Chamber for an ionization vacuum gauge

A chamber (11, 12, 13) for bounding a plasma generation area (42) in a vacuum pressure sensor (40), wherein the chamber comprises an electrically conductive casing element (1, 1′, 1″) located radially on an outside relative to a central axis (A), wherein the chamber comprises electrically conductive wall elements (2, 2′, 2″) arranged substantially perpendicular to the central axis and connected to the electrically conductive casing element, wherein at least one of the wall elements has a first opening (3), through which the central axis (A) extends, wherein the electrically conductive casing element comprises at least a first (B1) and a second region (B2), wherein the first region is located closer to the central axis than the second region, and wherein the electrically conductive casing element is conical at least in part.