Free electron laser-FEL-study in Institute of Nuclear Physics of MSU

The possibility of creation of a source of coherent shortwave radiation on the basis of the RM of Moscow State University (MSU) facility was considered. The RM is designed to obtain accelerated electrons with a variable energy of 7-180 MeV at high quality of beam: the homogeneity of energy is 0.0001, the beam emittance is not higher than 0.01 mm.mrad. The beam current is a continuous sequence of electron pulses with the duration of 3-4 ps following at a frequency of 2.45 GHz and the average current of 100 mA. A special operation mode of the acceleration is provided for duty cycle decreasing by 100-300 times and the amplitude of current pulses 1-10 A. Two operation regimes of the FEL are possible. At the standard undulator parameters (length and number of periods are 2.5 cm and 100, B=5 kG, undulator factor is K=0.5-1, optical length is 3-5 m) positive gain in the single-particle regime is realised in the 5-170 mkm band. Low emittance permits to provide the collective amplification regime of FEL with channelling radiation. In this case the positive gain may be achieved in the wavelength region of λs< 1 mkm