Abstract
We report the results of a direct search for the () nuclear isomeric transition, performed by exposing -doped crystals to tunable vacuum-ultraviolet synchrotron radiation and observing any resulting fluorescence. We also use existing nuclear physics data to establish a range of possible transition strengths for the isomeric transition. We find no evidence for the thorium nuclear transition between 7.3 eV and 8.8 eV with transition lifetime (1–2) . This measurement excludes roughly half of the favored transition search area and can be used to direct future searches.
- Received 7 February 2015
DOI:https://doi.org/10.1103/PhysRevLett.114.253001
© 2015 American Physical Society