cesium-beam atomic clock

cesium-beam atomic clock

[′sē·zē·əm ‚bēm ə′täm·ik ′kläk]
(nucleonics)
An instrument, used as the primary standard of frequency and time, in which a microwave oscillator, which generates radiation in a microwave cavity, is maintained at a frequency such that a hyperfine transition is induced in cesium atoms in a beam passing through the cavity. Also known as cesium-beam atomic oscillator.