Intense, Nanosecond Electron Beams

Pulsed radiation sources of higher intensity and shorter duration are desired to broaden the scope of experimental studies of radiation-induced phenomena. For this purpose, a family of generators has been developed which can produce intense pulsed beams of electrons. The highly reproducible beam is extracted from the accelerating tube through a thin window and can be injected readily into other experimental apparatus. Available pulse durations range from 3 to 50 nanoseconds. The maximum electron energy can be adjusted continuously from 150 to 600 keV, or from 500 keV to 2 MeV, depending on the specific generator. Available peak beam currents range from 1,000 to 10,000 amperes, and the electron output can be varied from 1013 to 2 × 1015 electrons per pulse. When desired, the output beam can be concentrated magnetically to energy densities in excess of 100 cal/cm2, creating shock waves and permitting study of materials under intense transient stress. The basic design concepts, and diagnostic techniques developed or adapted for reliable measurement of the beam characteristics, will be discussed.