Linear accelerator

A linear accelerator exhibiting an extremely low level of energy dispersion is disclosed essentially comprising a particle source, a main accelerator section and a pre-setting accelerator section disposed prior to the main accelerator section for controlling the energy of a particle emitted from the source with respect to a given phase angle. As there is virtually no drift space between the pre-setting and main accelerator sections, particles are directly received by the main accelerator section after having been emitted at a constant energy from the source and corrected by the pre-setting accelerator section so as to attain a previously established energy and phase angle. The final energy exhibited by the emitted particles is extremely uniform within a certain range of phase angles, thus producing particle beams with wide applicability in electron microscopes as well as diffraction and x-ray devices. (Owens, K.J.)