Collaboration with UZH: New Fundamental Physics Laboratory at the BedrettoLab

What’s the reason you want to do research in such a remote place like the BedrettoLab?

The physics laboratory we want to establish in the BedrettoLab is an extension of our own labs. One of the key challenges we face in particle physics is radioactivity coming from the atmosphere. You have to imagine that there is a constant rain of muons, particles that are part of cosmic radiation, permeating everything: our bodies, buildings, equipment. Muons can interact with materials and create background radiation through various secondary effects, such as spallation or neutron production. When you search for dark matter, the instruments you use are extremely sensitive to this kind of radiation. Therefore, you need to find places that shield you from it. That’s the main reason why much of our research and development happens in underground facilities, not just the experiments themselves, but also the building and testing of our instruments.
The BedrettoLab is perfect for this. It’s just a two hours journey from Zurich and therefore easily accessible. With around 1.5 km of granite above us, we’re shielded from most cosmic radiation. Plus, the lab is already well-equipped, which gives us a great starting point.

One of your major research topics is dark matter. Can you briefly explain what dark matter actually is?

What we know from astronomical and astrophysical observations is that there’s about five times more matter in the universe than we can actually see. That means most of the matter in the universe is invisible, we can’t see or touch it, but we know it’s there because of how its gravity affects stars and galaxies.
The behavior of dark matter suggests it should be a new kind of particle, but we haven’t directly detected it yet. And we don’t yet know its mass.
What we’re hoping to detect with our instruments is a collision between a dark matter particle and regular matter. Such a collision would produce a tiny flash of light and/or charge that our special detectors could measure.

Do you expect to detect such a collision once your equipment is set up in the BedrettoLab?

Detecting such a collision there is unlikely, simply because it would require very large particle detectors. What we plan to do in the BedrettoLab is to develop new techniques that we’ll later use in larger detectors and to perform measurements shielded from cosmic rays that helps us to improve our detectors. That said, our long-term vision for the BedrettoLab does include equipment that could, in principle, detect particles such as dark matter.

Can you explain your plans for developing fundamental physics research in the BedrettoLab?

We’ve already started our first measurements in the BedrettoLab to understand the environment there in terms of fundamental physics. This includes detecting radiation fields, electromagnetic interference, and vibrations. For the vibrations, we’re using data from the seismological instruments already in place.
The next step is to build a cleanroom in the cavern at tunnel meter 3,500. This cleanroom will open up several possibilities for experiments in fundamental physics. In the first phase, we’ll install a high-purity radiation counter to measure and screen materials for use in dark matter and neutrino detectors, perform precise isotope analysis, and that also can be used to examine the radioactive content of soil and water samples.
Later on, we’d like to add a dilution refrigerator. This device would allow us to detect potentially  dark matter even without large-scale equipment. It operates at temperatures close to absolute zero and is thus able to operate ultra-sensitive quantum sensors, which can detect tiny signals from rare particles.
A dilution refrigerator like this is rare in underground laboratories, so that would be quite special. Overall, I’m really impressed with the BedrettoLab and very optimistic about building a unique laboratory for fundamental physics there.

More info about Björn Penning's research at the BedrettoLab can be found here.