NOTICE: Due to a lapse in annual appropriations, most of this website is not being updated. Learn more.

Form submissions will still be accepted but will not receive responses at this time. Sections of this site for programs using non-appropriated funds (such as NVLAP) or those that are excepted from the shutdown (such as CHIPS and NVD) will continue to be updated.

U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

PUBLICATIONS

The Evolution of Time Measurement: Part 3 - Atomic Clocks; The Evolution of Time Measurement: Part 4 - Atomic Second

Published

Author(s)

Michael A. Lombardi

Abstract

A historical article about the origins and the development ofatomic clocks and oscillators (Part III of a IV-part series). It describes the first atomic clock experiments, early laboratory and commercial cesium clocks, and the transition from astronomical to atomic timekeeping. It also describes cesium fountain clocks, the most accurate laboratory standards being used today.
Citation
IEEE Instrumentation and Measurement Magazine
Volume
15
Pub Type
Journals

Keywords

atomic time, cesium, clocks, frequency, time
Physics

Citation

Lombardi, M. (2012), The Evolution of Time Measurement: Part 3 - Atomic Clocks; The Evolution of Time Measurement: Part 4 - Atomic Second, IEEE Instrumentation and Measurement Magazine (Accessed October 24, 2025)

Issues

If you have any questions about this publication or are having problems accessing it, please contact [email protected].

Created February 1, 2012, Updated February 19, 2017
Was this page helpful?