What is FEL

What is FEL?

Free Electron Laser (FEL) are the high power lasers which were the prime candidates to produce the intense laser beams intended to destroy attacking balistic missiles in the "star wars" program. This veteran of the cold war has made a vocational conversion in the post cold war era. Presently it is being used mostly as a very flexible tuneable source of coherent radiation for scientific, technological and medical research which is conducted in big user facilities.

At the present time there are more than 50 FEL facilities in operation and development all over the world - primarily in the U.S., Europe and Asia. FELs extract their radiation from the kinetic energy of an accelerated electron beam. Their operating wavelengths can range over a wide spectral range from microwaves to X-Ray, depending on the energy of the accelerator. The most advanced FEL projects produce coherent high brightness high intensity X-Ray radiation [links to LCLS, DESY, FERMI, SACLA]. No other kinds of laser can operate in this wavelength regime. Present activity in this field is aimed to development of compact short wavelength coherent radiation sources based on laser acceleration.

Links:

LCLS: https://portal.slac.stanford.edu/sites/lcls_public/Pages/Default.aspx

DESY:http://www.desy.de/index_eng.html

FERMI:https://www.elettra.trieste.it/lightsources/fermi.html

SACLA:http://www.lightsources.org/facility/sacla

The Israeli FEL Project

There are two main FEL projects in operation and under development by a collaboration of Tel-Aviv University and Ariel University. The facilities are situated in the Center for Radiation Sources and Applications in Ariel.

1)A Tandem electrostatic accelerator mm-wave FEL

The Israeli Tandem FEL is one out of few projects in the world which are based on electrostatic accelerators. Only such devices can operate with a continuous wave (cw) or in a quasi-cw (long pulse) mode. All other FELs, are based on pulsed accelerators and can produce, therefore, only a pulsed waveform. Electrostatic Accelerator FELs (EA-FEL) have the potential for operating with high average power, high energy conversion efficiency and high spectral purity (narrow linewidth).

The accelerator development work and the subsequent EA-FEL project were established originaly in 1987 in the Weitzmann Institute by a Consortium of Tel-Aviv University, Rafael, Nuclear Research Center Negev, and Weizmann Institute. They were initially funded by the Israeli Ministry of Science, Ministry of Energy and Infrastructure, Ministry of Defense, the Israel Academy of Science, U.S.-Israel B.S.F. and the Meyer Foundation.

2)A Super-radiant THz FEL based on a photocathode RF gun injector (under development).