Speaker
Description
Electrons microbunch in laser wakefield accelerators [1,2], in downstream light sources [3], and in laser modulators [4]. Precisely measuring the 3D microbunched density of the electron bunches is vital for understanding wakefield dynamics and optimizing electron-driven radiation processes. Multi-spectral coherent transition radiation (CTR) imaging measurements [5] have decoded such 3D microbunched structure, but requires independent simulation or non-optical measurement of the bunch longitudinal profile. Moreover, it took hours for the genetic reconstruction algorithm to converge, prohibiting real-time feedback and adjustment of a wakefield accelerator or free electron laser (FEL). Here, we present results of new experiments in which the spatially-averaged CTR spectrum and CTR images at eleven wavelengths were measured simultaneously, yielding in one shot all the information needed to retrieve the 3D microbunched structure. We then employed a pre-trained physics-informed neural network to reconstruct the electron density profile within one minute with better fidelity than previously [5]. Finally, by extending the measurements to interferometric CTR, with two CTR foils [6] in the diagnostic beam line, we enable single-shot, all-optical, minimal-invasive 5D visualization of the electron bunches.
Ref:
[1] Xu et al, Phys. Rev. Lett 117, 034801 (2016)
[2] Xu et al, Nat. Commun. 13:3364 (2022)
[3] Wang et al, Nature 595, 516-520 (2021)
[4] Deng et al, Nature 590, 576-579 (2021)
[5] LaBerge et al, Nat. Photon. 18 952-959 (2024)
[6] Lumpkin et al, PRL 125, 014801 (2020)
| Working group | WG5 |
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