LIMITING MIGRATION OF TARGET MATERIAL

摘要

In an electron irradiation system, a gas-tight housing encloses a cathode region and an irradiation region, which communicate through at least an aperture. In the cathode region, there is arranged a high-voltage cathode for emitting an electron beam. In the irradiation region, there is an irradiation site arranged to accommodate a stationary or moving object to be irradiated. The migration of cathode-degrading debris is limited by means of an electric field designed to prevent positively charged particles from entering the cathode region via the aperture. The invention can be embodied with an axial electric field, which realizes an energy threshold, or a transversal field which deflects charged particles away from trajectories leading into the cathode region.

主权项

1. An electron irradiation system comprising:
a first conductive element; a gas-tight housing comprising said first conductive element which is electrically connected to at least a portion of the housing, the housing enclosing a cathode region and an irradiation region communicating with the cathode region; a high-voltage cathode, which is arranged in the cathode region and operable to emit an electron beam; an irradiation site, which is arranged in the irradiation region; and an aperture connecting the cathode region and the irradiation region and enclosing an electron trajectory from the cathode to the irradiation site, and a second conductive element and a voltage source for applying a nonzero bias voltage between the first and second conductive elements, for thereby generating an electric field (E) which prevents positively charged particles from entering the cathode region via the aperture.