| 摘要 |
<p>The present invention relates to a focusing device for a beam of electrically charged particles, comprising a plurality of associated annular ring-shaped electrodes forming electrostatic lenses having a convergent resulting effect on the said beam on exit from a focusing head. It comprises at least one first and one second annular electrode (11, 12), situated in a body (9) of the device, and at least one third and one fourth annular electrode (13, 14) situated some distance from the body (9) in the said head (8), in that the said second electrode and the said third electrode are electrically interconnected by a high-voltage supply conductor tube (32), the said tube (32) being arranged longitudinally inside an outer tubular electrode (34) forming a mechanically strong envelope for the said head (8) and terminated by the fourth annular electrode (14) and in that the said third electrode (13) is formed by an inner conductive piece (33) which is linked in rigid and insulating manner with the said outer tubular electrode in the said head. <IMAGE></p> |
