid byproducts of the visual cycle and accumulates within retinal pigment epithelial cells. Alterations in AF pattern are seen a wide range degenerations. Choroideremia an X-linked dystrophy caused by loss-of-function mutations CHM gene, encoding Rab escort protein-1.1van den Hurk J.A. Schwartz M. van Bokhoven H. et al.Molecular basis choroideremia (CHM): involving protein-1 (REP-1) gene.Hum Mutat. 1997; 9:...
For plasma-wakefield accelerators to fulfill their potential for cost effectiveness, it is essential that energy-transfer efficiency be maximized. A key aspect of this the near-complete transfer energy, or depletion, from driver electrons plasma wake. Achieving full depletion limited by process re-acceleration, which occurs when decelerate nonrelativistic energies, slipping backward into accelerating phase wakefield and being subsequently re-accelerated. Such re-acceleration unambiguously...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTInfrared Spectra of FulvenesJ. C. Wood, R. M. Elofson, and D. SaundersCite this: Anal. Chem. 1958, 30, 8, 1339–1342Publication Date (Print):August 1, 1958Publication History Published online1 May 2002Published inissue 1 August 1958https://pubs.acs.org/doi/10.1021/ac60140a013https://doi.org/10.1021/ac60140a013research-articleACS PublicationsRequest reuse permissionsArticle Views147Altmetric-Citations27LEARN ABOUT THESE METRICSArticle Views are the...
X-rays generated by betatron oscillations of electrons in a laser-driven plasma accelerator were characterised and applied to imaging industrial samples. With 125 TW laser, low divergence beam with 5.2±1.7 × 107 photons mrad−2 per pulse was produced synchrotron spectrum critical energy 14.6±1.3 keV. Radiographs obtained metrology test sample, battery electrodes, damage site composite material. These results demonstrate the suitability source for non-destructive evaluation applications. The...
Laser-plasma acceleration (LPA) is a compact technique to accelerate electron bunches highly relativistic energies, making it promising candidate power radiation sources for industrial or medical applications. We report on the generation of beams from an 80 MeV-level LPA setup based ionization injection (II) over duration 8 hours at repetition rate 2.5 Hz, resulting in 72,000 consecutive shots with charge and acceleration. Over full operation time moving averages total beam 14.5 pC between...
We report on a novel, noninvasive method applying Thomson scattering to measure the evolution of electron beam energy inside laser-plasma accelerator with high spatial resolution. The determination local enabled in-situ detection acting acceleration fields without altering final state. In this Letter we demonstrate that accelerating evolve from (265±119) GV/m (9±4) in plasma density ramp. presented data show excellent agreement particle-in-cell simulations. This provides new possibilities...
Highly collimated betatron radiation from a laser wakefield accelerator is promising tool for spectroscopic measurements. Therefore there requirement to create spectrometers suited the unique properties of such source. We demonstrate spectrometer which achieves an energy resolution < 5 eV at 9 keV and angularly resolving x-ray emission allowing reference spectrum be recorded same time. The single photon analysis used significantly reduce background noise. Theoretical performance various...
We report on the evaluation of performance self-guiding over extended distances with and focussing geometries. Guiding or more than 100 Rayleigh ranges was observed optic at . Analysis guiding found that extent exiting laser spatial mode closely followed matched spot size predicted by 3D nonlinear theory. Self-guiding an also characterised, guided modes for a plasma length density This corresponds to self-guided propagation 53 is similar obtained discharge channel guiding.
In conventional viologen-based electrochromic displays, contrast changes are achieved by modulating light using the optical absorbance of electrodeposited film. A display technique is described which uses instead scattering properties same film to produce intensity variations. Under practical conditions, ratios 60:1 can be electrodepositing 1 mC cm−2 n-heptyl viologen cation radical with a 1-ms current pulse. The also has memory and compatible integrated drive schemes.
A laser-wakefield driven x-ray source is used for the radiography of human bone. The betatron motion accelerated electrons generates x-rays which are hard (critical energy keV), have small size (<3 μm) and high average brightness. generated from a helium gas cell near-instantly replenishable, thus photon flux limited by repetition rate driving laser rather than breakdown source. tomograph bone sample was recorded with resolution down to 50 μm. sufficiently that radiograph could be taken each...
X-ray backscatter imaging can be used for a wide range of applications, in particular industrial inspection and portal security.Currently, the application this technique to detection landmines is limited due surrounding sand or soil strongly attenuating 10s 100s keV X-rays required imaging.Here, we introduce new approach involving 140 MeV short-pulse (< 100 fs) electron beam generated by laser wakefield acceleration probe sample, which produces Bremsstrahlung within sample enabling greater...