Speaker
Description
The design of future circular colliders will push beam currents and luminosities to unprecedented levels. Beam halo surrounding the main beam can deposit enough energy to melt conventional metal collimators and damage downstream components within a short time. Such damage was already observed during SuperKEKB commissioning [1]. A possible solution is to use Compton scattering to deflect halo electrons, effectively using a laser as a non-material collimator [2].
Previous studies have explored laser-Compton scattering for beam-intensity control in FCC-ee and laboratory tests at FACET-II [3,4]. In this work, we instead focus on laser-based halo collimation using tailored annular intensity profiles. We compare several schemes for generating donut-shaped beams, including axicons and spiral phase plates, and evaluate their suitability for different interaction geometries. We perform numerical analyses of the laser beam profile and single-electron scattering probability using SLAC FACET-II laser parameters. Based on these results, we propose a near-term experimental plan to test this concept in an upcoming FACET-II beamtime.
[1] S. Terui et al., “Collimator challenges at SuperKEKB and their countermeasures using nonlinear collimator,” Phys. Rev. Accel. Beams 27, 081001 (2024). https://doi.org/10.1103/PhysRevAccelBeams.27.081001
[2] F. Zimmermann, “New final focus concepts at 5 TeV and beyond,” AIP Conf. Proc. 472, 103–117 (1999). https://doi.org/10.1063/1.58898
[3] F. Zimmermann and T. O. Raubenheimer, “Controlling e+/e− circular collider bunch intensity by laser Compton scattering,” in Proc. IPAC’22, Bangkok, Thailand, pp. 1695–1698 (2022). https://doi.org/10.18429/JACoW-IPAC2022-WEPOST010
[4] C. Munting, P. Kicsiny, E. Barbi, N. Gonzalez, S. Gessner, and I. Drebot, “Laboratory Tests of Laser Control of Electron Beams for Future Colliders,” arXiv:2601.19865 [physics.acc-ph] (2026). https://arxiv.org/abs/2601.19865
| Working group | WG7 |
|---|