A Pulsed Electron Beam System

A versatile and simplified electron beam system for producing variable duration pulses is described. The electron beam is swept over a narrow slit; the electrons passing through the slit fonn the variable duration pulse. A minimum pulse duration of 3 ns is theoretically possible with the present maximum sweep frequency of 1 Mc/s. However, the system should be adaptable with modification to accommodate higher sweep frequencies with a corresponding decrease in the pulse duration. Longer duration pulses, manually controlled single pulses, and repetitive pulses can be readily obtained. The electron beam is accelerated up to ground potential by a maximum accelerating potential of 60 kV. Beam currents up to 125 , ??A have been measured; however, beam currents considerably higher should be possible. Many of the components used in the system are commercially available.