Inventors:
Volker Stieber - Walnut Creek CA
Franz Krispel - Walnut Creek CA
Assignee:
Siemens Medical Laboratories, Inc. - Walnut Creek CA
International Classification:
G21K 108
Abstract:
A method and an apparatus for irradiating a relatively large area with a charged particle beam. In the method, a pencil-like beam is generated and spread along a fan axis perpendicular to the beam axis. The fan axis is rotated around the beam axis so that finally a circular area is irradiated. The apparatus includes means for generating a pencil-like beam, a lens system for spreading the beam along the fan axis and means to rotate the fan axis around the beam axis. In a preferred embodiment, the beam is spread such that its transverse intensity distribution increases with increasing distance from the beam center so that the area swept by the beam is irradiated with an even intensity.