Results of a Direct Search Using Synchrotron Radiation for the Low-Energy (229)Th Nuclear Isomeric Transition.

@article{Jeet2015ResultsOA,
  title={Results of a Direct Search Using Synchrotron Radiation for the Low-Energy (229)Th Nuclear Isomeric Transition.},
  author={J. Jeet and Christian Schneider and Scott T. Sullivan and Wade G. Rellergert and Saed Mirzadeh and Arlete Cassanho and Hans P. Jenssen and E V Tkalya and Eric R. Hudson},
  journal={Physical review letters},
  year={2015},
  volume={114 25},
  pages={
          253001
        }
}
We report the results of a direct search for the (229)Th (I(π)=3/2(+)←5/2(+)) nuclear isomeric transition, performed by exposing (229)Th-doped LiSrAlF(6) 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) s… 

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This work is supported by the DARPA QuASAR program and the ARO under W911NF-11-1- 0369:P00004, NIST PMG, and DOE Office of Nuclear Physics, Isotope Program
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