An electromechanical device operating at high voltage (125-l30,000 volts DC) which focuses a beam of high-energy deuterons on a target surface containing tritium. Nuclear fusion of the deuteron ions and target atoms produces high-energy (14-MeV) neutrons. The neutron radiation can be controlled in precise cyclic bursts or pulses, with time in between pulses for the measurement of induced-radioactivity and decay-time schemes.