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The Eight New Synthetic Elements

Description: No Description Available.
Date: November 1, 1947
Creator: Seaborg, Glenn T.
Partner: UNT Libraries Government Documents Department

The Eight New Synthetic Elements

Description: In an early continuation of the investigation of the radioactive isotopes of element number 43 (technetium) Segre and Seaborg produced by the deuteron and neutron bombardment of molybdenum the isotope Tc{sup 99}, which they observed to decay by means of an isomeric transition with a half-life of 6.6 hours to a lower isomeric state with a half-life greater than 40 years. The upper isomeric state of this isotope was observed by Segre and C. S. Wu to be produced in the fission of uranium and more recently R. P. Schumann and also D. C. Lincoln and W. H Sullivan working on the Plutonium Project of the Manhattan District have independently observed the beta-particles of half-life about 10 years due to the lower isomeric state. Later work by E. E. Motta and G. E. Boyd sets a more accurate value of 9.4 x 10{sup 5} years for this half-life. Since this isotope is formed in rather large amounts, namely, a fission yield of 6.2%, in the slow neutron induced fission of uranium it is now possible to isolate technetium in weighable amounts and in rather substantial quantities. For example, a uranium pile operating at a power level of 10{sup 5} kw would produce about four grams of technetium, as the isotope T{sup 99}, per day. With such a long half-life the radioactivity associated with convenient amounts (some mg.) would be so small in intensity as to not create a problem provided reasonable care in handling were exercised.
Date: November 1, 1947
Creator: Seaborg, Glenn T.
Partner: UNT Libraries Government Documents Department