GENERATION OF MICROWAVE FREE-ELECTRON LASER-RADIATION USING SHEET ELECTRON-BEAM AND PLANAR ELECTROMAGNET WIGGLER

An experimental study of sheet electron beam propagation through a pla nar electromagnet wiggler and generation of microwave radiation by fre e-electron laser action has been carried out. The space charge dominat ed sheet electron beam of energy similar to 100-200 keV, current 50-15 0 A, and pulsewidth of 100-150 ns was propagated through a 20-period p lanar electromagnetic wiggler. Significant enhancement in the beam tra nsmission through the wiggler was observed as the wiggler magnetic fie ld was increased, even though the operating regime of the beam is spac e charge dominated. Generation of microwave radiation in E-band (60-90 GHz) was also observed when the sheet electron beam is injected throu gh the wiggler in the presence of wiggler magnetic field.