Energy of the 3/2{sup +} state of {sup 229}Th reexamined

Journal Article · Fri Apr 01 04:00:00 EST 2005 · Physical Review. C, Nuclear Physics

DOI:https://doi.org/10.1103/PhysRevC.71.044303· OSTI ID:20696049

Guimaraes-Filho, Z O; Helene, O ^[1]

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1. Instituto de Fisica, Universidade de Sao Paulo, CP 66318-CEP 05315-970, Sao Paulo (Brazil)

{sup 229}Th has an isomeric state of unusually low energy, whose adopted value is by now 3.5(10) eV. This value was determined indirectly, based on several very precise {gamma}-ray energies, between 25 and 217 keV, from the {alpha} decay of {sup 233}U. Two recent works suggest that the decay pattern of the transitions that link the low-energy levels of {sup 229}Th is different from that assumed in earlier works, but there also is a difference between them. In this article we investigate the effect on the value determined for the excitation energy of that isomeric state if those different assumptions regarding the {gamma}-ray transitions in {sup 229}Th are considered. We use published data and a statistical method that takes into account both variances and correlations between data. Adopting the statistically most acceptable assumption regarding the decay pattern of {sup 229}Th, we deduced the value of 5.5(10) eV for the excitation energy of that isomeric state, with consequences for both theoretical and experimental studies related to that level.

• OSTI ID: 20696049
• Journal Information: Physical Review. C, Nuclear Physics, Journal Name: Physical Review. C, Nuclear Physics Journal Issue: 4 Vol. 71; ISSN 0556-2813; ISSN PRVCAN
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ALPHA DECAY
CORRELATIONS
ENERGY LEVELS
EV RANGE
EXCITATION
GAMMA RADIATION
ISOMERIC NUCLEI
KEV RANGE
THORIUM 229
URANIUM 233