Velocity Distribution Measurement of an Optically Pumped Cesium Frequency Standard at the NRLM

摘要

The velocity distributions of the optically pumped Cs frequency standard are measured using the rf pulse excitation method. The results are shifted toward higher beam velocity than the Maxwellian distribution and suggest a dependence on vacuum pressure. The velocity distribution is not sensitive to the laser power for pumping and detection, if the power is more than a few mW. The second-order Doppler shift was estimated as DELTA f = - 3.1 +/- 0.1 mHz.