South Pole Science: Ice Cube

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.

A DOM named Wormwood.

A DOM named Wormwood.

Another look at Wormwood.

Another look at Wormwood.

 

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.

 

http://newscenter.lbl.gov

A diagram from the Lawrence Berkeley National Lab’s website.

Outside the ICL. Each can on the side of the building brings in DOM cables and sends power to the DOMs.

Outside the ICL. Each can on the side of the building brings in DOM cables and sends power to the DOMs.

The cables then run inside the building, where the cables for each DOM split up and are distributed to specialized computers for processing the incoming data.

The cables then run inside the building, where the cables for each DOM split up and are distributed to specialized computers for processing the incoming data.

The data and status of the DOM is analyzed by these machines which relays the information to a central program. (Sorry guys if I've butchered this description too much!)

The data and status of the DOM is analyzed by these machines which relays the information to a central program. (Sorry guys if I’ve butchered this description too much!)

Cables run to the computers.

Cables and computers.

 

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.

 

A simulation of the neutrino detection, based on the reception of muons/blue light. Each teeny tiny white dot is one of the DOMs beneath the ice, and the colors represent the timing of blue light detection that is used to calculate the trajectory of the neutrino.

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!

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3 thoughts on “South Pole Science: Ice Cube

  1. Maddy – you are so smart! and cool! I am a friend of your grandma (Dianne) and she is so proud of you! She shared your blog with her NPBC members because one of our reads is about Sir Ernest Shackleton. If you ever want to speak to a class of high school math students let me know. I think they would be fascinated to learn about your endeavors.

    Take care!
    Dolly

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