Compact spectroscopy of keV to MeV X-rays from a laser wakefield accelerator.
Ontology highlight
ABSTRACT:
SUBMITTER: Hannasch A
PROVIDER: S-EPMC8277848 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:Laser-plasma wakefield accelerators have seen tremendous progress, now capable of producing quasi-monoenergetic electron beams in the GeV energy range with few-femtoseconds bunch duration. Scaling these accelerators to the nanocoulomb range would yield hundreds of kiloamperes peak current and stimulate the next generation of radiation sources covering high-field THz, high-brightness X-ray and γ-ray sources, compact free-electron lasers and laboratory-size beam-driven plasma accelerators. However, accelerators generating such currents operate in the beam loading regime where the accelerating field is strongly modified by the self-fields of the injected bunch, potentially deteriorating key beam parameters. Here we demonstrate that, if appropriately controlled, the beam loading effect can be employed to improve the accelerator's performance. Self-truncated ionization injection enables loading of unprecedented charges of ∼0.5 nC within a mono-energetic peak. As the energy balance is reached, we show that the accelerator operates at the theoretically predicted optimal loading condition and the final energy spread is minimized.Higher beam quality and stability are desired in laser-plasma accelerators for their applications in compact light sources. Here the authors demonstrate in laser plasma wakefield electron acceleration that the beam loading effect can be employed to improve beam quality by controlling the beam charge.
| S-EPMC5591198 | biostudies-literature
Project description:The phase velocity of the wakefield of a laser wakefield accelerator can, theoretically, be manipulated by shaping the longitudinal plasma density profile, thus controlling the parameters of the generated electron beam. We present an experimental method where using a series of shaped longitudinal plasma density profiles we increased the mean electron peak energy more than 50%, from 175 ± 1 MeV to 262 ± 10 MeV and the maximum peak energy from 182 MeV to 363 MeV. The divergence follows closely the change of mean energy and decreases from 58.9 ± 0.45 mrad to 12.6 ± 1.2 mrad along the horizontal axis and from 35 ± 0.3 mrad to 8.3 ± 0.69 mrad along the vertical axis. Particle-in-cell simulations show that a ramp in a plasma density profile can affect the evolution of the wakefield, thus qualitatively confirming the experimental results. The presented method can increase the electron energy for a fixed laser power and at the same time offer an energy tunable source of electrons.
| S-EPMC6677811 | biostudies-literature
Project description:Laser-wakefield accelerators are compact devices capable of delivering ultra-short electron bunches with pC-level charge and MeV-GeV energy by exploiting the ultra-high electric fields arising from the interaction of intense laser pulses with plasma. We show experimentally and through numerical simulations that a high-energy electron beam is produced simultaneously with two stable lower-energy beams that are ejected in oblique and counter-propagating directions, typically carrying off 5-10% of the initial laser energy. A MeV, 10s nC oblique beam is ejected in a 30°-60° hollow cone, which is filled with more energetic electrons determined by the injection dynamics. A nC-level, 100s keV backward-directed beam is mainly produced at the leading edge of the plasma column. We discuss the apportioning of absorbed laser energy amongst the three beams. Knowledge of the distribution of laser energy and electron beam charge, which determine the overall efficiency, is important for various applications of laser-wakefield accelerators, including the development of staged high-energy accelerators.
| S-EPMC5345066 | biostudies-literature
Project description:Laser-plasma particle accelerators could provide more compact sources of high-energy radiation than conventional accelerators. Moreover, because they deliver radiation in femtosecond pulses, they could improve the time resolution of X-ray absorption techniques. Here we show that we can measure and control the polarization of ultra-short, broad-band keV photon pulses emitted from a laser-plasma-based betatron source. The electron trajectories and hence the polarization of the emitted X-rays are experimentally controlled by the pulse-front tilt of the driving laser pulses. Particle-in-cell simulations show that an asymmetric plasma wave can be driven by a tilted pulse front and a non-symmetric intensity distribution of the focal spot. Both lead to a notable off-axis electron injection followed by collective electron-betatron oscillations. We expect that our method for an all-optical steering is not only useful for plasma-based X-ray sources but also has significance for future laser-based particle accelerators.
| S-EPMC3778521 | biostudies-literature
Project description:Technology based on high-peak-power lasers has the potential to provide compact and intense radiation sources for a wide range of innovative applications. In particular, electrons that are accelerated in the wakefield of an intense laser pulse oscillate around the propagation axis and emit X-rays. This betatron source, which essentially reproduces the principle of a synchrotron at the millimeter scale, provides bright radiation with femtosecond duration and high spatial coherence. However, despite its unique features, the usability of the betatron source has been constrained by its poor control and stability. In this article, we demonstrate the reliable production of X-ray beams with tunable polarization. Using ionization-induced injection in a gas mixture, the orbits of the relativistic electrons emitting the radiation are reproducible and controlled. We observe that both the signal and beam profile fluctuations are significantly reduced and that the beam pointing varies by less than a tenth of the beam divergence. The polarization ratio reaches 80%, and the polarization axis can easily be rotated. We anticipate a broad impact of the source, as its unprecedented performance opens the way for new applications.
| S-EPMC6062047 | biostudies-literature
Project description:Recent developments in laser-wakefield accelerators have led to compact ultrashort X/γ-ray sources that can deliver peak brilliance comparable with conventional synchrotron sources. Such sources normally have low efficiencies and are limited to 107-8 photons/shot in the keV to MeV range. We present a novel scheme to efficiently produce collimated ultrabright γ-ray beams with photon energies tunable up to GeV by focusing a multi-petawatt laser pulse into a two-stage wakefield accelerator. This high-intensity laser enables efficient generation of a multi-GeV electron beam with a high density and tens-nC charge in the first stage. Subsequently, both the laser and electron beams enter into a higher-density plasma region in the second stage. Numerical simulations demonstrate that more than 1012 γ-ray photons/shot are produced with energy conversion efficiency above 10% for photons above 1 MeV, and the peak brilliance is above 1026 photons s-1 mm-2 mrad-2 per 0.1% bandwidth at 1 MeV. This offers new opportunities for both fundamental and applied research.
| S-EPMC7259925 | biostudies-literature
Project description:The interaction of intense particle bunches with plasma can give rise to plasma wakes1,2 capable of sustaining gigavolt-per-metre electric fields3,4, which are orders of magnitude higher than provided by state-of-the-art radio-frequency technology5. Plasma wakefields can, therefore, strongly accelerate charged particles and offer the opportunity to reach higher particle energies with smaller and hence more widely available accelerator facilities. However, the luminosity and brilliance demands of high-energy physics and photon science require particle bunches to be accelerated at repetition rates of thousands or even millions per second, which are orders of magnitude higher than demonstrated with plasma-wakefield technology6,7. Here we investigate the upper limit on repetition rates of beam-driven plasma accelerators by measuring the time it takes for the plasma to recover to its initial state after perturbation by a wakefield. The many-nanosecond-level recovery time measured establishes the in-principle attainability of megahertz rates of acceleration in plasmas. The experimental signatures of the perturbation are well described by simulations of a temporally evolving parabolic ion channel, transferring energy from the collapsing wake to the surrounding media. This result establishes that plasma-wakefield modules could be developed as feasible high-repetition-rate energy boosters at current and future particle-physics and photon-science facilities.
| S-EPMC8891014 | biostudies-literature
Project description:Plasma wakefield accelerators are capable of sustaining gigavolt-per-centimeter accelerating fields, surpassing the electric breakdown threshold in state-of-the-art accelerator modules by 3-4 orders of magnitude. Beam-driven wakefields offer particularly attractive conditions for the generation and acceleration of high-quality beams. However, this scheme relies on kilometer-scale accelerators. Here, we report on the demonstration of a millimeter-scale plasma accelerator powered by laser-accelerated electron beams. We showcase the acceleration of electron beams to 128 MeV, consistent with simulations exhibiting accelerating gradients exceeding 100 GV m-1. This miniaturized accelerator is further explored by employing a controlled pair of drive and witness electron bunches, where a fraction of the driver energy is transferred to the accelerated witness through the plasma. Such a hybrid approach allows fundamental studies of beam-driven plasma accelerator concepts at widely accessible high-power laser facilities. It is anticipated to provide compact sources of energetic high-brightness electron beams for quality-demanding applications such as free-electron lasers.
| S-EPMC8129089 | biostudies-literature
Project description:Plasma wakefield accelerators have been used to accelerate electron and positron particle beams with gradients that are orders of magnitude larger than those achieved in conventional accelerators. In addition to being accelerated by the plasma wakefield, the beam particles also experience strong transverse forces that may disrupt the beam quality. Hollow plasma channels have been proposed as a technique for generating accelerating fields without transverse forces. Here we demonstrate a method for creating an extended hollow plasma channel and measure the wakefields created by an ultrarelativistic positron beam as it propagates through the channel. The plasma channel is created by directing a high-intensity laser pulse with a spatially modulated profile into lithium vapour, which results in an annular region of ionization. A peak decelerating field of 230 MeV m(-1) is inferred from changes in the beam energy spectrum, in good agreement with theory and particle-in-cell simulations.
| S-EPMC4895722 | biostudies-literature
Project description:The exploration of new acceleration mechanisms for compactly delivering high-energy particle beams has gained great attention in recent years. One alternative that has attracted particular interest is the plasma-based wakefield accelerator, which is capable of sustaining accelerating fields that are more than three orders of magnitude larger than those of conventional radio-frequency accelerators. In this device, acceleration is generated by plasma waves that propagate at nearly light speed, driven by intense lasers or charged particle beams. Here, we report on the direct visualization of the entire plasma wake dynamics by probing it with a femtosecond relativistic electron bunch. This includes the excitation of the laser wakefield, the increase of its amplitude, the electron injection, and the transition to the beam-driven plasma wakefield. These experimental observations provide first-hand valuable insights into the complex physics of laser beam-plasma interaction and demonstrate a powerful tool that can largely advance the development of plasma accelerators for real-time operation.
| S-EPMC10836718 | biostudies-literature