Young Uk Jeong(a), G.M. Kazakevitch(b), Byung Cheol Lee(a), Sun Kook Kim(a), Sung Oh Cho(a), Byung Heon Cha(a), Jongmin Lee(a), P.D. Vobly(b), N.G. Gavrilov(b), V.V. Kubarev(b), and G.N. Kulipanov(b)
(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, Lavrentyev ave. 11, 630090 Novosibirsk, Russia
The KAERI compact far infrared (FIR) free-electron laser (FEL) has been operated successfully in the wavelength range of 97-150 micrometer[1]. It is the first demonstration of FEL lasing by using a magnetron-based classical microtron. Stabilization of the magnetron frequency could be done by the feedback of the RF wave from an accelerating cavity having a high Q-value. The energy of the electron beam is 6.5 MeV. The average current and the pulse duration of the electron beam macropulse are 45 mA and 5.5 microsecond, respectively. In order to get enough gain of the FEL with the low beam current, we developed a high precision undulator consisting of 80 periods with 25 mm period. The field strength of the undulator can be changed from 4.8 to 6.8 kG and the amplitude deviation is only 0.05% in r.m.s value. The measured power of the FEL is more than 50 W for the macropulse having the duration of 4 microsecond. The fluctuation of the measured power turns out to be less than 1%. The spectral width of the FEL was measured to be 0.5% of the central wavelength. The FEL system except racks for controlling units is located inside the area of 3x4 m[1] Jongmin Lee, et al., Nucl. Instr. and Meth., A 407 (1998) 161.
