Atomic clock
device · 1955 · Digital age
A clock paced by transitions in caesium atoms.
What it is made of
- Oscillator — has part. A quartz oscillator is tuned to the atoms.
- Cesium oven — has part. A source of the atomic beam.
- Microwave cavity — has part. It excites the 9.19 GHz transition.
- Atom detector — has part. It records the transitions.
Principles and materials it uses
- Caesium — is made of. Essen’s clock (1955) used a caesium atomic beam.
- Spectral lines — uses. The second is defined by the frequency of an atomic transition.
Where it is used
- GPS (satellite navigation) — is used in. The satellites carry atomic clocks; the position is calculated from signal arrival times.
- GLONASS — is used in. Atomic clocks.
History: what it evolved from and what it influenced
- Quartz clock — evolved from. The quartz oscillator is tuned to an atomic standard.