![]() Vanier at Varian Associates in Beverly, Massachusetts, in collaboration with Professor Ramsey and Dr. NBS-2 is inaugurated in Boulder it can run for long periods unattended and is used to calibrate secondary standardsġ962, Robert Vessot and his associates, H. present the “Atomichron” (previously known as the NAFS), the first commercial atomic clockĩ,192,631,770 Hz value determined with the NPL standard by Essen and MarkowitzĬommercial cesium clocks become available, costing $20,000 eachġ959, NBS-1 goes into regular service as NIST's primary frequency standard.įirst atomic hydrogen maser was constructed by Goldenberg, Kleppner and Ramsey and its successful operation at Harvard as a free running oscillator was reported Natco’s (National Company’s) atomic beam clock, aka ABC, become known to be the National Atomic Frequency Standard or NAFSġ956, October, MIT, J. Although never operated as an atomic clock or used in a feedback loop with a stabilized oscillator, some say it is the first cesium-based atomic clock. William Markowitz’s (Director of Time Service of USNO) ET time scale. Louis Essen and Jack Parry of the National Physical Laboratory in England builds the first cesium-beam resonator used as a calibration source and determine a new value for the cesium hyperfine transition frequency based on the uniform time scale maintained by the Royal Greenwich Observatory, 9192.63183 MHz. Zach testifies at Oppenheimer’s AEC security hearing and negotiates agreement for commercial development of his atomic beam clock at the National Company Features:ĭevelopment of an efficient cesium beam sourceĭevelopment of "Stabilivac" titanium evapor-ion pump to permit operation of cesium atomic beam apparatus without cumbersome mechanical pump in combination with a diffusion pumpĭevelopment of electronic circuits to permit operation with a quartz oscillator "locked" to the cesium resonance Zacharias’s (“Zach”) cesium atomic beam frequency standard at MIT’s Molecular Beam Laboratory of the Research Laboratory of Electronics (originally the Radiation Laboratory) was put into operation, first to be in feedback loop with external oscillator (quartz) using a servo control system. NBS-1 is moved to NIST’s new laboratories in Boulder, Colorado.Īugust, first atomic beam clock (according to the IEEE): Professor Jerrold R. Dicke describes method for extending time of interaction of atomic particles with electromagnetic field by use of a selected gas to provide a medium in which diffusion limits the rate of movement of the active atomic particles (buffer gas) Professor Norman Ramsey invented the separated oscillatory field method of molecular beam magnetic resonance spectroscopyġ951, NIST completes the first direct measurement of the cesium hyperfine separation with the atomic beam technique with NBS-1ġ952, NIST completes the first accurate measurement of the frequency of the cesium hyperfine separation with NBS-1 (Lyons and his successor Polykarp Kusch and Jesse Sherwood)ġ953, Professor Robert H. Using Rabi’s technique, NIST (then the National Bureau of Standards) announces the world’s first atomic clock using the ammonia molecule as the source of vibrations made by Harold Lyons 1879, Lord Kelvin suggests idea of using atomic transitions to measure timeġ945, Isidor Rabi, a physics professor at Columbia University, suggests a clock could be made from a technique he developed in the 1930's called atomic beam magnetic resonance.
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