Beam-energy-spread adjustment using cell-timing asynchronization

The pulsed high-current beams in Linear Induction Accelerator required by radiography gain their energy from the induction electric field generated at the acceleration gap. Beam loading effect determines that particles at different longitudinal position within a bunch get unequal gain of energy: particles at the beam head and tail have their energy increase faster than those at the main part, which consequently results in an energy spread increase. Since the first observations, significant efforts have been made to measure and restrain this energy spread growth. In this paper, a new method is proposed to mitigate the energy spread growth through regulating the energy gain of particles within a bunch by cell-timing asynchronization. Initial results from experiments on the accelerator show that the beam energy spread can be effectively controlled with this method.