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Concentration of the Heavy Isotope of Carbon and Measurement of its Nuclear Spin


Townes, Charles Hard (1939) Concentration of the Heavy Isotope of Carbon and Measurement of its Nuclear Spin. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/106Z-3X75.


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 C¹³ - C¹³ band spectrum show that the C¹³ 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 λ type doublets of the O - O (λ 5165) band of the C¹³ - C¹³ 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.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:Physics
Degree Grantor:California Institute of Technology
Division:Physics, Mathematics and Astronomy
Major Option:Physics
Awards:The Nobel Prize in Physics, 1964.
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Smythe, William Ralph
Group:Nobel Prize
Thesis Committee:
  • Unknown, Unknown
Defense Date:1 January 1939
Additional Information:The Nobel Prize in Physics 1964 was divided, one half awarded to Charles Hard Townes, the other half jointly to Nicolay Gennadiyevich Basov and Aleksandr Mikhailovich Prokhorov "for fundamental work in the field of quantum electronics, which has led to the construction of oscillators and amplifiers based on the maser-laser principle."
Record Number:CaltechETD:etd-10222002-094724
Persistent URL:
Related URLs:
URLURL TypeDescription Prize announcement (Physics, 1964)
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:4202
Deposited By: Imported from ETD-db
Deposited On:22 Oct 2002
Last Modified:06 Oct 2020 01:15

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PDF (Townes_ch_1939.pdf) - Final Version
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