Tool suitable for welding traveling wave tube waveguide bottom window needle assembly and welding method

A tool is suitable for fixing a traveling wave tube waveguide bottom window needle assembly to be welded, the tool comprises a base and a station used for containing a waveguide bottom and a window needle, the station comprises a containing groove arranged in the middle of the side surface of the base and configured to extend in the horizontal direction, and the containing groove is used for containing the waveguide bottom and the window needle. The lower wall surface of the accommodating groove is suitable for abutting against the lower part of the first-stage step so as to limit the vertical position of the waveguide bottom; the first limiting groove is formed in the side surface of the base below the accommodating groove, extends in the vertical direction and is suitable for being embedded with the protruding part so as to limit the horizontal position of the waveguide bottom; the second limiting groove is formed in the side surface, above the containing groove, of the base, is constructed to extend in the