The Design, Construction, and Performance of a Cesium-Beam Tube

A discussion of salient aspects of the design, construction, and performance of the National Research Council 2.1-meter cesium-beam frequency standard is presented. Emphasis is placed on the characteristics of the cesium (F = 4)↔(F = 3) σ transitions as they are affected by a range of microwave power and weak dc-magnetic C-field intensities. The technique of C-field determination based on excitation of the (4,-4)↔(4,-3) transition is described.