Inside
CERN's NA62 Experiment
For more than a decade, over 200 scientists from around the globe have joined forces in a single quest: to capture and observe ultra-rare particle decays and challenge the Standard Model of particle physics. Guided by the technical coordinator in charge of the overall integration of the experiment, we stepped into the heart of NA62, shortly before its operations drew to a close.
On a sunny late-winter morning, our host Hans Danielsson, drove us to CERN’s longest (270 m) experimental area in neighbouring France, the North Area, which houses the NA62 experiment.
With a PhD in physics, Hans left his native Sweden in 1989 to do research in quantum mechanics for his diploma work and to pursue his passion for physics at CERN, where he has spent his entire career. Starting on the ATLAS project, then dedicated to the NA62 experiment, his next and ultimate challenge may be the giant Future Circular Collider.
Working at CERN means balancing theory and engineering, in a deeply international and multidisciplinary culture. Physics does not happen only in equations, but also in high-tech equipment, cables, connectors, electronics, mechanical tolerances and crucial technical maintenance. This is why physicists work closely with multiple support groups, engineers, IT specialists and experts in applied physics, such as vacuum technologies, as well as industrial partners, all within the wonderful temple of collective intelligence that CERN is.
At the first stage of the NA62 experiment, also referred to as the “kaon factory”, long-lived particles are produced by sending extremely intense proton beams onto a stationary thin beryllium target, separated by a thick radiation-protection wall. This beam, extracted from the SPS (Super Proton Synchrotron particle accelerator/collider), produces almost one billion particles per second. About 6% of them are kaons that decay in many different ways. The experiment has been focusing on one particular type of extremely rare decay. More specifically, NA62 measures the rate at which a charged kaon decays into a charged pion and a neutrino-antineutrino pair.
To detect and study such ultra-rare kaon decays – 1 event in 10 billion decays – is like finding a needle in a haystack. Such unusual events happen only about twice a month(!) And when they do, they last approximately 200m (a split second) at the speed of light.
The NA62 Experiment, housed in North Area at CERN (IMAGE: CERN)
Particles are measured and filtered gradually as soon as they enter a large vacuum tank. First, a detector called CEDAR identifies the kaons in the beam from their emitted radiation. Their path is then determined by a silicon-pixel detector. Further detectors, such as a straw spectrometer, RICH and straw detectors, as well as the world’s most precise liquid krypton calorimeter, continue pursuing decay particles.
The NA62 detectors are distributed along 240 metres, matching the length over which the decay can take place. So, in the straight long experimental hall, everything is optimised for spotting particles that travel some distance before decaying.
Since we are intrigued by how detectors “see” particles that exist for only a fraction of a second, Hans explains: “Basically, by detecting “missing energy”.
Studying such rare kaon decays is scientifically fascinating because they verify some of the deepest questions in particle physics. Even though these decays occur extremely infrequently, they are precisely predicted by the Standard Model, making them exceptionally clean tests of fundamental physics. The experiment also allows researchers to detect unusual events and possible new particles that could help explain mysteries like dark matter.
never ever had an issue with LEMO connectors
Every connection is crucial
In ultra-rare event physics, such as the NA62 experiment, every signal matters.
And every signal begins with a reliable connection.
As we walked along the experimental hall, listening to Hans’ explanations about the experiment, wide-eyed and impressed, we spotted hundreds of LEMO connectors. Mostly high voltage and coaxial, S and the NIM-CAMAC 00 series. When asked about the requirements for such mission-critical connectors, Hans answered with a single word: “reliability”. And since his early days at CERN in 1989, he has “never ever had an issue with LEMO connectors.”
Why should society care about such highly complex research?
Because it delves into the building blocks of the universe, reaching into realms far from everyday experience, fundamental research may seem abstract, too complex and hard to understand for most people. Yet, the pursuit of rare kaon decays drives innovation in precision measurement, electronics reliability and data processing, technologies that eventually benefit society in unexpected ways. Technologies proven in such environments often find applications in medical imaging systems, cancer treatment, aerospace instrumentation, industrial measurement and high-speed communication systems, just to mention a few.
As Hans so accurately expressed it at the end of our visit, more than the practical applications, “It is in human nature to be curious and to seek answers to fundamental questions about the universe and matter. By creating models and understanding the infinitely small, we may one day come to understand the infinitely large.”
Article by Judit Hollos Spoerli, Corporate Communications Manager at LEMO
