Bright x-ray radiation from plasma bubbles in an evolving laser wakefield accelerator

Bloom, Michael S.; Streeter, Matthew; Kneip, S.; Bendoyro, R. A.; Cheklov, O; Cole, J. M.; Doepp, Andreas; Hooker, C. J.; Holloway, J.; Jiang, Jason Zheng; Lopes, Nelson; Nakamura, Hirotaka; Norreys, P.; Rajeev, P. P.; Symes, D. R.; Schreiber, Jörg; Wood, Jonathan; Wing, M.; Najmudin, Z.; Mangles, Stuart

doi:10.1103/physrevaccelbeams.23.061301

Cited by 8 publications

(2 citation statements)

References 33 publications

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“…The average plasma electron density varied by 4% over the training dataset, as illustrated by the small perturbations to the density profile observed in Figure 8(a). A more significant effect is seen on the electron spectra in Figure 8(b), with the peak energy shifting higher as the average density drops, as expected for a dephasinglimited LWFA [50,51] . The effect on the spectrum is much smaller than that seen to be caused by the laser energy variation in Figure 7.…”

Section: Lwfa Prediction Resultssupporting

confidence: 67%

Laser Wakefield Accelerator modelling with Variational Neural Networks

Streeter

Colgan²,

Cobo³

et al. 2023

High Pow Laser Sci Eng

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A machine learning model was created to predict the electron spectrum generated by a GeVclass laser wakefield accelerator. The model was constructed from variational convolutional neural networks which mapped the results of secondary laser and plasma diagnostics to the generated electron spectrum. An ensemble of trained networks was used to predict the electron spectrum and to provide an estimation of the uncertainty on that prediction. It is anticipated that this approach will be useful for inferring the electron spectrum prior undergoing any process which can alter or destroy the beam. In addition, the model provides insight into the scaling of electron beam properties due to stochastic fluctuations in the laser energy and plasma electron density.

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Section: Lwfa Prediction Resultssupporting

confidence: 67%

Laser Wakefield Accelerator modelling with Variational Neural Networks

Streeter

Colgan²,

Cobo³

et al. 2023

High Pow Laser Sci Eng

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“…The energy gain for the lowest density does not follow this trend. This is because selfinjection occurs later within the gas cell for lower densities, which means the acceleration length can be truncated by the end of the gas cell rather than the dephasing length [23]. The highest electron bunch charge was seen at a plasma density of (4.4 ± 0.2) × 10 18 cm −3 .…”

Section: Optimisation Of the X-ray Source With Respect To Densitymentioning

confidence: 99%

Characterisation of a laser plasma betatron source for high resolution x-ray imaging

Finlay

Gruse

Thornton

et al. 2021

Plasma Phys. Control. Fusion

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We report on the characterisation of an x-ray source, generated by a laser-driven plasma wakefield accelerator. The spectrum of the optimised source was consistent with an on-axis synchrotron spectrum with a critical energy of 13.8 +2.2 −1.9 keV and the number of photons per pulse generated above 1 keV was calculated to be 6 +1.2 −0.9 × 10 9 . The x-ray beam was used to image a resolution grid placed 37 cm from the source, which gave a measured spatial resolution of 4 µm × 5 µm. The inferred emission region had a radius and length of 0.5 ± 0.2 µm and 3.2 ± 0.9 mm respectively. It was also observed that laser damage to the exit aperture of the gas cell led to a reduction in the accelerated electron beam charge and a corresponding reduction in x-ray flux due to the change in the plasma density profile.

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Extended X-ray absorption spectroscopy using an ultrashort pulse laboratory-scale laser-plasma accelerator

Kettle,

Colgan,

Los

et al. 2024

Commun Phys

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Laser-driven compact particle accelerators can provide ultrashort pulses of broadband X-rays, well suited for undertaking X-ray absorption spectroscopy measurements on a femtosecond timescale. Here the Extended X-ray Absorption Fine Structure (EXAFS) features of the K-edge of a copper sample have been observed over a 250 eV window in a single shot using a laser wakefield accelerator, providing information on both the electronic and ionic structure simultaneously. This capability will allow the investigation of ultrafast processes, and in particular, probing high-energy-density matter and physics far-from-equilibrium where the sample refresh rate is slow and shot number is limited. For example, states that replicate the tremendous pressures and temperatures of planetary bodies or the conditions inside nuclear fusion reactions. Using high-power lasers to pump these samples also has the advantage of being inherently synchronised to the laser-driven X-ray probe. A perspective on the additional strengths of a laboratory-based ultrafast X-ray absorption source is presented.

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Bright x-ray radiation from plasma bubbles in an evolving laser wakefield accelerator

Cited by 8 publications

References 33 publications

Laser Wakefield Accelerator modelling with Variational Neural Networks

Laser Wakefield Accelerator modelling with Variational Neural Networks

Characterisation of a laser plasma betatron source for high resolution x-ray imaging

Extended X-ray absorption spectroscopy using an ultrashort pulse laboratory-scale laser-plasma accelerator

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