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.