atomic clockArticle Free Pass atomic clock, type of clock that
uses certain resonance frequencies of atoms (usually cesium or
rubidium) to keep time with extreme accuracy. The electronic
components of atomic clocks are regulated by the frequency of
the microwave electromagnetic radiation. Only when this
radiation is maintained at a highly specific frequency will it
induce the quantum transition (energy change) of the cesium or
rubidium atoms. In an atomic clock these quantum transitions are
observed and maintained in a feedback loop that trims the
frequency of the electromagnetic radiation; like the recurrent
events in other types of clocks, these waves are then counted.
In 1967 the 13th General Conference on Weights and Measures
redefined the second, the unit of time in the International
System of Units, in terms of the cesium standard so as to equal
the second of Ephemeris Time. The conference defined the second
as “the duration of 9,192,631,770 periods of the radiation
corresponding to the transition betwe