Low mass francium and emanation isotopes of high alpha stability /
By E. K. Hyde, A. Ghiorso [and] G. T. Seaborg.

Description

Main Author

Hyde, Earl K.

Related Names

Seaborg, Glenn T. (Glenn Theodore), 1912-1999.
Ghiorso, Albert.
Lawrence Radiation Laboratory.
U.S. Atomic Energy Commission.

Language(s)

English

Published

Berkeley, Ca. : [Lawrence] Radiation Laboratory, 1949.

Subjects

Francium.

Summary

Isotopes of francium with 126 or fewer neutrons have been looked for in bombardments of Th²³² with 350 Mev protons from the 184-inch cyclotron. Fr²¹² with an apparent half-life of 19.3 minutes for branching decay by alpha emission (44%) to At²©�⁸ and by orbital electron capture (56%) to Em²¹² has been found. Em²¹² is shown to be a 23-minute alpha-emitter. At²©�⁸ decays primarily (99.5%) by orbital electron capture to Po²©�⁸, but shows 0.5% alpha-branching. The francium and emanation isotopes have alpha half-lives completely out of line with the predictions based on the previously known isotopes of these elements. Their high alpha stability is believed to be due to a closed shell of 126 neutrons in analogy to the behavior of elements 83-85. The non-existence of long-lived francium in nature is discussed in the terms of this and other recent work on francium isotopes.

Note

"October 10, 1949."

Physical Description

14 p. : ill. ; 27 cm.

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