A three-dimensional model of the gas cell atomic frequency standard

Initial calculations from a three-dimensional (3-D) model of the gas cell atomic frequency standard are discussed. In particular, a recent suggestion that the short-term stability of a gas cell standard might be improved by varying the microwave power is considered. Though the authors´ results generally support the previous conclusion, they show that the degree of sensitivity is less than that predicted by one-dimensional (1-D) gas-cell frequency-standard model. This difference in predicted sensitivity is a manifestation of the three-dimensional model´s more accurate treatment of the clock-cavity microwave field distribution. The more accurate treatment is highlighted by the three-dimensional model´s determination of isoefficiency contours (contours showing spatial regions in the clock cavity that have equal efficiency for producing clock signal), and noting their spatial dependence on microwave power.<>