This locked frequency is then divided by 9,192,631,770 to give the familiar one pulse per second required by the real world. This peak is then used to make the slight correction necessary to bring the crystal oscillator and hence the microwave field exactly on frequency. A detector at the end of the tube gives an output proportional to the number of cesium atoms striking it, and therefore peaks in output when the microwave frequency is exactly correct. When a cesium atom receives microwave energy at exactly the right frequency, it changes its energy state.Īt the far end of the tube, another magnetic field separates out the atoms that have changed their energy state if the microwave field was at exactly the correct frequency. An MIT-designed atomic clock uses entangled atoms to keep time even more precisely than its state-of-the-art counterparts. Our state-of-the-art facilities manufacture cesium. As optically pumped Cesium-beam frequency standard, the PCAC1000 has the high frequency accuracy and. The range of the microwave generator is already close to this exact frequency, as it comes from an accurate crystal oscillator. Our cesium time and frequency references are the most accurate commercial atomic clocks available. Optically-Pumped Caesium Atomic Clock PCAC1000. These clocks feature high-performance cesium beam tubes, with accuracy 1 part in 1012, frequency stability 8 parts in 1014, and a time domain stability of < 2 parts in 1014 with an averaging time of 5 days. Well turn it on and play with it, of course, but Ill also explain h. The cesium beam clocks used at USNO are commercial rack-mounted devices. The frequency of the microwave energy sweeps backward and forward within a narrow range of frequencies, so that at some point in each cycle it crosses the frequency of exactly 9,192,631,770 Hertz (Hz, or cycles per second). I finally get my hands on what I consider a holy instrument: the HP 5061A Cesium clock. First they pass through a magnetic field that selects atoms of the right energy state then they pass through an intense microwave field. To create a clock, cesium is first heated so that atoms boil off and pass down a tube maintained at a high vacuum.
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