Pressurized ionization chamber

The pressurized ionization chamber has a pressure-resisting cylindrical casing, connected to ground potential, as well as a cylindrical potential electrode, arranged coaxially to it, and a measuring electrode in the shape of a closed hollow cylinder. This pressurized ionization chamber is mounted to process lines in the open air or near hot material to be measured. It is thus submitted to changes of the outside temperature of e.g. 30K in a very short time. In order to eliminate the dependence of the ioniztion chamber current on these temperature variations, the chamber volume contributing to the result of the measurement is limited to narrow interspaces between the measuring electrode and the wall of the casing. The pressurized ionization chamber has practically got no clearance volume. (DG)