Hitachi, Ltd.

Nobuo Hirano

Manabu Matsumoto

Toshiaki Kobari

Hiroaki Sakurabata

Mamoru Katane

Shiro Matsuzaki

An apparatus for treating the inner surface of a vacuum chamber includes a support, means for anchoring the vacuum chamber to the support and holding the vacuum chamber, a broach having a plurality of cutting edges having cutouts, and broach drive means to which the broach arranged on the support is fitted. The broach drive means unidirectionally moves the broach relatively to the vacuum chamber in an axial direction to cut off a contaminated layer on an inner surface of the vacuum chamber. The outer diameter of each cutting edge, excluding the cutouts, is set greater than that of an immediately preceding one in a direction of a rearmost edge face from a front edge face. The apparatus may also include means for supplying an inert gas or a mixture of nitrogen and inert gases to a surface of the vacuum chamber being treated by the broach, or means for supplying a lower alcohol for dissolving contaminants contained in the contaminated layer to the surface of the vacuum chamber being treated by the broach.

Apparatus for treating the inner surface of vacuum chamber

A rod driver is used to drive a rod so as to move a broach through a continuous vacuum chamber in the axial direction. The broach is provided at the leading end of the rod with cutting and finishing edges at a plurality of stages in the axial direction. The cutting edges each have chip breakers in their outer periphery. The broach is moved in the vacuum chamber to cut the inner surface of the vacuum chamber, so that a new surface is formed. During the cutting at least one of an inert gas, nitrogen, and a mixture of the inert gas and nitrogen is supplied to the cutting edges. The outer diameter of the finishing edge is same as the desired inner diameter of the vacuum chamber and the finishing edges are effective in forming such a vacuum chamber with greater precision and the least friction. As a contaminated and decomposed layer on the inner surface of the vacuum chamber is removed in the axial direction of the inner surface of the vacuum chamber for certain, moreover, gas desorption, from a new surface, originating from thermal desorption and photodesorption generated at the time of synchrotron radiation can be minimized to satisfy a requirement for a vacuum vessel.

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Ibaraki-ken, Japan

Nobuo Hirano