Absolute frequency measurement at 10-16 level based on the international atomic time

8th Symposium on Frequency Standards and Metrology 2015

Hachisu, H.^1 ; Fujieda, M.^1 ; Kumagai, M.^1 ; Ido, T.^1

Space-Time Standards Laboratory, National Institute of Information and Communications Technology (NICT), Tokyo, Koganei

184-8795, Japan^1

关键词: Absolute frequency;    Absolute frequency measurements;    Consecutive measurements;    Intermittent measurements;    International Atomic Time;    International atomic time (TAI);    Optical frequency standard;    Systematic uncertainties;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/723/1/012042/pdf
DOI  :  10.1088/1742-6596/723/1/012042

来源: IOP

【 摘 要 】

Referring to International Atomic Time (TAI), we measured the absolute frequency of the87Sr lattice clock with its uncertainty of 1.1 x 10-15. Unless an optical clock is continuously operated for the five days of the TAI grid, it is required to evaluate dead time uncertainty in order to use the available five-day average of the local frequency reference. We homogeneously distributed intermittent measurements over the five-day grid of TAI, by which the dead time uncertainty was reduced to low 10-16level. Three campaigns of the five (or four)-day consecutive measurements have resulted in the absolute frequency of the87Sr clock transition of 429 228 004 229 872.85 (47) Hz, where the systematic uncertainty of the87Sr optical frequency standard amounts to 8.6 x 10-17.