Comment on "first accuracy evaluation of NIST-F2"

  title={Comment on "first accuracy evaluation of NIST-F2"},
  author={K. Gibble},
We discuss the treatment of the systematic frequency shifts due to microwave lensing and distributed cavity phase in Heavner et al 2014 Metrologia 51 174–82. We explain that the microwave lensing frequency shift is generally non-zero and finite in the limit of no applied microwave field. This systematic error was incorrectly treated and we find that it contributes a significant frequency offset. Accounting for this shift implies that the measured microwave amplitude dependence (e.g. due to… Expand
Measurement of the Microwave Lensing shift in NIST-F1 and NIST-F2
With several Primary Frequency Standards (PFS) across the world demonstrating systematic fractional frequency uncertainties on order of 1 x 10-16, it is crucial to accurately measure or model evenExpand
Reply to ``Comment on `Ramsey spectroscopy, matter-wave interferometry, and the microwave-lensing frequency shift' ''
The Comment by Jefferts et al. [Phys. Rev. A 91, 067601 (2015)] discusses the microwave-lensing frequency shift’s possible dependence on the initial wave-packet size and two effects of wallExpand
Microwave lensing frequency shift of the PHARAO laser-cooled microgravity atomic clock
We evaluate the microwave lensing frequency shift of the microgravity laser-cooled caesium clock PHARAO. We find microwave lensing frequency shifts of δν/ν = 11 × 10−17 to 13 × 10−17, larger than theExpand
Systematic Effects in Atomic Fountain Clocks
We describe recent advances in the accuracies of atomic fountain clocks. New rigorous treatments of the previously large systematic uncertainties, distributed cavity phase, microwave lensing, andExpand
Advances in the accuracy, stability, and reliability of the PTB primary fountain clocks.
Improvements of the systematic uncertainty, frequency instability, and long-term reliability of the two caesium fountain primary frequency standards CSF1 and CSF2 at PTB (Physikalisch-TechnischeExpand
Qualification and frequency accuracy of the space-based primary frequency standard PHARAO
The flight model of the laser cooled cesium atomic clock, PHARAO, has been qualified for operation in space. The clock has passed the vibration, thermal and electromagnetic compatibility testsExpand


Improved accuracy of the NPL-CsF2 primary frequency standard: evaluation of distributed cavity phase and microwave lensing frequency shifts
We evaluate the distributed cavity phase (DCP) and microwave lensing frequency shifts, which were the two largest sources of uncertainty for the NPL-CsF2 caesium fountain clock. We reportExpand
Comment on 'Accurate rubidium atomic fountain frequency standard'
We discuss the treatment of distributed cavity phase, microwave lensing and microwave leakage in the paper by Ovchinnikov and Marra (2011 Metrologia 48 87–100). The paper neglects the potentialExpand
Microwave leakage-induced frequency shifts in the primary frequency Standards NIST-F1 and IEN-CSF1
These uncontrolled stray fields are investigated here and it is shown that the frequency errors can be measured, and indeed even the location within the standard determined by the behavior of the measured frequency with respect to microwave power in the Ramsey cavity. Expand
Evaluating and minimizing distributed cavity phase errors in atomic clocks
We perform 3D finite element calculations of the fields in microwave cavities and analyse the distributed cavity phase (DCP) errors of atomic clocks that they produce. The fields of cylindricalExpand
First accuracy evaluation of NIST-F2
We report the first accuracy evaluation of NIST-F2, a second-generation laser-cooled caesium fountain primary standard developed at the National Institute of Standards and Technology (NIST) with aExpand
Distributed cavity phase frequency shifts of the caesium fountain PTB-CSF2
We evaluate the frequency error from distributed cavity phase in the caesium fountain clock PTB-CSF2 at the Physikalisch-Technische Bundesanstalt with a combination of frequency measurements and abExpand
Recoil Effects in Microwave Ramsey Spectroscopy
We present a theory of recoil effects in two zone Ramsey spectroscopy, particularly adapted to microwave frequency standards using laser cooled atoms. We describe the atoms by a statisticalExpand
Investigation of the distributed cavity phase shift in an atomic fountain
We report on measurements to characterize phase gradients inside the Cs microwave cavity in the SYRTE double fountain FO2. The clock frequency is measured as a function of the tilt of launch velocityExpand
Frequency shifts in NIST Cs Primary Frequency Standards due To Transverse RF Field Gradients
A single-particle Green’s function (propagator) is introduced to study the deflection of laser-cooled Cesium atoms in an atomic fountain due to RF field gradients in the Ramsey TE011 cavity. TheExpand
Evaluation of Doppler shifts to improve the accuracy of primary atomic fountain clocks.
Experimental verification of the finite element models of the cavities gives the first quantitative evaluation of this leading uncertainty and allows it to be reduced to δν/ν=±8.4×10(-17). Expand