A Laser Triggered Synchronizable, Sub-Nanosecond Pulsed Electron Source

A laser excited, sub-nanosecond, pulsed electron beam system is described. The system consists of a high voltage pulser and a coaxial triggered spark gap. The liquid spark gap discharges into a pulse forming line designed to produce and maintain a flat voltage pulse of 1ns duration on the cathode of a photodiode. A synchronized laser is used to illuminate the photo-cathode to produce an electron beam with very high brightness, a short duration and with peak currents up to the space charge limit. The system can be configured to operate at energies from 1 MeV to 5 MeV and beam pulse widths from 10ps to 200ps with at least 10nC charge in the electron beam. Initial operating experience with a prototype system is discussed.