KM3NeT

Telescopes are not usually dual-purpose instruments – except for the KM3NeT underwater detector.

Occupying a cubic kilometer (hence the acronym) of the Mediterranean, this device will focus on watching cosmic and underwater events, and it will be the world’s largest deep-sea detector when it is finished, with applications for astrophysics and planetary science. Three kilometers below the surface of the sea, KM3NeT will search for subatomic neutrino particles from space. Giorgio Riccobene, a KM3NeT astroparticle physicist said: “It will be the second largest human structure after the Great Wall of China.”

Using an array of thousands of photon-sensors, KM3NeT will identify any Cherenkov radiation, or ‘blue light,’  created when neutrinos interact with matter, with each other or with different particles underwater. (Neutrinos are the result of cosmic rays colliding with interstellar matter in space, pulsars, gamma-ray bursts and even nuclear reactions within our sun.) Finding them can be a challenge: neutrinos are similar to electrons, only they do not carry any electrical charge, are affected by the weak nuclear force and gravity, easily pass through normal matter. Thus, they cannot be seen and are hard to detect – which is one reason why researchers have to spread a wide net.
 
A secondary goal of the detector is to uncover the existence of mysterious dark matter. One theory is that dark matter is made up of Weakly Interacting Massive Particles (WIMPs). Neutrinos may be produced through WIMP collisions within regions of space that have higher quantities of dark matter. This includes places like our sun. Scientists might indirectly detect WIMPs from these reactions by looking for anomalous readings in solar neutrinos rate of flow as they are expelled.

To efficiently coordinate data storage and processing with institutions around the world, the  project’s designers are considering doing their computing with grid. A ‘decentralized’ computing resource will enable them avoid the accidental loss of data by simultaneously copying primary research information to other remote facilities, at the instant data is collected.
 

Healthy Competition

Construction of KM3NeT – an ESFRI project, involving 40 institutes and university groups from ten countries -- is planned to begin in 2013, with data collection anticipated for 2014.

At the same time, the IceCube neutrino detector is being built at the South Pole. But where KM3NeT use one cubic kilometer of seawater, IceCube will use a cubic kilometer of glacial ice.

Even though IceCube is almost finished and already collecting data, KM3NeT will be up to five times larger, with better detection sensitivity, its supporters say. This is due to water having a better angular resolution than ice for detecting neutrinos: ice disperses light photons more erratically, consequently particle track reconstruction is difficult.  Also, KM3NeT will have a better view of our galaxy’s center, (a likely candidate for neutrinos) because it is located on a side of the Earth that faces the Milky Way for longer periods.
 
Although the projects are competitors in one sense, they are also collaborators, with IceCube scientists lending their own software platform to KM3NeT and meeting regularly to coordinate the construction of the detector. “Building a kilometer-scale detector in a natural environment is devilishly challenging,” said Francis Halzen of IceCube. He stated that they do not want to make things worse by interfering with each other in this highly competitive field.

In addition to serving the fields of astrophysics, the telescope will serve as an underwater laboratory for fields as diverse as climatology, geosciences, marine biology and oceanography.

Riccobene likes to look at the big picture when describing the project, saying: “We are exploring the sea’s abysses, and searching for ‘poltergeist’ particles produced inside powerful astrophysical sources at the very edge of the universe.”

- Adrian Giordani, iSGTW