Nanosecond Pulsing for Van de Graaff Accelerators

A pulsed ion source capable of delivering 10-mA proton bursts with durations of approximately 1 nsec is described. Critical design constraints are discussed and used to illustrate the general procedure for meeting various experimental requirements. The system consists of a Duo-Plasmatron ion source, a lens-chopper combination, and a klystron buncher which uses the entire accelerator as a drift path to produce bunched ion bursts at the target. The equipment has been fitted into the terminal of the ORNL 3-MV Van de Graaff accelerator. Since no accessory bunching magnets are used, ion bursts can be delivered to many different target stations. An external diverter system is used to vary the repetition rate from 106 sec−1 down to 3×104 sec−1.