학술논문
Improved Value for the Energy Splitting of the Ground-State Doublet in the Nucleus 229mTh
Document Type
Conference
Author
Source
Conference: Presented at: 12th International Conference on Nuclear Reaction Mechanisms, Varenna, Italy, Jun 15 - Jun 19, 2009
Subject
Language
English
Abstract
We have made an improved estimate of the {sup 229m}Th isomer energy. The new value, 7.8(5) eV, includes an estimate of possible spectral contamination effects due to the out-of-band E2 transition from the 42.43-keV 7/2+ member of the [633] ground state band to the 3/2+ [631] {sup 229m}Th bandhead and so a weak and unresolved transition a few eV different in energy. We estimate a 2% branching ratio for this unobserved transition in the 42.43-keV 7/2+ [633] deexcitation. The excitation of the {sup 229m}Th level is increased from the previously reported value of 7.6(5) eV to the new best value of 7.8(5) eV when this branch is included in the analysis.