Decay properties of /sup 186/Pb and the lead alpha-decay rate anomaly

Conference · Sun Jan 01 04:00:00 EST 1984

OSTI ID:6192340

Toth, K S; Ellis-Akovali, Y A; Bingham, C R; Moltz, D M; Carter, H K; Mlekodaj, R L; Spejewski, E H; Sousa, D C

Alpha-decay transitions between ground states of doubly-even nuclei are taken to represent unhindered decays. Reduced widths for these s-wave transitions behave in a regular fashion as a function of both neutron and atomic number. They are largest for nuclei two or four particles beyond a closed shell (with sharp minima at the shell) and they then decrease as the next closure is approached. The s-wave widths for /sup 186/ /sup 188/ /sup 190/ /sup 192/Pb, however, have been reported to behave anomalously, i.e., they purportedly increase by a factor of 30 between /sup 186/Pb (N = 104) and /sup 192/Ob (N = 110) instead of decreasing as one nears N = 126. Theoretical calculations have not reproduced this unusual behavior. The (electron-capture (EC) + ..beta../sup +/) strengths were deduced from K x-ray intensities. A number of corrections are involved in such determinations. We undertook the investigation of the (EC + ..beta../sup +/) decay schemes of these neutron-deficient lead isotopes, in conjunction with studies of their ..cap alpha..-decay properties, to obtain more reliable ..cap alpha..-branching ratios. Herein we present new information on /sup 186/Pb and discuss the partial ..cap alpha.. half-lives for /sup 192/Pb, /sup 190/Pb, /sup 188/Pb, and /sup 186/Pb together with ..cap alpha..-decay rates for even-even nuclei with Z greater than or equal to 78.

• Research Organization: Oak Ridge National Lab., TN (USA); Tennessee Univ., Knoxville (USA); South Carolina Univ., Columbia (USA); UNISOR, Oak Ridge, TN (USA); Eastern Kentucky Univ., Richmond (USA)
• DOE Contract Number: AC05-84OR21400; AC05-76OR00033; AS05-76ER04936
• OSTI ID: 6192340
• Report Number(s): CONF-8409143-4; ON: DE85001115
• Country of Publication: United States
• Language: English

Related Subjects

651822* -- Nuclear Properties & Reactions
A=150-189
Experimental-- Radioactive Decay-- (-1987)
651922 -- Nuclear Properties & Reactions
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Experimental-- Radioactive Decay-- (-1987)
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ALPHA DECAY
ALPHA DECAY RADIOISOTOPES
BRANCHING RATIO
DATA
DECAY
EVEN-EVEN NUCLEI
EXPERIMENTAL DATA
HALF-LIFE
HEAVY NUCLEI
INFORMATION
ISOTOPES
LEAD 186
LEAD 188
LEAD 190
LEAD 192
LEAD ISOTOPES
NUCLEI
NUMERICAL DATA
RADIOISOTOPES
SECONDS LIVING RADIOISOTOPES