National Physical Laboratory

The Birth of Atomic Time - Essen's memoirs published

The Birth of Atomic Time - Ray Essex book cover

A new book has been published containing the memoirs of Louis Essen, celebrating 60 years since he built the world's first accurate atomic clock at the National Physical Laboratory (NPL).

In 1955, Louis Essen and Jack Parry designed and built the world's first caesium atomic clock at NPL, transforming the way we measure and use time. This was the first clock to keep time more accurately than the rotation of the Earth. Today, the caesium fountain atomic clock at NPL can measure time to an accuracy of one second in 158 million years

Published by Ray Essen, Louis' son-in-law, the book also includes a chapter written by NPL Fellow Patrick Gill on the future of atomic timekeeping.

Louis wrote his memoirs in 1996, and they provide a simple, non-technical account of his work, together with a few personal details. A more comprehensive account of the story of atomic timekeeping follows the memoirs, including previously unpublished material written by Louis in the 1950s.

The book is available to purchase on Amazon

Find out more about the 60th anniversary of the atomic clock

Find out more about NPL's work on Time & Frequency

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Last Updated: 26 May 2015
Created: 26 May 2015


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