Investigation of Raman free-electron lasers with a bifilar helical small-period wiggler

A Raman free-electron laser with a novel bifilar helical small-period wiggler is presented. The magnetic characteristics of such a wiggler are measured, and the maximum transverse field of the wiggler as high as 1500 G has been obtained with the wiggler period 10 mm and gap 15 mm. The experimental results indicated that the free-electron laser operates in the range of 3 mm when using a limited pulse duration of electron beam (300 keV/400 A, 50 ns), and the maximum laser power of 600 kW is observed, corresponding to electron efficiency of 0.5%.<
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