Direct detection of the Th-229 nuclear clock transition

作者：von der Wense Lars; Seiferle Benedict; Laatiaoui Mustapha; Neumayr Juergen B; Maier Hans Joerg; Wirth Hans Friedrich; Mokry Christoph; Runke Joerg; Eberhardt Klaus; Duellmann Christoph E; Trautmann Norbert G; Thirolf Peter G

来源：Nature, 2016, 533(7601): 47-+.

DOI：10.1038/nature17669

Today's most precise time and frequency measurements are performed with optical atomic clocks. However, it has been proposed that they could potentially be outperformed by a nuclear clock, which employs a nuclear transition instead of an atomic shell transition. There is only one known nuclear state that could serve as a nuclear clock using currently available technology, namely, the isomeric first excited state of Th-229 (denoted Th-229m). Here we report the direct detection of this nuclear state, which is further confirmation of the existence of the isomer and lays the foundation for precise studies of its decay parameters. On the basis of this direct detection, the isomeric energy is constrained to between 6.3 and 18.3 electronvolts, and the half-life is found to be longer than 60 seconds for Th-229m(2+). More precise determinations appear to be within reach, and would pave the way to the development of a nuclear frequency standard.

• 出版日期2016-5-5