A5065782742- Laser-Plasma Interactions and Diagnostics
- Laser-induced spectroscopy and plasma
- Laser-Matter Interactions and Applications
- Particle Accelerators and Free-Electron Lasers
- Laser Design and Applications
- Particle accelerators and beam dynamics
- Magnetic confinement fusion research
- Gyrotron and Vacuum Electronics Research
- Plasma Diagnostics and Applications
- Pulsed Power Technology Applications
- High-pressure geophysics and materials
- Atomic and Molecular Physics
- Advanced X-ray Imaging Techniques
- Advanced Surface Polishing Techniques
- Nuclear Physics and Applications
- Advanced Fiber Laser Technologies
- Particle Detector Development and Performance
- Diamond and Carbon-based Materials Research
- Terahertz technology and applications
- Ion-surface interactions and analysis
- Planetary Science and Exploration
- Advanced Optical Sensing Technologies
- Laser Material Processing Techniques
- Electron and X-Ray Spectroscopy Techniques
- Muon and positron interactions and applications
University of California, Berkeley
2015-2025
Lawrence Berkeley National Laboratory
2016-2025
University of California System
2007-2024
University of Michigan–Ann Arbor
2012-2023
Hamburg Institut (Germany)
2022
Universität Hamburg
2022
Deutsches Elektronen-Synchrotron DESY
2022
National Institutes for Quantum Science and Technology
2021
Czech Academy of Sciences, Institute of Physics
2021
Keldysh Institute of Applied Mathematics
2021
Laser-driven plasma-based accelerators, which are capable of supporting fields in excess $100\phantom{\rule{0.3em}{0ex}}\mathrm{GV}∕\mathrm{m}$, reviewed. This includes the laser wakefield accelerator, plasma beat wave self-modulated waves driven by multiple pulses, and highly nonlinear regimes. The properties linear discussed, as well electron acceleration waves. Methods for injecting trapping electrons also discussed. Limits to energy gain summarized, including pulse diffraction,...
Multi-GeV electron beams with energy up to 4.2 GeV, 6% rms spread, 6 pC charge, and 0.3 mrad divergence have been produced from a 9-cm-long capillary discharge waveguide plasma density of ≈7×1017 cm−3, powered by laser pulses peak power PW. Preformed waveguides allow the use lower compared unguided structures achieve same beam energy. A detailed comparison between experiment simulation indicates sensitivity in this regime guiding acceleration structure input intensity, density, near-field...
Guiding of relativistically intense laser pulses with peak power 0.85 PW over 15 diffraction lengths was demonstrated by increasing the focusing strength a capillary discharge waveguide using inverse bremsstrahlung heating. This allowed for production electron beams quasimonoenergetic peaks up to 7.8 GeV, double energy that previously demonstrated. Charge 5 pC at GeV and 62 in 6 peaks, typical beam divergence 0.2 mrad.
Plasma density gradients in a gas jet were used to control the wake phase velocity and trapping threshold laser wakefield accelerator, producing stable electron bunches with longitudinal transverse momentum spreads more than 10 times lower previous experiments (0.17 0.02 MeV/c FWHM, respectively) central momenta of 0.76+/-0.02 MeV/c. Transition radiation measurements combined simulations indicated that can be as accelerator injector produce beams 0.2 MeV/c-class spread at high energies.
Physics considerations for a next-generation linear collider based on laser-plasma accelerators are discussed. The ultrahigh accelerating gradient of accelerator and short laser coupling distance between stages allows compact linac. Two regimes acceleration highly nonlinear regime has the advantages higher fields uniform focusing forces, whereas quasilinear advantage symmetric properties electrons positrons. Scaling various parameters with respect to plasma density wavelength derived....
Coherent radiation in the 0.3-3 THz range has been generated from femtosecond electron bunches at a plasma-vacuum boundary via transition radiation. The produced by laser-plasma accelerator contained 1.5 nC of charge. energy per pulse within limited 30 mrad collection angle was 3-5 nJ and scaled quadratically with bunch charge, consistent coherent emission. Modeling indicates that this broadband source produces about 0.3 microJ 100 angle, increasing transverse plasma size beam could provide...
Compact laser-plasma accelerators can produce high energy electron beams with low emittance, peak current but a rather large spread. The spread hinders the potential applications for coherent free-electron laser (FEL) radiation generation. We discuss method to compensate effects of beam by introducing transverse field variation into FEL undulator. Such gradient undulator together properly dispersed greatly reduce and jitter on performance. present theoretical analysis numerical simulations...
The temporal profile of relativistic laser-plasma-accelerated electron bunches has been characterized. Coherent transition radiation at THz frequencies, emitted the plasma-vacuum boundary, was measured through electro-optic sampling. Frequencies up to crystal detection limit 4 were observed. Comparison between data and theory indicates that from with structure shorter than $\ensuremath{\simeq}50\text{ }\text{ }\mathrm{fs}$ (root-mean-square) is emitted. measurement demonstrates both...
X-ray spectroscopy is used to obtain single-shot information on electron beam emittance in a low-energy-spread 0.5 GeV-class laser-plasma accelerator. Measurements of betatron radiation from 2 20 keV CCD and single-photon counting techniques. By matching x-ray spectra models, the bunch radius inside plasma estimated be $\ensuremath{\sim}0.1\text{ }\text{ }\ensuremath{\mu}\mathrm{m}$. Combining this with simultaneous spectra, normalized transverse as low 0.1 mm mrad, consistent...
Compact, tunable, radially symmetric focusing of electrons is critical to laser-plasma accelerator (LPA) applications. Experiments are presented demonstrating the use a discharge-capillary active plasma lens focus 100-MeV-level LPA beams. The can provide tunable field gradients in excess 3000 T/m, enabling cm-scale focal lengths for GeV-level beam energies and allowing LPA-based electron beams light sources maintain their compact footprint. For range strengths, excellent agreement with...
Having a table-top x-ray free-electron-laser source at their disposal must be the dream of every scientist. A new design based on currently available laboratory-scale laser-plasma particle accelerators shows that this should within reach before too long.
Ionization injection in a laser-plasma accelerator is studied analytically and by multi-dimensional particle-in-cell (PIC) simulations. To enable the production of low energy spread beams, we consider short region containing high atomic number gas (e.g., nitrogen) for ionization-induced trapping, followed longer using hydrogen), that is, free additional post acceleration. For broad laser pulse, ionization requires minimum normalized field a0≃1.7, assuming resonant Gaussian pulse. Effects mix...
The interaction of high-energy electrons, positrons, and photons with intense laser pulses is studied in head-on collision geometry. It shown that electrons and/or positrons undergo a cascade-type process involving multiple emissions photons. These can consequently convert into electron-positron pairs. As result charged particles quickly lose their energy developing an exponentially decaying distribution, which suppresses the emission photons, thus reducing number pairs being generated....
A method is proposed to generate femtosecond, ultralow emittance (∼10-8 m rad), electron beams in a laser-plasma accelerator using two lasers of different colors. long-wavelength pump pulse, with large ponderomotive force and small peak electric field, excites wake without fully ionizing high-Z gas. short-wavelength injection copropagating delayed respect the laser, ionizes fraction remaining bound electrons at trapping phase, generating an beam that accelerated wake.
Abstract Radiotherapy is the current standard of care for more than 50% all cancer patients. Improvements in radiotherapy (RT) technology have increased tumor targeting and normal tissue sparing. Radiations at ultra-high dose rates required FLASH-RT effects sparked interest potentially providing additional differential therapeutic benefits. We present a new experimental platform that first one to deliver petawatt laser-driven proton pulses 2 MeV energy 0.2 Hz repetition rate by means...
The general concept of radiation therapy used in conventional cancer treatment is to increase the therapeutic index by creating a physical dose differential between tumors and normal tissues through precision targeting, image guidance, beams that deliver with high conformality, e.g., protons ions. However, cure are still limited tissue toxicity, corresponding side effects. A fundamentally different paradigm for increasing has emerged recently, supported preclinical research, based on FLASH...
Abstract Construction of an e + - Higgs factory has been identified as a major goal for particle physics. Such collider will offer precise measurements the bosons couplings to other particles. A extendable in energy can also establish self-coupling, measure coupling top quark, and expand reach probe new phenomena. We propose strategy energy-extendable based on linear accelerator technology. This offers compact cost-effective design that could be realized project US. The core technologies...
The effect of asymmetric laser pulses on electron yield from a wakefield accelerator has been experimentally studied using >10(19) cm(-3) plasmas and 10 TW, >45 fs, Ti:Al2O3 laser. pulse shape was controlled through nonlinear chirp with grating pair compressor. Pulses (76 fs FWHM) steep rise positive were found to significantly enhance the compared gentle negative chirp. Theory simulation show that fast rising can generate larger amplitude wakes seed growth self-modulation instability,...
Transition radiation generated by an electron beam, produced a laser wakefield accelerator operating in the self-modulated regime, crossing plasma-vacuum boundary is considered. The angular distributions and spectra are calculated for both incoherent coherent radiation. effects of longitudinal transverse momentum on differential energy examined. Diffraction from finite extent plasma considered shown to strongly modify radiated long-wavelength This method transition generation has capability...
Laser wakefield accelerators can produce electric fields of order 10–100GV∕m, suitable for acceleration electrons to relativistic energies. The wakefields are excited by a relativistically intense laser pulse propagating through plasma and have phase velocity determined the group light pulse. Two important effects that limit distance hence net energy gain obtained an electron diffraction drive particle-wake dephasing. Diffraction focused ultrashort be overcome using preformed channels....
A long, relativistic particle beam propagating in an overdense plasma is subject to the self-modulation instability. This instability analyzed and growth rate calculated, including phase relation. The velocity of wake shown be significantly less than velocity. These results indicate that energy gain a accelerator driven by self-modulated will severely limited dephasing. In long-beam, strongly coupled regime, dephasing reached homogeneous four $e$ foldings, independent beam-plasma parameters.