Methods and apparatus for providing ultra-stable frequency standards and clocks

摘要

Improved clocks and frequency standards are provided through the use of single crystals having a mass of the order of kilograms maintained at temperatures of the orders of few degrees Kelvin which are caused to vibrate freely at low modes of resonant vibration. The frequency stability of such vibrations is ultra-stable over long periods of time and provide frequency standards and clocks having stability orders of magnitude greater than clocks and standards based upon quartz crystal oscillators and equal or better than standards and clocks based upon atomic beams (cesium, rubidium and hydrogen masers).