Accuracy evaluation of NIST-F1

Abstract

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 Zeeman shift, black-body radiation shift, gravitational red shift and spin-exchange shiftare discussed in detail. Numerous other frequency shifts are evaluated, but are so small in this type of standard that corrections are not made for their effects. We also discuss comparisons of this standard both with local frequency standards and with standards at other national laboratories.

On the power dependence of extraneous microwave fields in atomic frequency standards

“…We have previously expanded the imaginary part of the field using a power series [22,15], which results in an expression such as…”

Lasers, Cold Atoms and Atomic Clocks: Realizing the Second Today

“…The first realizations were at the Standford University (Stephen Chu' group) and at the Paris Ecole Normale Superieure (C. Salomon group) [7,8]. Technology (NIST, Boulder Colorado), the Physikalisch-Technische Bundesanstalt (PTB, Braunschweig, Germany) and Istituto Nazionale Ricerca Metrologica (INRIM, Turin) [9][10][11]. Today, Cs fountains are also operated at the National Physical Laboratory in UK, and at the NICT and at the NMIJ in Japan.…”

NIST Cesium Fountains - Current Status and Future Prospects

“…This style of measurement, known as Ramsey interferometry, is used in all fountain frequency standards. Much more detailed information can be found in [1][2][3][4].…”

“…The shifts discussed above are a small subset of possible shifts. More complete discussions can be found in [2,3]. When all known possible shifts have been analyzed and/or measured, an accuracy budget is developed.…”