Laser Compton backscattering for precision beam intensity control in the FCC-ee electron-positron collider

In this study, we explore the application of laser-driven Compton backscattering (CBS) as a method to precisely adjust and regulate the intensity of colliding particle bunches in the Future Circular Collider (FCC-ee). Maintaining a tightly controlled charge balance between collision partner bunches within a 3–5% tolerance is critical for mitigating the impact of beamstrahlung on bunch length and preventing flip-flop instabilities. We present a realistic design for the CBS optical beamline and provide detailed simulation results that demonstrate its performance in the FCC-ee. Our analysis includes the distribution of scattered positrons, illustrating the feasibility of CBS for achieving the stringent intensity control requirements in this next-generation collider.