Compact Microtron Driven by a Magnetron as an Injector of the Far Infrared Free Electron Laser

(MO-3-23)

Grigori M. Kazakevitch(b), Young Uk Jeong(a), Byung Cheol Lee(a), Sung Oh Cho(a),Sun Kook Kim(a), and Jongmin Lee(a)  

(a)Lab. for Quantum Optics, Korea Atomic Energy Research Institute, P.O.Box 105, Yusong, Taejon, 305-600, Korea, (b)Budker Institute of Nuclear Physics, Academician Lavrentyev 11, Novosibirsk, 63009

A 12 turn 8 MeV classical microtron has been improved and used as an electron beam injector of the compact far infrared (FIR) free electron laser (FEL). The microtron driven by a 2.8 GHz magnetron provides accelerated beam current up to 70 mA in the 5.5 ms width macropulse. The frequency of the magnetron is stabilized in the range of 10^-5 with the reflected wave from an accelerating cavity. The energy spread and emittance of the electron beam were measured to be less than 0.4% and 1-4 mm mrad, respectively. The temporal deviation of the bunch repetition rate has been measured by the heterodyne method. The measured value was less than 120 kHz by optimization of the microtron operating conditions for the FEL. The compact microtron was used as an injector for the FIR FEL. With the energy of electrons and macro pulse current about 7 MeV and 45 mA, correspondingly, we have measured tunable FIR FEL beam in the range of wavelength from 97 to 150 micrometer with the deep saturation.