Patent ID: 8120366

Claim:
A cold cathode ionization vacuum gauge comprising a rod-like first electrode and a pipe-like second electrode enclosing the first electrode and forming a discharge space between the first electrode and the second electrode, one end of the pipe-like second electrode being configured to be engaged in an airtight manner with a chamber to be measured, the gauge further comprising, a disc-like discharge trigger electrode plate disposed in the discharge space, wherein the rod-like first electrode passes through an aperture formed in the disc-like discharge trigger electrode plate and a plurality of projections which have tips directed toward the rod-like first electrode are provided at the periphery of the aperture, wherein the disc-like discharge trigger electrode plate is mounted in the discharge space with at least part of an outer periphery edge of the disc-like discharge trigger electrode plate pressed to the internal wall of the pipe-like second electrode, and wherein the disc-like discharge trigger electrode plate has elastic nails which project from the outer periphery of the disc-like discharge trigger electrode plate and the elastic nails are pressed to the internal wall of the pipe-like second electrode so as to mount the discharge trigger electrode plate in the discharge space.