cSTART – Status on the compact electron STorage ring for non-equilibrium Accelerator Research and Technology

The goals of the compact STorage ring for Accelerator Research and Technology (cSTART) at Karlsruhe Institute of Technology (KIT), are to emonstrate the storage of ultra-short electron bunches and to investigate their non-equilibrium dynamics. Furthermore, it aims to study the application of laser-plasma accelerators (LPAs) as injectors for storage rings. To achieve these goals, cSTART has a specifically designed flexible magnetic lattice with large momentum acceptance that can be tuned to ultra-low momentum compaction factor operation. cSTART will have two independent injectors: FLUTE (Ferninfrarot Linac und Test Experiment) and an LPA. In 2024, the collaboration between KIT, RI Research Instruments GmbH, and its subcontractors completed the Technical Design Report (TDR), followed by the Final Design Report (FDR) until mid-2026. Most magnets and power sup- plies for the injection line (IL), which will connect FLUTE to the storage ring, are already available at KIT. Some of the diagnostics were delivered and are being tested at KIT, the others are in production. Magnets, power supplies, and vacuum chambers for the storage ring are currently in production. This article provides an overview of the current status and outlines the next steps of the cSTART project.