Abstract: A process and device using back-diffusion for sampling a gas from an environment containing an aerosol of tramp material. The device cleans the tramp material from a barrier by the flow of a purge gas. The purge gas flow prevents diffusion of the tramp material through ports in the barrier through which the sample gas diffuses against purge gas flow. The purge gas continuously cleans the barrier, retards tramp material diffusion, and gathers and transports the sample gas.

Abstract: A calibration filament containing a sodium-bearing compound is included in combination with the sensing filament and ion collector plate of a sodium ionization detector to permit periodic generation of sodium atoms for the in-situ calibration of the detector.

Abstract: In a system employing flowing liquid metal as a heat transfer medium in contact with tubular members containing a working fluid, i.e., steam, liquid metal leaks through the wall of the tubular member are detected by dislodging the liquid metal compounds forming in the tubular member at the leak locations and subsequently transporting the dislodged compound in the form of an aerosol to a detector responsive to the liquid metal compound. In the application to a sodium cooled tubular member, the detector would consist of a sodium responsive device, such as a sodium ion detector.

Abstract: Variations in the conventional filament and collector electrodes of an alkali metal ionization detector, including the substitution of helical electrode configurations for either the conventional wire filament or flat plate collector; or, the substitution of a plurality of discrete filament electrodes providing an in situ capability for transferring from an operationally defective filament electrode to a previously unused filament electrode without removing the alkali metal ionization detector from the monitored environment.In particular, the helical collector arrangement which is coaxially disposed about the filament electrode, i.e. the thermal ionizer, provides an improved collection of positive ions developed by the filament electrode.

Abstract: An oxide coated filament exhibiting surface ionization and electron conductivity characteristics is employed in alkali metal ionization detectors to provide extended filament operating life.