Tamar Thesis CEBAF
The continuous electron beam accelerator facility (CEBAF) atThomas Jefferson National Lab contains two anti-parallel 0.5 GeV linacs connected by five sets of recirculated arcs and a high quality 45 MeV electron beam injector with transverse emittence of less than mm-mrad and longitudinal emittence of less than keV-degrees. The linac is contains 25 crymodules, which itself are made of 8 superconducting radio-frequency cavities. Quadrupole and dipole magnets are used for steering the beam. Electrons are accelerated by microwave fields generated in klystrons and propagated through wave guides to radio-frequency accelerating cavities.
Klystron is a powerful type of microwave amplifier in which a low energy microwave signal breaks a continuous electron beam into so called bunches. After that the beam passes through the resonant waveguide, where it induces a high energy microwave signal. The transmitted microwave radiation is transported to a superconducting radio-frequency(RF) cavity where it accelerates electrons.
The electromotive force(EMF) induced in the RF cavity is roughly parallel to the beam axis and decaying to zero radially at the walls. The EMF induces charge on the interior surfaces of the cavities such that the electrons moving through the cavity see a positive charge in front of them and accelerate towards that charge.
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