END PLATE UNIT

To realize an end plate structure which closes an opening end of a vacuum duct easily at low costs.SOLUTION: An end plate unit 1 includes: a first flange 10 having an attachment surface 20 to be attached to an opening end of a vacuum duct 104 and having an annular or frame-like shape; a seal housing part 24 which is provided on a seal surface 22 located on an opposite side surface of the attachment surface 20 in the first flange 10 so as to enclose an opening end of the first flange 10; a metallic seal member 26 which is fitted in the seal housing part 24; an end plate 12 which is attached to the seal surface 22 so as to place the seal member 26 therebetween to close the opening end of the first flange 10 and yet allows charged particles to penetrate; a second flange 14 which sandwiches the end plate 12 with the first flange 10; and fastening members 30 each of which fastens a radial outer position of the seal member 26 on facing surfaces of the first flange 10 and the second flange 14 in an axial direction.SELECTED DRAWING: Figure 2 【課題】真空ダクトの開口端を閉止する端板構造を簡易かつ低コストに実現する。【解決手段】端板ユニット１は、真空ダクト１０４の開口端に取り付けられる取付面２０を有する環状又は枠状の第１フランジ１０と、第１フランジ１０における取付面２０とは反対側面に位置するシール面２２に、第１フランジ１０の開口端を取り囲むように設けられたシール収容部２４と、シール収容部２４に嵌着される金属製のシール部材２６と、シール部材２６を間に介装するようにシール面２２に取り付けられて第１フランジ１０の開口端を閉止する一方、荷電粒子が透過可能な端板１２と、第１フランジ１０との間に端板１２を挟持する第２フランジ１４と、第１フランジ１０と第２フランジ１４との対向面におけるシール部材２６よりも半径方向外側位置を軸線方向に締結する締結部材３０と、を備える。【選択図】図２