Available to all scientists: the most accurate clock in the Netherlands

The signal provides time accuracy of just a few nanoseconds and frequency precision at the picosecond level – i.e. 0.000000000001 seconds. This enables certain types of research to be carried out with greater precision or in less time.

How the Dutch time and frequency network for research and education works

The SURF network is connected to VSL’s atomic clocks, which provide the Coordinated Universal Time scale (UTC) in the Netherlands. Using White Rabbit technology, this is converted into a White Rabbit signal with time accuracy of less than one nanosecond and frequency precision at the level of picoseconds. This technology was originally developed for high-precision signals in CERN’s particle accelerator. The White Rabbit equipment has been calibrated to achieve this accuracy.

At present, the SURF network offers this ultra-precise signal at 11 locations. Together, these form the Dutch time and frequency network for research and education. We expect the number of connected locations to grow further.

Working together towards a fully-fledged result 

The new SURF network service is multidisciplinary in nature and the result of multiple research collaborations. In addition to SURF, VSL and the White Rabbit Collaboration, 9 different universities and research institutes have been involved in its development over the past 15 years.

Step by step, major hurdles have been overcome, such as transporting time signals over long distances via fibre optics, combining time signals with “regular” network traffic on SURF’s production network, and validating the accuracy of the time signals. The history of SURF’s Time&Frequency service illustrates how groundbreaking multidisciplinary technologies can often only evolve into fully-fledged services through collaboration with experts and users from different domains.

Time savings and sharper observations 

Adding the VSL time and frequency signal to the network is an innovation that offers researchers many new opportunities. Think of scientific studies that can be carried out up to a hundred times faster and more accurately. For a PhD candidate, this can reduce months of work to just a few weeks. 

In addition, measurement instruments can perform far more precise and detailed measurements –for example, radio astronomy observations can become even sharper – and quantum communication equipment can be synchronised. This represents a major leap forward in research methods and the results they enable.

At the moment, the following research projects (among others) use the time and frequency signal via the SURF network:

• Precision measurements of the properties of elementary particles, atoms and molecules – VU
• Improvements to the White Rabbit protocol enabling countless atomic clocks in a network to work together as a virtual super atomic clock – VU
• Centimetre-accurate positioning based on mobile network signals and White Rabbit networks, for applications such as self-driving vehicles and drones – TU Delft
• Research into a perpetual atomic laser for building better atomic clocks – University of Amsterdam (UvA)
• Preparations for millimetre-level altitude measurements by measuring time delays caused by gravity using “quantum clocks” connected via fibre optics – UvA, VU
• A permanent comparison between VSL’s national atomic time in Delft and the atomic time of the European Space Agency (ESA) in Noordwijk