Extreme electron beams for High Energy Physics and fundamental science experiments*

This contribution discusses a research program based at the FACET-II facility at SLAC dedicated to generating, diagnosing and optimizing extreme electron beams to serve the next generation of HEP and fundamental science experiments. These extreme beams will have unprecedented properties: 10s - 100s of nm bunch length, MA-scale peak current, and peak electric fields exceeding 1 TV/m. Notable applications of these bunches are future short bunch colliders¹, strong field quantum electrodynamics phenomena², TeV/m plasma-based accelerators³, and fundamental instabilities in astrophysical processes leading to bright gamma-ray bursts⁴. Our approach towards generating these extreme beams leverages the ultra-high longitudinal brightness and strong chirps naturally present in plasma-accelerated beams to further compress the ~um scale bunches after the exit of a plasma to high current spikes of nm length. We present simulation studies identifying working points for FACET-II experiments which will probe the parameter space of extremely compressed beams for different applications. We discuss hardware and diagnostic development which will enable measurement and optimization of compressed beam properties.

1. V. Yakimenko, et al., PRL., vol. 122, p. 190404, 19 May 2019.

2. A. Matheron, et al., Commun. Phys. 6, 141 (2023)

3. J. Rosenzweig, et al., Vol 653, 11, NIMA, Feb. (2011)

4. A. Benedetti, et al., Nature Photonics, vol. 12, no. 6, pp. 319–323, Apr. 2018