Partial Separation of the Isotopes of Chlorine by Thermal Diffusion

The Clusius-Dickel isotope separator has been modified to allow larger scale separation of the isotopes of chlorine. The modified separator employs two coaxial Pyrex glass cylinders. A special design was necessary to allow for the heating and the resulting thermal expansion of the inner cylinder. The operation of the separator compares favorably with the operation predicted by the theory of Furry, Jones, and Onsager. The degree of isotope separation was determined directly by mass-spectrographic and spectrographic analyses. The concentration of ${\mathrm{Cl}}^{37}$ was also determined by measuring the amount of induced radioactivity resulting from deuteron bombardment of the sample to be analyzed. Sufficient chlorine gas containing 45 percent ${\mathrm{Cl}}^{37}$ was obtained for the determination by spectrographic means of the nuclear spin of ${\mathrm{Cl}}^{37}$.