How About...IceCube and Neutrinos?

Antarctica's IceCube Neutrino Observatory ready to go at full capacity.

Would you like to have a cool glass of water with two maybe three IceCubes and a trillion of Neutrinos?

Well, independently of what was your answer, just while you were thinking about it, a couple trillions of Neutrinos just collided with you. Did you even notice that? of course not,  Neutrinos are the only known particles that can go through matter without disturbing it!

That is why just while I am writing these, and you reading it,  thousands of Neutrinos just passed through our body. But don't worry, they are not harmful (or at least not yet, jk!) they carry no electrical charge and are considered a massless particle which carry off energy in radioactive ß-disintegration.

Wolfgang Pauli

A neutrino is a very special particle, it was not until 1930 when Wolfgang Pauli first proposed the existence of  it. This Nobel Prize winner, born in Vienna 1900 April 25th, was studying the conservation of energy, conservation of momentum and  angular momentum during the atomic nucleus decay.

Wolfgang Pauli named this particle Neutron,  two years later James Chadwick had found a much more massive particle and named it also Neutron. Then Enrico Fermi came up with his radioactive ß-decay method, and renamed Pauli's Neutron: Neutrino to avoid any other confusion. 

By the way, Neutrino in Italian means: The little neutral one.

There are three types of Neutrinos (or at least the ones known until now...) Electron-Neutrino,  Muon-Neutrino and  Tau-Neutrino. This time I'm going to concentrate on Muon-Neutrino type.

Going back the the IceCube, this is the name of the world's largest Neutrino Observer. It is located at the Earth's South Pole (Antarctica), full name : IceCube Neutrino Detector.

The IceCube Neutrino Observatory covers an area of one kilometre, the special size needed since 1950 when Scientists began wondering how to detect Neutrinos.

The description of Neutrinos and reason why they need such big area, made by the IceCube Neutrino Detector is:

"Unlike other particles, neutrinos are antisocial, difficult to trap in a detector. It is the feeble interaction of neutrinos with matter that makes them uniquely valuable as astronomical messengers. Unlike photons or charged particles, neutrinos can emerge from deep inside their sources and travel across the universe without interference. They are not deflected by interstellar magnetic fields and are not absorbed by intervening matter. However, this same trait makes cosmic neutrinos extremely difficult to detect; immense instruments are required to find them in sufficient numbers to trace their origin." (IceCube Neutrino Detector) 

So how do scientists at IND, are able to detect Neutrinos? Why is the observatory located at the South Pole?

Neutrino Observatory at Antarctica

 Well just as Space Shuttles are launched at Cape Canaveral (because of the geographical location), scientists at IND also took advantage of our own nature. Yes, scientists use Ice at South Pole, to  detect Neutrinos in an easier way.

The phenomenon they take advantage of is as follows:

Do you remember about the glass of water and neutrinos? well, since there are trillions of neutrinos passing through Earth every second, scientists found out that whenever there is a Neutrino colliding (well it can't be precisely called like that..since a collision causes a change, either velocity, momentum etc. and neutrinos don't, how should it be called?)   with an Ice particle, Muons are produced. 

Holes and Sensors arrangement

So? Well, when Muons are produced at the highly ultra-transparent Ice, the 5,160 sensors installed at the 86 drilled holes detect this particle. But what now? Why are scientists detecting Muons?

Blue path left by Muons

Very simple, when Neutrinos pass through ice particles, muons are produced and they leave a blue light, which is detected by the sensors. 

In this way, scientists are able to track Muons and at the same time Neutrinos, because they actually follow the same path that Neutrinos had. Then they can simply track back the Neutrinos path, and since Neutrinos are astronomical messengers, they can also track our cosmic history.

Very simple isn't it?  Well actually...not  , since for every Muon detected from a Cosmic Neutrino IceCube detects a million more muons produced by cosmic rays in the atmosphere above the detector. 

In order to filter this tremendous load of data, IceCube Observer takes advantage of Neutrinos' property to pass through matter with no change.  They use Earth as a gigantic filter, in order to isolate only Cosmic Neutrinos, and then they only take a look through the Earth, towards the North skies, to select the Neutrinos.

How about...knowing about what happened 13.9 billions of years ago..thanks to a massless particle that has been trying to tell us a whole life of stories.

Thanks!

I.