2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/223272The ILC baseline design for the positron source is based on a helical undulator and will deliver a positron beam with a polarization of 30% or more. In this contribution the need for fast reversal of the positron helicity is discussed.To appear in the proceedings of International Linear Collider Workshop (LCWS08 and ILC08), Chicago, Illinois, 16-20 Nov 2008Instrumentation and Detectorstext