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Type of Document	Dissertation
Author	Townes, Charles H.
URN	etd-10222002-094724
Persistent URL	http://resolver.caltech.edu/CaltechETD:etd-10222002-094724
Title	Concentration of the heavy isotope of carbon and measurement of its nuclear spin
Degree	PhD
Option	Physics
Advisory Committee	Advisor Name Title Unknown Committee Member
Keywords	None
Date of Defense	1939-01-01
Availability	unrestricted
Abstract NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document. Heavy carbon was concentrated with a Hertz diffusion apparatus to a maximum of 50%, and enough carbon at 30 to 40% concentration was obtained to make possible spectroscopic and nuclear disintegration work. The concentration was in two processes. Ordinary methane was let continuously through the light reservoir of a Hertz apparatus for the collection of a large quantity of gas containing 6 or 7% heavy methane, then this gas reintroduced into the system for a final concentration. Measurements on the C[superscript 13] - C[superscript 13] band spectrum show that the C[superscript 13] nucleus obeys Fermi-Dirac statistics and probably has a spin of 1/2. A 21 ft. grating and Lunmer-Gehrke plate combined were used to resolve the close [Lamda] type doublets of the O - O ([lamda] 5165) band of the C[superscript 13] - C[superscript 13] Swan system. Resolution was not complete, but was enough to determine the nuclear statistics and allow a good estimate of the spin. Further proposed work with the concentrated heavy carbon is outlined and some conclusions drawn from isotopic effects in an unidentified band which has hitherto been assigned to the carbon molecule.
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