Blackbody radiation shift in primary frequency standards

Peter Rosenbusch,Andre Clairon,Shougang Zhang

doi:10.1109/freq.2007.4319241

Abstract

The principal coefficient k omicron for the blackbody radiation shift in primary frequency standards has been subject to discussion. We present extensive measurements of this shift performed on the SYRTE's atomic fountain clock, FO1. The DC Stark shift is measured at a range of electric fields reaching down to twice the rms ambient thermal field E 300 K - Furthermore, the blackbody radiation shift is measured directly by inserting a heated graphite tube around the atom trajectory. The Stark measurement reaches an accuracy of 2 x 10 -3 for the principal coefficient. The direct measurement gives an accuracy of 4%. Both results confirm our earlier measurement [Simon et alVhys. Rev. A 57 -- , 436 (1990)]. In the analysis a 3 x 10 -3 correction, due to a sign error in the theory must be made, so that the coefficient reads k omicron = -2.282(4) x 10 -10 Hz/(V/m) 2 .

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