German-Armenian Student Course on Accelerator Physics

Generation and acceleration of ultrashort relativistic electron beams


Presently, electron accelerators, besides serving the nuclear physics, are playing an important role in frontier research in life, materials and environmental sciences. The study of the dynamics of processes in the nano-world requires ultrashort pulses of electron and photon beams to exploit the matter. The practical course is devoted to the generation of ultrashort electron beams by an ultrafast powerful ultraviolet (UV) laser through photoemission and simultaneous particle acceleration by high-gradient electric fields in a radio-frequency (RF) cavity to relativistic energies.

The course is focused on the generation and formation of sub-picosecond long relativistic electron bunches. Based on the 5 MeV electron energy at the AREAL laser-driven facility, the students will study the electron photoemission process using a femtosecond UV laser, the beam acceleration to relativistic energy in the RF cavity, the material quantum efficiency, Schottky effect and space charge limits. The dependence of generated electron charge on laser energy; quantum efficiency of the photocathode material; and on presence of a high gradient accelerating field will all be measured, and the space charge limit due to collective Coulomb forces of the electron bunch generation will be considered. Skills on accelerator operation and beam diagnostics and instrumentation will be gained.