公开(公告)号：US3852633A

公开(公告)日：1974-12-03

申请号：US31466072

申请日：1972-12-13

Applicant: VARIAN ASSOCIATES

Inventor： HUNTER G

IPC: H01J3/02 ,  H01J29/00

CPC classification number: H01J3/029

Abstract: The control grid structure for a convergent flow electron gun includes a corrective electrostatic lens associated with each of the beam passageways through the grid. The corrective electrostatic lenses increase in focusing strength taken from the outside of the beam toward the center of the beam to compensate for beamlet defocusing forces occasioned by the relatively large central aperture in the anode of the gun. In a preferred embodiment, the corrective electrostatic focusing lens structure comprises a second control grid portion interposed between a first control grid portion and the anode. The second control grid portion is thermally shielded from the cathode via the first grid portion for inhibiting unwanted thermionic emission from the composite control grid structure.

Abstract translation: 用于会聚流电子枪的控制栅格结构包括与通过栅格的每个束通道相关联的校正静电透镜。 矫正静电透镜增加聚焦强度从束的外部朝向光束的中心，以补偿由枪的阳极中较大的中心孔产生的小束散焦力。 在优选实施例中，矫正静电聚焦透镜结构包括介于第一控制栅格部分和阳极之间的第二控制栅格部分。 第二控制栅格部分经由第一栅格部分与阴极热屏蔽，用于抑制来自复合控制栅格结构的不期望的热离子发射。