Atomic time how does it work

Caesium atoms are evaporated in a furnace. Each atom can be in one of the two states of lowest energy that caesium atoms can assume. After evaporation the atoms are sorted by using a magnetic field so that only atoms in one particular state reach the cavity resonator. There the atoms are irradiated by a microwave field and stimulated to change their state. Dependent on the microwave frequency the probability for a state change is larger or smaller.

This definition refers to a caesium atom at rest at a temperature of 0 Kelvin. In an atomic clock, the natural oscillations of atoms act like the pendulum in a grandfather clock. However, atomic clocks are far more precise than conventional clocks because atomic oscillations have a much higher frequency and are much more stable. There are many different types of atomic clocks, but they generally share the same basic working principle, which is described below:.

First, the atoms are heated in an oven and bundled into a beam. Each atom has one of two possible energy states. They are referred to as hyperfine levels , but let's call them state A and state B. A magnetic field then removes all atoms in state B from the beam, so only atoms in state A remain. The state-A atoms are sent through a resonator where they are subjected to microwave radiation, which triggers some of the atoms to change to state B.

The more finely tuned the radio wave frequency is to 9,,, cycles per second, the more cesium atoms reach the detector. The detector feeds information back into the radio wave generator. It synchronizes the frequency of the radio waves with the peak number of cesium atoms striking it. Other electronics in the atomic clock count this frequency.

As with a single swing of the pendulum, a second is ticked off when the frequency count is met. The first quality atomic clocks made in the s were based on cesium, and such clocks honed to greater precisions over the decades remain the basis used to keep official time throughout the world. The NIST-F1 cesium atomic clock can produce a frequency so precise that its time error per day is about 0. Super-accurate timekeeping is integral to many elements of modern life, such as high-speed electronic communications, electrical grids and the Global Positioning System GPS and of course knowing when your favorite television show comes on.