The Concentration of the Isotope Helium 3

Citation

Andrew, Alan (1949) The Concentration of the Isotope Helium 3. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/3k2f-hm28. https://resolver.caltech.edu/CaltechTHESIS:05302025-145454726

Abstract

The isotope He³ was concentrated a factor of 10⁵ times in a two stage apparatus. The first stage of the apparatus consists of five Clusius-Dickel Thermal Diffusion Columns, and the second stage is a twenty-nine unit Hertz Apparatus.

Gas well helium flowed continually through the Clusius-Dickel stage, but the product was removed only every eight days. This product was then introduced to the Hertz Apparatus in daily amounts. As the final concentration is linear with time, the product of the Hertz Apparatus was removed as the need demanded. A seven day product had a ratio of 0.008 of He³ /He⁴ as measured by a mass spectrograph. Another seven day product was used to fill a discharge tube. The isotopic shift of λ 6678 was resolved by two methods: (1) 15 ft. Rowland mounting and (2) Fabry-Perot Interferometer. The calculated and observed shifts agree within the experimental error.

A table of performance ratings with other isotopic mixtures for the Clusius-Dickel Columns is given, as well as the experime11tal results of the separation of two different mixtures of gases: CO₂ and N₂, and CO₂ and He.

The separation factor for a three component mixture in the Clusius-Dickel Columns is derived.

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