ELECTRON LINEAR-ACCELERATOR BASED ON THE CROSSED-WAVE ELECTRIC AND STATIC MAGNETIC-FIELD

A new type of linear electron accelerator, based on the crossed-wave-e lectric field and static magnetic field system known as the upsilon(p) x B acceleration mechanism observed originally in plasma, has been de monstrated in vacuum for the first time. In this scheme a static magne tic field is applied vertically to direction of the wave propagation a nd the particles are accelerated along the wavefront in a constant pha se with respect to the wave. The present machine can be either a conve ntional linear accelerator or a new type of upsilon(p) x B accelerator without any modification. An energy gain of 12.8 keV for electrons is observed from an incident energy of 66 keV in a 0.5 m accelerator, wh en an external magnetic field of 2.5 G is applied. The energy gain is 30% higher than that of conventional linacs. The energy gain is propor tional to the square of the applied magnetic field strength B0 as long as the electrons are trapped within a wave trough. Experiments have b een carried out with two different RF power levels in order to confirm the trapping condition for electrons, which depends on both the elect ric field and the applied magnetic field. The results of experiments a nd theories are in fairly good agreement.