Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Detector at the South Pole explores the mysterious neutrinos


Neutrinos are a type of particle that pass through just about everything in their path from even the most distant regions of the universe. The Earth is constantly bombarded by billions of neutrinos, which zip right through the entire globe, houses, animals, people - everything.

Only very rarely do they react with matter, but the giant IceCube experiment at the South Pole can detect when there is a collision between neutrinos and atoms in the ice using a network of detectors. New research results from the Niels Bohr Institute among others have measured the neutrinos at the South Pole and have calculated some of the physical properties of the otherwise exotic and poorly understood particles. The results are published in the scientific journal Physical Review D.

Jason Koskinen is shown at the South Pole. In the background is the IceCube Lab. All data from the instruments deep down in the ice comes up through the two "towers" and into the computer center, where the first analyses are done.

Credit: T. Waldemaier

Neutrinos are among nature's most abundant particles. Their number far exceeds the number of atoms in the entire universe - yet we know little about them. Neutrinos are a type of particle created in the Big Bang and are also produced in the Sun's interior and in violent events like supernovae, which are exploding stars. Neutrinos are also called 'ghost particles' because they basically do not interact with matter, but pass undisturbed through everything in their path.

Instruments at the South Pole

Researchers from 44 institutions in 12 countries are part of an international project, IceCube at the South Pole to study the mysterious particles with the strange properties.

IceCube is an enormous particle detector located deep in the ice at the South Pole. The instruments in the detector are comprised of 86 cables each with 60 digital Optical Modules (extremely sensitive light sensors). Each cable is lowered down into a hole, which is melted through the 2½ km ice sheer using a hot water drill. The detector is located deep below the surface - it starts 1½ km below the ice and ends at the bottom at a depth of 2½ km.

The detector's enormous size of a cubic kilometer is necessary because neutrinos interact extremely weakly with matter, so it is only rarely that they collide with the atoms in the ice. When they finally collide, charged particles are created, which emit radiation that can be detected by the extremely sensitive Digital Optical Modules.

"In the Ice Cube project we have registered about 35 neutrinos, which are very likely to have come distant regions in space. They have a very high energy and because they have not interacted during their long journey, they can carry information from the most distant parts of the universe. In addition to the rare cosmic neutrinos, we are also studying the neutrinos created in the Earth's atmosphere in order to unravel the physical properties of neutrinos," says Jason Koskinen, Assistant Professor and head of the IceCube Group at the Niels Bohr Institute, University of Copenhagen.

From the North Pole to the South Pole

When particles (protons) with high energy - from violent events in the cosmos like supernovae and quasars hit the Earth's atmosphere, a burst of neutrinos is formed, which passes through the Earth. The neutrinos formed over the North Pole pass straight through the Earth and very small proportion of them hit the ice at the South Pole, where the IceCube detector registers the collisions.

Neutrinos are very light particles and for many years it was believed that they were completely massless. It is now believed that there are three types of neutrinos (electron, muon and tau neutrinos), each with their specific mass, which is incredibly small - less than a millionth of the mass of an electron.

"The neutrinos created in the atmosphere over the North Pole are mostly muon neutrinos. On their way through the Earth's 13,000 km, the muon neutrinos undergo quantum fluctuations that can change them into another type of neutrino, tau neutrinos, before they are finally detected by IceCube on the other side of the globe. We can now study these effects in much greater detail than before and in this way we can gain new insights into their physical characteristics," explains Jason Koskinen.

Atmospheric neutrinos

The research group has now studied atmospheric neutrinos in the IceCube detector at the South Pole for three years and have analysed 5,200 interactions between atmospheric neutrinos and atoms in the ice.

"We have confirmed that neutrinos undergo fluctuations - even at high energy levels and we have calculated how much they exhibit these oscillations. In this study, we have only measured muon neutrinos and in comparison to how many muon neutrinos form in in the atmosphere and pass through the Earth, we only see a fraction at the South Pole. The explanation is that the muon neutrinos undergo quantum fluctuations that change them into tau neutrinos and we do not see those. If they had not changed, we would see them all. Our calculations show that 20 percent have undergone quantum fluctuations and changed from muon neutrinos to another type of neutrino as they pass through the Earth," explains Jason Koskinen.

Messengers from the universe

And then what, you might ask? "Because we basically want to learn more about these strange particles that are everywhere in the universe and whose properties we still do not fully understand. Because neutrinos come from the cosmos, we could use them for astronomical observations and gain new insights into the structure of the universe," says Jason Koskinen.




Jason Koskinen, Assistant Professor and head of the IceCube Group at the Niels Bohr Institute, University of Copenhagen, +45 2128-9061,

Morten Medici, PhD student, IceCube Group at the Niels Bohr Institute, University of Copenhagen, +45 3532-5454, +45 6151-6464,

Gertie Skaarup | EurekAlert!

More articles from Physics and Astronomy:

nachricht First results of NSTX-U research operations
26.10.2016 | DOE/Princeton Plasma Physics Laboratory

nachricht Scientists discover particles similar to Majorana fermions
25.10.2016 | Chinese Academy of Sciences Headquarters

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Etching Microstructures with Lasers

Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.

This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...

Im Focus: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

3-D-printed structures shrink when heated

26.10.2016 | Materials Sciences

Indian roadside refuse fires produce toxic rainbow

26.10.2016 | Health and Medicine

First results of NSTX-U research operations

26.10.2016 | Physics and Astronomy

More VideoLinks >>>