The Ice Cube project is on the hunt for neutrinos! To be honest, I didn’t even understand what a neutrino was until this past weekend. It sounds like some nourishing snack produced by Nabisco. Thankfully, Mike DuVernois from the University of Wisconsin—Madison gave us a science lecture on these tiny little guys and the gigantic detector setup they have here at the South Pole.
A neutrino is a subatomic particle—like a proton, neutron or electron—that we cannot see. They are formed from the splitting of atoms, like in nuclear reactions where a larger element loses electrons and protons and gives off energy. So neutrinos are formed in many different ways, even within the human body! But Ice Cube is specifically looking for high-energy neutrinos that were formed by the Big Bang.
Why study neutrinos? As their name may hint: neutrinos have a neutral charge and are very tiny, making it difficult for them to react with other objects or be absorbed. This makes the little particles a great point back to their origin, so that these scientists can study their sources, detect supernovas, study cosmic rays, etc.
How are neutrinos detected? How can we possibly detect something that cannot be seen? Well, when the neutrino interacts with something it produces a muon—another particle—and blue light (Cherenkov radiation). Devices called Digital Optical Modules (DOMs) that track the trail of light produced in this reaction.
Really cool side fact: each DOM has a name. Yep, all five thousand plus. Most are named after tropical diseases.
Within approximately one cubic kilometer of ice, over five thousand DOMs are strung together and embedded in the ice between about 1500 and 2500 meters depth, with cables running back up to the surface to relay information and provide power.
These cables then connect to custom-made computers that analyze the data and formulate a simulation of each neutrino event. Many different types of events are observed, but the pattern of colors/dots that light up on this simulation allow the Ice Cube scientists to differentiate between high and low-energy neutrino events.
Another cool fact: The first thirty-something neutrino events discovered here were named after Sesame Street characters, with Bert and Ernie being the first two.
This is about as much as I know and understand about this project. Anyone reading this, please correct me if I’m wrong! Future plans for Ice Cube include a potential expansion to a 10km^3 area… there’s much more data to be collected, so this is a project worth keeping an eye on!
Stay tuned for more South Pole Science posts!