National Physical Laboratory

NPL named birthplace of atomic timekeeping

The National Physical Laboratory (NPL) has been officially declared the birthplace of atomic timekeeping by the European Physical Society (EPS). The announcement was made during a dedicated event at NPL in Teddington on 31 January 2014 and a plaque commemorating the historic occasion was unveiled.

A plaque was unveiled on 31 January 2014 to commemorate the construction of 'the first atomic clock to keep time better than the Earth's rotation' at NPL in 1955
A plaque was unveiled on 31 January 2014 to
commemorate the construction of 'the first atomic
clock to keep time better than the Earth's rotation'
at NPL in 1955.

The EPS Historic Sites Award recognises places in Europe that have made an exceptional contribution to physics. The award recognises NPL as the place where the first practical atomic clock was built, a landmark which has changed global timekeeping and made modern communications and location services possible.

In the 1950s, Louis Essen constructed the atomic clock, Caesium Mk. 1, with fellow physicist John Parry, at NPL. This new clock kept time more accurately than any other in existence and eventually paved the way for redefining the second in 1967, based on the fundamental properties of caesium atoms, rather than the Earth's rotation.

Professor John Dudley, President of the European Physical Society, said:

"Today NPL is justly recognised as a historic site. Essen's work here, as well as that of many other leading scientists, has benefitted the lives of all Europeans by providing the precision of timing required for applications such as advanced telecommunications, navigation and defence systems."

Dr Brian Bowsher, Managing Director of NPL, said:

"Being recognised by the EPS is an honour and is testament to the work of our current, as well as our past, scientists. Although invisible, atomic time has impacted the lives of all of us. What's more, ground-breaking developments continue to be made in this field, with a new generation of atomic clocks on the horizon that could provide everything from improved satellite navigation systems to more sensitive tests of fundamental physical theories."

NPL continues to provide a vital role in managing and distributing the UK's time. NPL's caesium fountain, NPL-CsF2, which is the reference for the national timescale UTC(NPL) is one of the most accurate clocks in the world, and is over 300,000 times more precise than Essen's clock from the 1950s.

NPL also carries out wide-ranging research in time and frequency measurement, which aims to improve timekeeping accuracy and its applications even further. A new service to provide time over optical fibre links to financial institutions, telecoms companies and other organisations that need accurate timing is currently being rolled out.

Atomic time affects us all every day. Each GPS satellite has atomic clocks on board that measure time very accurately in order to calculate global position, not only for providing directions but also for landing planes and precision farming, among many other applications. Atomic clocks synchronise every mobile phone network to manage the transfer from one cell to the next and atomic time is required to synchronise computer systems (for example, through the Network Time Protocol) to enable emails and other transactions online.

Watch videos of the talks from the event at NPL on 31 January 2014:

Download the booklet from the event Adobe Acrobat PDF file

View photos from the event on Flickr

More on NPL's History

More on NPL's work on Time & Frequency

For more information, please contact Fiona Auty

Last Updated: 12 Feb 2014
Created: 30 Jan 2014

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