Author: Friedman, A.
Paper Title Page
MOP017 Measurement of the Output Power in Millimeter Wave Free Electron Laser using the Electro Optic Sampling Method 50
  • A. Klein
    Israeli Free Electron Laser, Ariel, Israel
  • A. Abramovich
    Ariel University Center of Samaria, Faculty of Engineering, Ariel, Israel
  • D. Borodin, A. Friedman
    Ariel University, Ariel, Israel
  • H. S. Marks
    University of Tel-Aviv, Faculty of Engineering, Tel-Aviv, Israel
  Funding: this work funded in part by Israel Minstry of Defence
In this experimental work an electro optic (EO) sampling method was demonstrated as a method to measure the output power of an Electrostatic Accelerator Free Electron Laser (EA-FEL). This 1.4 MeV EA-FEL was designed to operate at the millimeter wavelengths and it utilizes a corrugated waveguide and two Talbot effect quasi-optical reflectors with internal losses of ~30%. Millimeter wave radiation pulses of 10 μs at a frequency of about 100 GHz with peak power values of 1-2 kW were measured using conventional methods with an RF diode. Here we show the employment of an electro-optic sampling method using a ZnTe nonlinear crystal. A special quasi optical design directs the EA-FEL power towards the ZnTe nonlinear crystal, placed in the middle of a cross polarized configuration, coaxially with a polarized HeNe laser beam. The differences in the ZnTe optical axis due to the EA-FEL power affects the power levels of the HeNe laser transmission. This was measured using a polarizer and a balanced amplifier detector. We succeeded in obtaining a signal which corresponds to the theoretical calculation.
TUP081 Configuration and Status of the Israeli THz Free Electron Laser 553
  • A. Friedman, N. Balal, V.L. Bratman, E. Dyunin, Yu. Lurie, E. Magori
    Ariel University, Ariel, Israel
  • A. Gover
    University of Tel-Aviv, Faculty of Engineering, Tel-Aviv, Israel
  Funding: This project is funded in part by Israel Ministry of Defense.
A THz FEL is being built in Ariel University. This project is a collaboration between Ariel University, and Tel Aviv University. Upon completion it is intended to become a user facility. The FEL is based on a compact photo cathode gun (60 cm) that will generate an electron beam at energies of 4.5 - 6.5 MeV. The pulses are planned to be of 300 pico Coulomb for a single pulse, and of up to 1.5 nano Coulomb for a train of pulses. The FEL is designed to emit radiation between 1 and 5 THz. It is planned to operate in the super radiance regime. The configuration of the entire system will be presented, as well as theoretical and numerical results for the anticipated output of the FEL, which is in excess of 150 KW instantaneous power. The bunching of the electron bean will be achieved by mixing two laser beams on the photo-cathode. The compression of the beam will be achieved be introducing an energy chierp to the beam and passing it through a helical chicane. We plan on compressing the single pulse to less than 150 femto seconds. The status of the project at the time of the conference will be presented.
poster icon Poster TUP081 [3.276 MB]  
THP008 Evolution of a Warm Bunched Electron Beam in a Free Drift Region 692
  • B. Maly, A. Friedman
    Ariel University, Ariel, Israel
  The state of the art of FELs development at present is "Table-Top X Ray Free Electron Lasers". Almost any such scheme involves a pre-bunched electron beam. In this paper we will analyze the evolution and "survivability" of bunching introduced into the beam in the free drift region prior to the wiggler. We examined analytically the first order degradation in beam bunching due to space charge effect. It will be shown that there is a limited interaction region, characterized by an exponential decay of the bunching factor, having a length inversely proportional to the square of the electron beam normalized temperature, followed by a stable bunch region. We will present examples of the effect for several schemes of X Ray and Tera Hertz FELs considered or being constructed presently.