The NESTOR Project (Neutrino Extended Submarine Telescope with Oceanographic Research Project) is an international scientific collaboration whose target is the deployment of a neutrino telescope on the sea floor off Pylos, Greece.

Neutrino

Neutrinos A neutrino ( ; denoted by the Greek letter ) is an elementary particle that interacts via the weak interaction and gravity. The neutrino is so named because it is electrically neutral and because its rest mass is so small ('' -ino'') that it ...

are elementary particles first detected in the 1950s, long after their theoretical prediction by theorist

Wolfgang Pauli Wolfgang Ernst Pauli ( ; ; 25 April 1900 – 15 December 1958) was an Austrian theoretical physicist and a pioneer of quantum mechanics. In 1945, after having been nominated by Albert Einstein, Pauli received the Nobel Prize in Physics "for the ...

. Neutrinos (or anti-neutrinos) are created during certain

nuclear reactions In nuclear physics and nuclear chemistry, a nuclear reaction is a process in which two nuclei, or a nucleus and an external subatomic particle, collide to produce one or more new nuclides. Thus, a nuclear reaction must cause a transformation o ...

, where

proton A proton is a stable subatomic particle, symbol , Hydron (chemistry), H+, or 1H+ with a positive electric charge of +1 ''e'' (elementary charge). Its mass is slightly less than the mass of a neutron and approximately times the mass of an e ...

s are transformed into

neutron The neutron is a subatomic particle, symbol or , that has no electric charge, and a mass slightly greater than that of a proton. The Discovery of the neutron, neutron was discovered by James Chadwick in 1932, leading to the discovery of nucle ...

s and vice versa. Neutrinos do not interact with matter via either the

electromagnetic In physics, electromagnetism is an interaction that occurs between particles with electric charge via electromagnetic fields. The electromagnetic force is one of the four fundamental forces of nature. It is the dominant force in the interacti ...

, the strong nuclear, or gravitational forces, since they are electrically neutral leptons and their

rest mass The invariant mass, rest mass, intrinsic mass, proper mass, or in the case of bound systems simply mass, is the portion of the total mass of an object or system of objects that is independent of the overall motion of the system. More precisely, ...

is very small. They interact with the

nucleon In physics and chemistry, a nucleon is either a proton or a neutron, considered in its role as a component of an atomic nucleus. The number of nucleons in a nucleus defines the atom's mass number. Until the 1960s, nucleons were thought to be ele ...

s (neutrons and protons) only via weak nuclear interactions. Since they do not interact with matter via the electromagnetic or gravitational forces, it is extremely difficult to detect them. Since their mass is very small (less than 14 eV) they travel with speeds that are very close to the speed of light in

vacuum A vacuum (: vacuums or vacua) is space devoid of matter. The word is derived from the Latin adjective (neuter ) meaning "vacant" or "void". An approximation to such vacuum is a region with a gaseous pressure much less than atmospheric pressur ...

NESTOR Telescope

Because neutrinos are very weakly interacting, neutrino detectors must be very large to detect a significant number of neutrinos. After completion, NESTOR will consist of a large number of glass balls (the "eyes") containing

photomultiplier A photomultiplier is a device that converts incident photons into an electrical signal. Kinds of photomultiplier include: * Photomultiplier tube, a vacuum tube converting incident photons into an electric signal. Photomultiplier tubes (PMTs for sh ...

tubes. The "eyes" are connected with star-shaped

titanium Titanium is a chemical element; it has symbol Ti and atomic number 22. Found in nature only as an oxide, it can be reduced to produce a lustrous transition metal with a silver color, low density, and high strength, resistant to corrosion in ...

frames. Many frames compose a NESTOR tower. The whole construction is placed at the bottom of the sea to reduce noise from

cosmic radiation Cosmic rays or astroparticles are high-energy particles or clusters of particles (primarily represented by protons or atomic nuclei) that move through space at nearly the speed of light. They originate from the Sun, from outside of the Sol ...

(depth 4000m). The detectors are connected with the terminal station through a 31-km-long deep-sea,

optic fiber An optical fiber, or optical fibre, is a flexible glass or plastic fiber that can transmit light from one end to the other. Such fibers find wide usage in fiber-optic communications, where they permit transmission over longer distances and at ...

cable for data collection.

Pylos Pylos (, ; ), historically also known as Navarino, is a town and a former Communities and Municipalities of Greece, municipality in Messenia, Peloponnese (region), Peloponnese, Greece. Since the 2011 local government reform, it has been part of ...

was selected for the installation of the telescope for several reasons. It combines deep water with close proximity to the shore, a convenient combination for the installation of the NESTOR towers and the communication and power supply cables. It is also located in an anti-diametric point with respect to the DUMAND neutrino telescope in the

Pacific The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is bounded by the cont ...

ocean and therefore, it is possible to compare observations and study correlations between the observed neutrino. Original surveys of the seafloor were conducted in 1989, 1991, 1992 and scientific conferences of the NESTOR Collaboration were held in the 1990s. In March 2003, the NESTOR prototype was lowered to the depth of 3800 meters some 30 kilometers off the coast of

Greece Greece, officially the Hellenic Republic, is a country in Southeast Europe. Located on the southern tip of the Balkan peninsula, it shares land borders with Albania to the northwest, North Macedonia and Bulgaria to the north, and Turkey to th ...

. The prototype's results were published in 2005. The spokesperson for the project is Leonidas Resvanis from

University of Athens The National and Kapodistrian University of Athens (NKUA; , ''Ethnikó kai Kapodistriakó Panepistímio Athinón''), usually referred to simply as the University of Athens (UoA), is a public university in Athens, Greece, with various campuses alo ...

. In 2014 the project was still applying funding to build the actual telescope. The NESTOR collaboration is now (2018) part of the

KM3NeT The Cubic Kilometre Neutrino Telescope, or KM3NeT, is a European research infrastructure located at the bottom of the Mediterranean Sea. It hosts water Cherenkov radiation, Cherenkov neutrino astronomy, neutrino telescopes designed to detect and st ...

-collaboration. As such, they are not developing the NESTOR telescope anymore as its own instance, but Km3Net has a planned telescope site off the coast of Pylos (which can thus be seen as a continuation of the NESTOR project to build an underwater telescope off the coast of Pylos).

References

External links

Official Webpage

* ttps://inspirehep.net/experiments/1110447 NESTORexperiment record on

INSPIRE-HEP INSPIRE-HEP is an open access digital library for the field of high energy physics (HEP). It is the successor of the Stanford Physics Information Retrieval System (SPIRES) database, the main literature database for high energy physics since the 1 ...

{{coord missing, Greece Neutrino observatories Neutrino astronomy Particle experiments Astronomical observatories in Greece

Neutrino

NESTOR Telescope

See also

References

Further reading

External links