Ultra Low Charge Bunch Arrival-time Monitor – fs Resolution for ultra low bunch charge pulsed- and CW-beams

In this project, a new concept for an ultra-wideband pickup structure for frequencies up to at least 100 GHz and a novel Electro-optical modulator for RF frequencies up to 100 GHz and low drive voltages. For CW operation at ELBE the bandwidth will be increased to at least 100 GHz when the beam pipe dimension remains constant at 43 mm. For ultra-low charge operation down to 1 pC at XFEL the beampipe dimension can be reduced to 10 mm minimum with the aim of an overall synchronization of (5 + 1) fs rms for the new broadband pickups. New developed EOMs will allow an amplitude modulation of the broadband pickup signal to the laser pulse.