CERN Accelerating science

Article
Title	VISA IB : Ultra-High Bandwidth, High Gain SASE FEL
Author(s)	Andonian, Gerard ; Barkley-Agustsson, Ronald ; Murokh, Alex ; Pellegrini, Claudio ; Reiche, Sven ; Rosenzweig, J B ; Travish, Gil
Affiliation	(UCLA, Los Angeles, California BNL, Upton, Long Island, New YorkINFN Milano, MilanoINFN/LNF, Frascati (Roma))
Publication	2004
In:	26th International Free Electron Laser Conference and 11th FEL User Workshop 2004, Trieste, Italy, 29 Aug - 3 Sep 2004, pp.e-proc. THPOS56
Subject category	Accelerators and Storage Rings
Abstract	The results of a high energy-spread SASE FEL experiment, the intermediary experiment linking the VISA I and VISA II projects, are presented. A highly chirped beam ( 1.7%) was transported without correction of longitudinal aberrations in the ATF dogleg, and injected into the VISA undulator. The output FEL radiation displayed an uncharacteristicly large bandwidth ( 11%) with extremely stable lasing and measured energy of about 2 microJoules. Start-to-end simulations reproduce key features of the measured results and provide an insight into the mechanisms giving rise to such a high bandwidth. These analyses are described as they relate to important considerations for the VISA II experiment.