A spill-resistant vessel has been developed for dispensing an alkali-metal vapor. Vapors of alkali metals (most commonly, cesium or rubidium, both of which melt at temperatures slightly above room temperature) are needed for atomic frequency standards, experiments in spectroscopy, and experiments in laser cooling. Although the present spill-resistant alkali-metal dispenser was originally intended for use in the low-gravity environment of outer space, it can also be used in normal Earth gravitation: indeed, its utility as a vapor source was confirmed by use of cesium in a ground apparatus.
The vessel is made of copper. It consists of an assembly of cylinders and flanges, shown in the figure. The uppermost cylinder is a fill tube. Initially, the vessel is evacuated, the alkali metal charge is distilled into the bottom of the vessel, and then the fill tube is pinched closed to form a vacuum seal.
The innermost cylinder serves as the outlet for the vapor, yet prevents spilling by protruding above the surface of the alkali metal, no matter which way or how far the vessel is tilted. In the event (unlikely in normal Earth gravitation) that any drops of molten alkali metal have been shaken loose by vibration and are floating freely, a mesh cap on top of the inner cylinder prevents the drops from drifting out with the vapor. Liquid containment of the equivalent of 1.2 grams of cesium was confirmed for all orientations with rubbing alcohol in one of the prototypes later used with cesium.
This work was done by William Klipstein of Caltech for NASA’s Jet Propulsion Laboratory. For further information, access the Technical Support Package (TSP) free online at www.techbriefs.com/tsp under the Physical Sciences category. NPO-40481
This Brief includes a Technical Support Package (TSP).
Spill-Resistant Alkali-Metal-Vapor Dispenser
(reference NPO-40481) is currently available for download from the TSP library.
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Overview
The document is a Technical Support Package for the Spill-Resistant Alkali-Metal-Vapor Dispenser, identified as NPO-40481, developed by NASA's Jet Propulsion Laboratory (JPL). It outlines the design and functionality of a "spill proof" cesium source prototype, which is crucial for experiments involving alkali metals, particularly cesium, in a controlled environment.
The design features a unique "tube in a tube" configuration that prevents spillage, ensuring that the cesium load does not contact the exit port regardless of the orientation of the device. This is particularly important in applications where precise control of vapor delivery is necessary, such as in cesium fountain experiments. The prototype includes a fine copper mesh that is spot-welded over the center tube, which serves to prevent droplets from migrating into the collection region. This design is complemented by a knife-edge vacuum gasket that enhances the overall integrity of the system.
The document emphasizes the proprietary nature of the information, indicating that it may contain sensitive data subject to export control regulations. Users are advised to comply with all applicable U.S. export regulations when handling the information.
The Technical Support Package is part of NASA's Commercial Technology Program, aimed at disseminating aerospace-related developments that have broader technological, scientific, or commercial applications. It encourages further exploration and utilization of the technology by providing contact information for the NASA Scientific and Technical Information (STI) Program Office, where additional resources and assistance can be obtained.
Overall, the document highlights the innovative engineering behind the Spill-Resistant Alkali-Metal-Vapor Dispenser, showcasing its potential applications in both scientific research and commercial technology. The advancements in this area reflect NASA's commitment to fostering innovation and collaboration in aerospace technology, with implications that extend beyond space exploration into various fields of research and industry.
