公开(公告)号：US3832596A

公开(公告)日：1974-08-27

申请号：US35106573

申请日：1973-04-13

Applicant: VARIAN ASSOCIATES

Inventor： NELSON R ,  LIEN E ,  MIRAM G

IPC: H01J23/087 ,  H01J23/065 ,  H01J25/34

CPC classification number: H01J23/065

Abstract: A high convergence magnetically focused linear beam tube includes a pair of magnetic pole piece structures at opposite ends of the interaction circuit. At least one of the magnetic pole piece structures includes a centrally apertured transverse wall and an axial tubular projection extending away from the transverse wall for shaping the magnetic field externally of the region of the interaction circuit. The diameter of the central aperture is predominantly determinative of the gradient of the convergent axial magnetic field in the high field region, i.e., greater than 50 percent of the maximum axial magnetic field especially in the region of the beam near the beam minimum. The beam aperture is surrounded by a non-magnetic gap in the pole piece structure for independently controlling a certain amount of leakage of magnetic field through the pole piece structure to predominantly determine the magnitude of the axial magnetic field in the low field region, i.e., less than 10 percent of the maximum axial magnetic field intensity externally of the interaction circuit. Controlling the gap width is useful in the case of permanent magnet focusing for moving the point of magnetic field reversal away from the interaction circuit at either the collector or cathode end of the tube to obtain a desired shape of the magnetic flux divergence or convergence.

Abstract translation: 高收敛磁聚焦线性束管包括在相互作用电路的相对端的一对磁极片结构。 磁极片结构中的至少一个包括中心有孔的横向壁和远离横向壁延伸的轴向管状突起，用于使相互作用电路的区域外部的磁场成形。 中心孔的直径主要决定于高场区域中的会聚轴向磁场的梯度，即大于最大轴向磁场的50％，特别是在光束最近的波束区域。 光束孔径被极片结构中的非磁隙包围，用于独立地通过极片结构控制一定量的磁场泄漏，以主要确定低场区域中的轴向磁场的大小，即， 小于相互作用电路外部最大轴向磁场强度的10％。 控制间隙宽度在永磁体聚焦的情况下是有用的，用于在管的集电极或阴极端处使磁场反转远离相互作用电路，以获得磁通发散或收敛的期望形状。