Frequency shifts in NIST Cs Primary Frequency Standards due To Transverse RF Field Gradients

摘要

A single-particle Green's function (propagator) is introduced to study thedetection of laser-cooled Cesium atoms in an atomic fountain due to RF fieldgradients in the Ramsey TE011 cavity. The detection results in astate-dependent loss of atoms at apertures in the physics package, resulting ina frequency bias. A model accounting only for motion in one dimensiontransverse to the symmetry axis of the fountain is discussed in detail and thengeneralized to two transverse dimensions. Results for fractional frequencyshifts due to transverse field gradients are computed for NIST F-1 and F-2Cesium fountains. The shifts are found to be negligible except in cases ofhigher RF power applied to the cavities.