photo of accelerator tube section[gif 89K] [jpeg 31K] A standard 333 KV NEC1 accelerator tube section. Three of these sections are grouped to form a 1 MV module.

plot of electric fields Calculated electrostatic fields[gif 5K]
Shaped and shorted electrodes at each end cause the z-axis fields to approach zero, resulting in transverse field components. The combination is intended to provide ion multiplication suppression.

plot of trajectories[gif 3K] Calculated beam trajectories - fortuitously, the field grading provides just the right amount of periodic focussing to transport a 2 Amp electron beam. The deceleration trajectories are essentially a mirror image. The 2 MV accelerator is identical accept the acceleration is terminated at the 2 MV level where the beam radius is 3.8 mm.

photo of accelerator module

Photo of a 1 MV section of the 2 MV accelerator showing support columns, charging chains, and decelerator tube surrounded by grading resistors.

[gif 174K][jpeg 62K]

1National Electrostatics Corp., Middleton, Wisconsin