2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/84513I summarise the R&D programme on a nanosecond-timescale fast-feedback system for luminosity optimisation at the linear collider4 pages, 3 figures. Contributed to Proceedings, Snowmass 2001Accelerator PhysicsOptimising the linear collider luminosity: feedback on nanosecond timescalestext