Atomichron®: The atomic clock from concept to commercial product

The first half of this paper (Sections I-III) gives an overview of the development of atomic clocks from the earliest suggestions that atoms could provide superlative frequency and time standards to the realization of a cesium-beam device (1955) capable of assuming this role in a national standards laboratory. The second half (Sections IV and V) describes in considerably greater detail J. R. Zacharias´ program of atomic beam clock development from its inception early in 1953 in MIT´s Research Laboratory of Electronics to its striking practical success late in 1956 in the National Company´s first commercial model.