Transformation of energy and current waveforms of an intense relativistic electron beam using cavities

Experiments on transformation of energy and beam current waveforms of an intense relativistic electron beams with cavities located in the drift tube were carried out. An intense electron beam with energy of 550 keV, current of 3 kA and duration of 12 ns was injected into a drift tube. A coaxial cavity connected with the drift tube via a gap was utilized to transform the time evolution of electron energies of the beam. With duration of the round trip time for light of the cavity, the former part of the beam lost the energy and following part of the beam gained the energy. A cylindrical cavity with large diameter whose space-charge limiting current was smaller than the injected current was located behind the coaxial cavity to change the current waveform of the beam. The beam current was decreased gradually to the limiting current by elongating the cavity length. Trapezoidal waveforms of injected electron energy and beam current were transformed to the time-increasing waveforms after the cavities.