Neutrino research below zero

It can be challenging to work if it's below zero. At the South Pole it's about -30°C in the summer and -60°C in the winter. How do you conduct research in severe cold? Chad Finley is an associate professor at Fysikum and member of the international collaboration that operates the IceCube Neutrino Observatory at the South Pole. - We took turns when we were carefully installing sensors on the telescope. Otherwise our hands quickly froze and became useless, says Chad who spent two months there in the summer.

Chad Finley, associate professor Fysikum. Foto: Gunilla Häggström
Chad Finley, associate professor Fysikum. Foto: Gunilla Häggström

Chad Finley grew up all over the US: Texas, Tennessee, Connecticut, and finally New York City.


When did you get interested in physics?

“I remember specifically when I was 8 years old, and I found a book in my school library about atoms.  It was a short, very simple book with cartoon diagrams. But the idea of atoms being the building blocks of everything amazed me. Before that, I was interested in animals, biology, and dinosaurs, and then suddenly I was fascinated by physics and soon after astronomy.”

He graduated in Physics with a PhD at Columbia University in New York in 2006 and became interested in astroparticle physics, the intersection of particle physics and astrophysics. He was a Postdoc from 2006 to 2009 at the University of Wisconsin, Madison, which is the headquarters for the IceCube Neutrino Observatory. IceCube is a neutrino telescope built into the glacial ice at the South Pole.  It consists of 86 holes drilled 2.5 km deep into the ice and filled with sensors, creating a 3D array of more than 5000 sensors distributed throughout a cubic kilometer of ice.  The sensors detect light when a high-energy neutrino from space interacts with an atom in the ice.

Inside an IceCube string Credit
Inside an IceCube string Credit: IceCube/NSF The deployment of each of the 86 IceCube strings lasted about 11 hours. In each one, 60 sensors (called DOMs) had to be quickly installed before the ice completely froze around them.

The importance of the Oskar Klein Centre

Chad Finley joined the OKC in 2009 as an OKC Fellow, where he continued as point-source analysis coordinator for IceCube.
“At the OKC one is continually exposed to new ideas as they emerge in neighbouring fields, creating a superb environment for cross-disciplinary research.”
Chad uses neutrinos to identify the astronomical sources where cosmic rays are born and to understand the physical processes that create them. He is now Associate Professor in the Physics Department at Stockholm University and Deputy Director of the OKC.

Grants from the Swedish Research Council

Chad received a VR special researcher grant in 2010 and got a permanent position in the Department of Physics from 2011. Since then he has worked both with research and teaching. He has received a new grant in 2022 for the project: Astrophysical neutrinos with IceCube: deep learning in deep ice.

Research below zero

Chad stayed in Antarctica for two months. That was when it was summer there with bright light all day and temperatures usually between -20 and -40 degrees. In the winter it's dark all the time and goes down to -70 degrees.

Chad Finley bedriver forskning vid Sydpolen i IceCube-projeket
Chad Finley bedriver forskning vid Sydpolen i IceCube-projeket


“To get to the South Pole we flew first from New Zealand to the Antarctic coast, and then continued from there by turboprop military plane equipped with skis. The ice sheet is about 3 kilometres thick and the South Pole station hosts up to 200 people in the summer who conduct research in many fields. IceCube researchers go during the summer to upgrade the telescope equipment and test new projects.  It is a short season and since the sun is up all day, there is always some work going on around the clock.  Mealtimes occur every six hours (and the cooks are very good!). Then most people leave by February as winter approaches. 

Only a few will remain through the long Antarctic night to keep the telescope operating. Martin Wolf, a former PhD at Fysikum, stayed there during the pandemic, both at summer and winter, when many countries were closed and had quarantine periods."

At home Chad analyses the data from IceCube, which is sent over satellite. The IceCube Collaboration has found the first evidence of high-energy neutrino emission from a nearby galaxy. The galaxy, NGC 1068 (also known as Messier 77) is an active galaxy roughly 47 million light years away in the constellation Cetus and one of the most familiar and well-studied active galaxies. “It is very exciting to be able to see neutrinos from such a galaxy so close (astronomically speaking).” The results are published in Science.

What is your advice to physics students?

“If you are interested in research, I would encourage you above all to get experience doing research. Some of this will come as part of thesis work, but it can also be an internship project with a research group.  There are many ways of doing research and it is good to get a variety of experiences, to get an idea which ones feel like a good fit for your strengths and interests.  Physics research is really different from a physics class. Much of the time there are not clear-cut answers, but this is exactly what makes it exciting!”

Are you also interested in physics?

At the Department of Physics at Stockholm University, we offer high-quality education with a strong connection to frontier research. We promise exciting studies in tight student groups and with active researchers as your teachers.

More information

Courses and Programmes (studying physics at the Department of Physics at the Stockholm University)

IceCube neutrinos provide new view of a nearby galaxy

Evidence for neutrino emission from the nearby active galaxy NGC 1068, Article in Science, The IceCube Collaboration: R. Abbasi et al. DOI:10.1126/science.abg3395