The resonant Wake Field Transformer concept for particle acceleration

This paper reports that in a modified version of the Wake Field Transformer, which we call the Resonant Wake Field Transformer, a train of many bunches in a hollow driver beam excites the transformer cavity. The accelerator consist of a pulsed, low frequency driver and a transformer. The driver may be a pulsed, normal conducting cavity structure, a superconducting cw structure or an induction accelerator. The hollow driver beam passes through the cavity with a timing such that the energy distribution over the bunches is a linear ramp. Subsequently, this bunch train excites a high frequency wake field transformer resulting in a field strength of 100 MV/m generated on axis. This scheme combines the features of the relativistic klystron with those of the wake field transformer concept. The major advantage of such a system is the relatively low charge density in the driving beam bunches, which corresponds to numbers actually achieved in the DESY experiment