Production and Study of Femtosecond Electron and X-Ray bunches with the Help of Laser Beams: Femtosecond Oscilloscopes

Dr. Karo Ispirian
Yerevan Physics Institute, Armenia

The methods for slicing of the electron beams into bunches with length of a few hundreds femtoseconds for production of X-ray pulses on 3-rd generation synchrotron radiation sources based on the interaction of electron bunches with femtosecond laser pulses in undulators are briefly reviewed. Two new methods proposed for production of shorter bunches again based on electron-laser beam interaction, but without undulators, are considered. The first uses the electron refraction in or reflection by femtosecond laser beams. The second method using the transversal deflection of electrons moving in co-propagating laser beam is considered in more details since it allows to measure the length and particle distribution in femtosecond electron bunches, i.e. to construct femtosecond oscilloscopes. The solutions of the equations of motion of electrons in short length interaction region with co propagating plane monochromatic waves with linear and circular polarizations are given which show that linear and circular transversal deflection of electrons after a few meter long field free region following the laser-electron interaction region are obtained. Compared with other experiments the proposed ones 1) use the transversal fields of laser beams, 2) do not require undulators or strong magnetic fields. Arrangements designed for the study of all the involved processes at relatively low (a few tens of keV) and high (a few tens of MeV) energies are proposed consisting of 4 parts, providing 1) primary electron bunches, 2) CO2 or Nd:Glass laser beam and its splitting with delays, 3) femtosecond slicing and 4) femtosecond measurements.