National Institute for Subatomic Physics

What are neutrinos?

Neutrinos are subatomic particles without charge. They have virtually no mass. Neutrinos have a very weak interaction with matter and are therefore very difficult to detect. They can even fly through the earth ‘unscathed’ and come out at the other side.

What does the research entail?

To study neutrinos, the researchers need a very big telescope. ANTARES is a neutrino telescope positioned 40 km from the coast of Toulon, France, on the sea bed 2500 meter below sea level. The objective of ANTARES is to study neutrinos that have their origin in the cosmos.  These neutrinos have a high energy (from 1010 until 1017 eV and maybe even above that). 

To observe more far-off neutrino sources  the researchers need an even bigger neutrino telescope than ANTARES. For this, a project has been started, known as KM3NeT. The aim is to develop a neutrino telescope measuring more than a cubic kilometer.

How do the researchers know they are dealing with neutrinos?

The detector’s location on the sea bed has been chosen because only neutrinos can go through the earth without being hindered by other particles. Cosmic neutrinos will every now and then collide with the water around the telescope or the matter in the sea bed. When that happens, electrically charged neutrinos are produced that move in practically the same direction as the neutrino. Such a muon produces light as it moves through the sea water. We call this Cerenkov radiation. The ANTARES telescope detects this light using 900 photon tubes (electron tubes with which very weak light signals can be detected). 

What is Nikhef's contribution to the project?

Nikhef has developed an advanced read-out system for the ANTARES neutrino telescope. Apart from that, Nikhef has developed an electrical power network together with the Dutch industry. The Dutch team also contributes to the analysis of the measurement data.

Why do we want to know this and what are the possible applications?

Fundamental physics researchers aim to gather basic knowledge of everything around us. There are many things we already know thanks to fundamental research, such as that all matter known to us is built up of atoms, but there are still many unanswered questions. To put all the puzzle pieces together, we need fundamental research, carried out by curious scientists.

Detecting and studying neutrinos is important to gain a better understanding of the behaviour of neutrinos. However, neutrinos can also be used to study far-off astrophysical objects. This way, the researchers hope to learn where cosmic radiation comes from and how particle accelerators in the universe work. 

Websites of the research collaborations

ANTARES 
KM3NeT