ammonia clock

noun

Meaning

A timekeeping device that uses the frequency of electromagnetic radiation emitted by ammonia molecules during inversion to regulate its oscillator.

Examples

  • The ammonia clock developed at the National Bureau of Standards in 1949 represented a major leap in temporal accuracy.
  • Engineers found that the ammonia clock was highly sensitive to temperature fluctuations, which limited its long-term stability.

Synonyms: molecular clock, maser clock, atomic clock, frequency standard