Capturing Structural Dynamics in Crystalline Silicon Using Chirped Electrons from a Laser Wakefield Accelerator

He, Zhaohan; Beaurepaire, Benoit; Nees, J.; Gallé, G.; Scott, Shelley A.; Perez, Jose Roberto Sanchez; Lagally, M. G.; Krushelnick, K.; Thomas, Alexander; Faure, Jérôme

doi:10.1038/srep36224

Cited by 34 publications

(26 citation statements)

References 44 publications

(76 reference statements)

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“…Important milestones include the generation of monoenergetic electron beams [5][6][7] and sustained acceleration of more than a GeV [8][9][10][11][12][13], as well as generation and application of spatially coherent, ultrashort x-ray sources based on accelerated particle beams [14][15][16][17][18][19]. So far, this novel generation of accelerators has been used to drive applications such as x-ray imaging [20][21][22][23] and tomography [24][25][26], as well as femtosecond electron diffraction [27], femtochemistry [28], and ultrafast spectroscopy [29,30].…”

Section: Introductionmentioning

confidence: 99%

Physics of High-Charge Electron Beams in Laser-Plasma Wakefields

et al. 2020

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Laser wakefield acceleration (LWFA) and its particle-driven counterpart, particle or plasma wakefield acceleration (PWFA), are commonly treated as separate, though related, branches of high-gradient plasmabased acceleration. However, novel proposed schemes are increasingly residing at the interface of both concepts where the understanding of their interplay becomes crucial. Here, we present a comprehensive study of this regime, which we may term laser-plasma wakefields. Using datasets of hundreds of shots, we demonstrate the influence of beam loading on the spectral shape of electron bunches. Similar results are obtained using both 100-TW-class and few-cycle lasers, highlighting the scale invariance of the involved physical processes. Furthermore, we probe the interplay of dual electron bunches in the same or in two subsequent plasma periods under the influence of beam loading. We show that, with decreasing laser intensity, beam loading transitions to a beam-dominated regime, where the first bunch acts as the main driver of the wakefield. This transition is evidenced experimentally by a varying acceleration of a lowenergy witness beam with respect to the charge of a high-energy drive beam in a spatially separate gas target. Our results also present an important step in the development of LWFA using controlled injection in a shock front. The electron beams in this study reach record performance in terms of laser-to-beam energy transfer efficiency (up to 10%), spectral charge density (regularly exceeding 10 pC MeV −1), and angular charge density (beyond 300 pC μsr −1 at 220 MeV). We provide an experimental scaling for the accelerated charge per terawatt (TW) of laser power, which approaches 2 nC at 300 TW. With the expanding availability of petawatt-class (PW) lasers, these beam parameters will become widely accessible. Thus, the physics of laser-plasma wakefields is expected to become increasingly relevant, as it provides new paths toward low-emittance beam generation for future plasma-based colliders or light sources.

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Section: Introductionmentioning

confidence: 99%

Physics of High-Charge Electron Beams in Laser-Plasma Wakefields

et al. 2020

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“…Due to such tight focusing, the acceleration length is typically short (few tens of micrometers), and the LPA electron energies are on the order of a few MeVs. Operation at kHz repetition rate provides a high average current (up to tens of nA), which makes them of a great interest for ultrafast electron diffraction [19][20][21] , irradiation experiments for radiation harness assessment 22 or radio-biology 23,24 .…”

Section: Introductionmentioning

confidence: 99%

Demonstration of stable long-term operation of a kilohertz laser-plasma accelerator

Rovige

Huijts

Andriyash

et al. 2020

Phys. Rev. Accel. Beams

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We report on the stable and continuous operation of a kilohertz laser-plasma accelerator. Electron bunches with 2.6 pC charge and 2.5 MeV peak energy were generated via injection and trapping in a downward plasma density ramp. This density transition was produced in a specially designed asymmetrically shocked gas jet. The reproducibility of the electron source was also assessed over a period of a week and found to be satisfactory with similar values of the beam charge and energy. Particle in cell simulations confirm the role of the shock and the density transition in the electron injection mechanism. These results show that the reproducibility and stability of the laser-plasma accelerator are greatly enhanced on the long-term scale when using a robust scheme for density gradient injection.

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“…Such a laser experimental system is discussed in this paper, which can operate at a high repetition rate (up to ∼1 kHz). One example of 0.5 kHz laser-plasma electron acceleration is found in He et al [9], with acceleration to 100 keV by laser-wakefield acceleration and demonstrated applications in ultrafast electron diffraction [10]. Another high-repetition-rate laser wakefield acceleration study by Guénot et al [11] used a near-single-cycle laser pulse with temporal contrast better than 10 10 focused into an underdense flowing gas jet target to accelerate electrons to ∼5 MeV.…”

Section: Introductionmentioning

confidence: 99%

Relativistic electron acceleration by mJ-class kHz lasers normally incident on liquid targets

Feister¹,

Austin²,

Morrison³

et al. 2017

Opt. Express

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We report observation of kHz-pulsed-laser-accelerated electron energies up to 3 MeV in the −k laser (backward) direction from a 3 mJ laser interacting at normal incidence with a solid density, flowing-liquid target. The electrons/MeV/s.r. >1 MeV recorded here using a mJ-class laser exceeds or equals that of prior super-ponderomotive electron studies employing lasers at lower repetition-rates and oblique incidence. Focal intensity of the 40-fs-duration laser is 1.5 · 10 18 W cm −2 , corresponding to only ∼80 keV electron ponderomotive energy. Varying laser intensity confirms electron energies in the laser-reflection direction well above what might be expected from ponderomotive scaling in normal-incidence laser-target geometry. This direct, normal-incidence energy spectrum measurement is made possible by modifying the final focusing off-axis-paraboloid (OAP) mirror with a central hole that allows electrons to pass, and restoring laser intensity through adaptive optics. A Lanex-based, optics-free high-acquisition rate (>100 Hz) magnetic electron-spectrometer was developed for this study to enable shot-to-shot statistical analysis and real-time feedback, which was leveraged in finding optimal pre-plasma conditions. 3DParticle-in-cell simulations of the interaction show qualitative super-ponderomotive spectral agreement with experiment. The demonstration of a high-repetition-rate, high-flux source containing >MeV electrons from a few-mJ, 40 fs laser and a simple liquid target encourages development of future ≥kHz-repetition, fs-duration electron-beam applications.

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Capturing Structural Dynamics in Crystalline Silicon Using Chirped Electrons from a Laser Wakefield Accelerator

Cited by 34 publications

References 44 publications

Physics of High-Charge Electron Beams in Laser-Plasma Wakefields

Physics of High-Charge Electron Beams in Laser-Plasma Wakefields

Demonstration of stable long-term operation of a kilohertz laser-plasma accelerator

Relativistic electron acceleration by mJ-class kHz lasers normally incident on liquid targets

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