Publication Date:
2016-05-07
Description:
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 (229)Th (denoted (229m)Th). 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 (229m)Th(2+). More precise determinations appear to be within reach, and would pave the way to the development of a nuclear frequency standard.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉von der Wense, Lars -- Seiferle, Benedict -- Laatiaoui, Mustapha -- Neumayr, Jurgen B -- Maier, Hans-Jorg -- Wirth, Hans-Friedrich -- Mokry, Christoph -- Runke, Jorg -- Eberhardt, Klaus -- Dullmann, Christoph E -- Trautmann, Norbert G -- Thirolf, Peter G -- England -- Nature. 2016 May 5;533(7601):47-51. doi: 10.1038/nature17669.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Ludwig-Maximilians-Universitat Munchen, 85748 Garching, Germany. ; GSI Helmholtzzentrum fur Schwerionenforschung GmbH, 64291 Darmstadt, Germany. ; Helmholtz-Institut Mainz, 55099 Mainz, Germany. ; Johannes Gutenberg-Universitat Mainz, 55099 Mainz, Germany.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/27147026" target="_blank"〉PubMed〈/a〉
Print ISSN:
0028-0836
Electronic ISSN:
1476-4687
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
,
Natural Sciences in General
,
Physics
