How Does the NIST-7 Atomic Clock Work?

The NIST-7 can be broken down into:

• Source of Cesium Atoms – in many energy states.
• Laser A – Puts atoms into the lowest energy state.
• Microwave Cavity – Microwaves at just the right frequency cause atoms to change to a higher, excited energy state.
• Frequency Divider – Converts the very high microwave frequency (about 9 billion cycles per second) to lower frequencies that are easier to use for counting.
• Servomechanism – Changes the frequency of the microwaves in the cavity to put the greatest number of atoms into the excited state, which results in the largest light signal on the detector.
• Laser B – Causes atoms in the excited state to emit light.
• Detector – Detects the emitted light.