Towards a Compact High Efficiency FEL for Industrial Applications

TESSA-266 is an experiment with the mission to demonstrate high extraction efficiency FEL in a strongly tapered regime, with the moderate seed at UV wavelengths. The project utilizes 375 MeV electron beam at Argonne LEA facility, and employs 4-meter long Theseus undulator system, based on a helical period-by-period tapered geometry. This paper reviews the need for high efficiency FELs, and specifically a motivation and a scientific case for the TESSA-266 collaboration. It also offers some insights into the design and optimization of the experimental configuration, provides a status update, and discusses near-term plans as well as a longer-term outlook, in the context of compact FEL applications in the industry.