Electron Beam Welding (EBW) is a fusion joining process that produces a weld by impinging a beam of high-energy electrons to heat the weld joint. Electrons are elementary atomic particles characterized by a negative charge and an extremely small mass. Raising electrons to a high-energy state by accelerating them to roughly 30 to 70 percent of the speed of light provides the energy to heat the weld. The electron beam is always generated in a high vacuum. The use of specially designed orifices separating a series of chambers at various levels of vacuum permits welding in medium and non-vacuum conditions.