The evaluation procedure of a new laser-cooled caesium fountain primary frequency standard developed at the National Institute of Standards and Technology (NIST) is described. The new standard, NIST-F1, is described in some detail and typical operational parameters are discussed. Systematic frequency biases for which corrections are made – second-order… (More)
We develop a comprehensive approach to the evaluation of the uncertainty of a primary frequency standard. Indirect, model-dependent means are employed for the evaluation of all known biases. This approach leads to a lower combined standard uncertainty (CSU) and leaves frequency measurements under altered conditions as a powerful search technique for unknown… (More)
INTRODUCTION NIST is currently investigating the design of a second-generation cesium-fountain primary frequency standard. The design goals of this standard include an ultimate frequency inaccuracy of δf/f < 10-16 and achievable stability better than σ y (τ) < 10-13 /τ 1/2. This standard is expected to eventually replace NIST-F1, the current U.S. primary… (More)
The presence of spurious spectral components in the microwave excitation may induce frequency shifts in an atomic fountain frequency standard. We discuss how such shifts behave as a function of power variations of the excitation carrier and in the spur-to-carrier ratio. The discussion here is limited to the case of single-sideband spurs, which are generally… (More)
Acknowledgements In retrospect I will consider my graduate career to be one of the most lively and exciting times of my life. It could be no less considering the contributions and support of so many outstanding colleagues. Dan Friedman and Kent Dybvig both supported me as advisors. Dan taught me to strive for clarity and simplicity without regard for… (More)
An optically pumped primary frequency standard is being constructed at the National Institute for Science and Technology. To achieve the potential accuracy of this new technology a thorough reconsideration of all the potential systematic errors has been undertaken. improved technologies (ovens and cavities), a unique beam tube has been designed and… (More)
† We show that the frequency bias caused by distributed cavity phase has a strong dependence on microwave power. We also show that frequency biases associated with microwave leakage have distinct signatures in their dependence on microwave power and the physical location of the leakage interaction with the atom.
The National Institute of Standards and Technology is developing an optically pumped, cesium-beam primary frequency standard. The design follows from an analysis of systematic errors found in cesium beam standards. The details of the design, performance of major subsystems, and preliminary tests of the standard are presented .
—Many high-performance atomic frequency standards , including cesium fountains and most optical standards, operate with pulsed measurements, that is, an atomic sample is prepared for measurement, the measurement is made, and the process is repeated at fixed intervals. By introducing frequency modulation of the excitation coherent with the measurement cycle… (More)