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DOE OSTI · 22443553

Nuclear Data Sheets for A = 129

Timar, Janos·Elekes, Zoltan·Singh, Balraj
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Abstract

The experimental nuclear spectroscopic data for known nuclides of mass number 129 (Ag, Cd, In, Sn, Sb, Te, I, Xe, Cs, Ba, La, Ce, Pr, Nd, Pm, Sm) have been evaluated and presented together with adopted properties for levels and γ rays. This evaluation represents a revision of the previous one 18 years ago by Y. Tendow (1996Te01). Extensive new data have become available for many nuclides in the intervening years, although, no data are available for excited states in {sup 129}Pm and {sup 129}Sm, and for {sup 129}Ag and {sup 129}Cd, only limited information is available for the g.s. and isomers. The decay schemes of {sup 129}Ag, {sup 129}Pm and {sup 129}Sm are unknown, and those for {sup 129}Cd, {sup 129}In, {sup 129}Ce, {sup 129}Pr and {sup 129}Nd are incomplete. Many γ rays and extended level schemes have been reported for the ground state and isomer decays of {sup 129}Ba to {sup 129}Cs, yet the adopted set of intensities in this evaluation originate from a brief paper in an annual laboratory report. There remain several unplaced gamma rays, coupled with ambiguity about division of intensities amongst the two activities of {sup 129}Ba with nearly the same half-lives. Isomerism is expected in {sup 129}Pr, but there is no confirmed identification. Low-lying level structure in {sup 129}Nd, including identification of a possible third long-lived isomer in this nuclide, remains uncertain. The spin-parity assignments of (5/2+) for the ground state and (7/2−) for an isomer at 107.6 keV in {sup 129}Ce are assigned based on strong support from systematics and band configurations, yet this result is in contradiction with the quadrupole interaction hyperfine structure measurement which favors 9/2− over 7/2− for the isomer, consequently 7/2+ for the ground state. Direct measurements of spins of ground state and isomer of {sup 129}Ce are needed to settle this issue. Confirmed spins and parities of the ground state and isomer of {sup 129}La are also lacking. Assignments in this work are mainly based on systematics of h{sub 11/2} decoupled structures. A direct measurement of ground state spin of {sup 129}La will also be desirable. Recommended data presented in this work supersede those in previous NDS evaluations of A=129 nuclides published by 1996Te01, 1983Ha46 and 1972Ho55.

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73 NUCLEAR PHYSICS AND RADIATION PHYSICSBARIUM 129CADMIUM 129CERIUM 129CESIUM 129EVALUATED DATAEXCITED STATESGAMMA RADIATIONGROUND STATESHALF-LIFEHYPERFINE STRUCTUREINDIUM 129ISOMERSLANTHANUM 129NEODYMIUM 129NUCLEAR DATA COLLECTIONSNUCLEAR DECAYPARITYPRASEODYMIUM 129PROMETHIUM 129SAMARIUM 129SILVER 129SPIN

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Timar, Janos, Elekes, Zoltan, Singh, Balraj. 2014-09-15. Nuclear Data Sheets for A = 129. https://doi.org/10.1016/j.nds.2014.09.002

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