Speaker
Description
FACET is a transformative facility that pioneered plasma wakefield acceleration. This contribution proposes ideas for the continuation of FACET-II, dubbed “FACET-III”, with a focus on ultrabright electron beams and light sources such as XFELs to serve a wide range of needs in Basic Energy Sciences, industry, accelerator and HEP R&D, and the international user community.
FACET is the only linac-based facility worldwide capable of providing dephasing-free 100 GV/m plasma wakefields driven by tens-of-kA, 10 GeV electron drive beams together with synchronized laser pulses. These capabilities enabled the first-ever demonstrations of density down-ramp injection in PWFA [1] and the plasma photocathode technique [2] as pathways toward ultrabright beams. The facility is uniquely suited for further development into a platform that simultaneously acts as a beam-brightness transformer and energy booster [3], while also functioning as a stability transformer [4].
If ultrahigh brightness operation were established as a central design backbone, FACET-III could produce multi-kA, dark-current-free, attosecond-scale electron beams with brightness orders of magnitude beyond LCLS. This would open a new research frontier and may enable XFELs with photon energies exceeding 60 keV already at 2.3 GeV and true diffraction-before-destruction imaging [5], imaging of electronic motion on their natural time and length scale [8], potentially extending toward several hundred keV at higher electron energies that are straightforward within reach with 10 GeV driver beams [6,9]. Such capabilities would strongly motivate and inspire advanced undulator development required to fully exploit the ultrahigh beam brightness, and overall act as condensation point for next-generation XFEL R&D co-located with LCLS and LCLS-II. Attosecond ultrabright electron beams and derived hard photon sources could also enable precision QED studies and many additional applications [7].
FACET-III as an ultrahigh-brightness machine would constitute a globally unique research infrastructure, filling a critical gap in the worldwide accelerator and light-source landscape.
[1] All-optical density downramp injection in electron-driven plasma wakefield accelerators, D. Ullmann et al.., Phys. Rev. Research 3, 043163, 2021
[2] Deng, Karger et al., Nat. Phys. 15, 1156–1160 (2019)
[3] Plasma photocathode beam brightness transformer for laser-plasma-wakefield accelerators, DOE SBIR DESC0009533 (RadiaBeam)
[4] Campbell et al.,Phys. Rev. Research 8, 013273 (2026)
[5] Habib et al., Nat. Comm. 14, 1054 (2023)
[6] https://indico.global/event/5645/contributions/45376/
[7] Applications enabled by plasma photocathode PWFA calibre XFELs are included in the UKXFEL Science Case, see https://www.xfel.ac.uk/
[8] https://www.energy.gov/science/bes/articles/ice-cold-plasma-electron-beams-prepare-power-future-hard-x-ray-laser-beams
[9] F. Habib et al., Plasma accelerator-based ultrabright x-ray beams from ultrabright electron beams," Proc. SPIE 11110, Advances in Laboratory-based X-Ray Sources, Optics, and Applications VII, 111100A (9 September 2019)
| Working group | WG3 |
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