The VISA experiment examined the properties of SASE FEL process in a saturating system. The experiment utilized a high brightness 71 MeV electron beam at the Brookhaven ATF, and a novel strong focusing undulator. Saturated gain of 2x108, with a record short power gain length under 18 cm, was obtained at 842 nm. Measurements of spectral and angular properties of SASE radiation are discussed, and the results are compared to theory and to start-to-end simulations of the system. The observed effects of an electron beam compression due to nonlinearities in the beam transport to the undulator are analyzed and compared to the theoretical and numerical models. Plans for future experiments using chirped beams and a compressor at the ATF are discussed.


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