ANTARES is the name of a
neutrino detector
A neutrino detector is a physics apparatus which is designed to study neutrinos. Because neutrinos only weakly interact with other particles of matter, neutrino detectors must be very large to detect a significant number of neutrinos. Neutrino d ...
residing 2.5 km under the
Mediterranean Sea
The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the ...
off the coast of
Toulon
Toulon (, , ; oc, label= Provençal, Tolon , , ) is a city on the French Riviera and a large port on the Mediterranean coast, with a major naval base. Located in the Provence-Alpes-Côte d'Azur region, and the Provence province, Toulon is th ...
,
France
France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of overseas regions and territories in the Americas and the Atlantic, Pacific and Indian Oceans. Its metropolitan area ...
. It is designed to be used as a directional neutrino telescope to locate and observe
neutrino
A neutrino ( ; denoted by the Greek letter ) is a fermion (an elementary particle with spin of ) that interacts only via the weak interaction and gravity. The neutrino is so named because it is electrically neutral and because its rest mass ...
flux from cosmic origins in the direction of the
Southern Hemisphere of the
Earth
Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surfa ...
, a complement to the South Pole neutrino detector
IceCube
The IceCube Neutrino Observatory (or simply IceCube) is a neutrino observatory constructed at the Amundsen–Scott South Pole Station in Antarctica. The project is a recognized CERN experiment (RE10).
Its thousands of sensors are located under ...
that detects neutrinos from both hemispheres. The name comes from Astronomy with a Neutrino Telescope and Abyss environmental RESearch project; the
acronym
An acronym is a word or name formed from the initial components of a longer name or phrase. Acronyms are usually formed from the initial letters of words, as in ''NATO'' (''North Atlantic Treaty Organization''), but sometimes use syllables, as ...
is also the name of the prominent star
Antares
Antares is the brightest star in the constellation of Scorpius. It has the Bayer designation α Scorpii, which is Latinised to Alpha Scorpii. Often referred to as "the heart of the scorpion", Antares is flanked by σ Scorpii and τ ...
. The experiment is a recognized
CERN experiment (RE6). Other neutrino telescopes designed for use in the nearby area include the
Greek
Greek may refer to:
Greece
Anything of, from, or related to Greece, a country in Southern Europe:
*Greeks, an ethnic group.
*Greek language, a branch of the Indo-European language family.
**Proto-Greek language, the assumed last common ancestor ...
NESTOR telescope and the
Italian
Italian(s) may refer to:
* Anything of, from, or related to the people of Italy over the centuries
** Italians, an ethnic group or simply a citizen of the Italian Republic or Italian Kingdom
** Italian language, a Romance language
*** Regional Ita ...
NEMO telescope, which are both in early design stages. The data taking of ANTARES was finished in February 2022, after 16 years of continuous operation.
Design
The array contains a set of twelve separate vertical strings of
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. Each one has 75 optical modules and is about 350 meters long. They are anchored at the bottom of the sea at a depth of about 2.5 km, roughly 70 meters apart from each other. When neutrinos enter the southern hemisphere of the earth, they usually continue traveling directly through it. On rare occasions, a few
muon neutrinos interact with the water in the Mediterranean Sea. When this happens, they produce a
high energy muon. ANTARES works by its photomultiplier tubes detecting the
Cherenkov radiation emitted as the muon passes through the water. The detection techniques used discriminate between the signature of "upward-going muons", a muon neutrino that has had interactions with matter below the detector (the
Earth
Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surfa ...
), and much higher flux of "downward atmospheric muons".
In contrast to the
South Pole
The South Pole, also known as the Geographic South Pole, Terrestrial South Pole or 90th Parallel South, is one of the two points where Earth's axis of rotation intersects its surface. It is the southernmost point on Earth and lies antipod ...
neutrino telescopes
AMANDA and
IceCube
The IceCube Neutrino Observatory (or simply IceCube) is a neutrino observatory constructed at the Amundsen–Scott South Pole Station in Antarctica. The project is a recognized CERN experiment (RE10).
Its thousands of sensors are located under ...
, ANTARES uses water instead of ice as its Cherenkov medium. As light in water is less scattered than in ice this results in a better
resolving power. On the other hand, water contains more sources of background light than ice (
radioactive
Radioactive decay (also known as nuclear decay, radioactivity, radioactive disintegration, or nuclear disintegration) is the process by which an unstable atomic nucleus loses energy by radiation. A material containing unstable nuclei is consi ...
isotopes
potassium
Potassium is the chemical element with the symbol K (from Neo-Latin ''kalium'') and atomic number19. Potassium is a silvery-white metal that is soft enough to be cut with a knife with little force. Potassium metal reacts rapidly with atmosph ...
-40 in the sea salt and
bioluminescent organisms), leading to a higher energy thresholds for ANTARES with respect to IceCube and making more sophisticated background-suppression methods necessary.
Construction history
The construction of ANTARES was completed on May 30, 2008, two years after the first string was deployed.
Initial testing began in 2000. Equipment indirectly related to the detector such as a
seismometer
A seismometer is an instrument that responds to ground noises and shaking such as caused by earthquakes, volcanic eruptions, and explosions. They are usually combined with a timing device and a recording device to form a seismograph. The outpu ...
were deployed in 2005. The first string of photomultiplier tubes was moved into place in February 2006. In September 2006 the second line was successfully connected. Lines 3, 4 and 5 were deployed at the end of 2006 and connected in January 2007. This was an important step that made Antares the biggest neutrino telescope in the Northern hemisphere (surpassing the
Baikal neutrino telescope
The Baikal Deep Underwater Neutrino Telescope (BDUNT) (russian: Байкальский подводный нейтринный телескоп) is a neutrino detector conducting research below the surface of Lake Baikal (Russia) since 2003. The ...
). Lines 6, 7, 8, 9, and 10 were deployed between March and early November 2007 and connected in December 2007 and January 2008. From May 2008 the detector has been running in its complete 12-line configuration.
Deployment and connection of the detector are performed in cooperation with the French
oceanographic
Oceanography (), also known as oceanology and ocean science, is the scientific study of the oceans. It is an Earth science, which covers a wide range of topics, including ecosystem dynamics; ocean currents, waves, and geophysical fluid dynamic ...
institute,
IFREMER
IFREMER (Institut Français de Recherche pour l'Exploitation de la Mer; ) is an oceanographic institution in Brest, France.
Scope of works
Ifremer focuses its research activities in the following areas:
* Monitoring, use and enhancement of coa ...
, currently using the
ROV Victor, and for some past operations the
submarine Nautile
''Nautile'' is a crewed submersible owned by Ifremer, the French Research Institute for Exploitation of the Sea. Commissioned in 1984, the submersible can be operated at depths of up to .
''Nautile'' is capable of housing three people. It has a ...
.
Experimental goals
The ANTARES project complements the
IceCube Neutrino Observatory
The IceCube Neutrino Observatory (or simply IceCube) is a neutrino observatory constructed at the Amundsen–Scott South Pole Station in Antarctica. The project is a recognized CERN experiment (RE10).
Its thousands of sensors are located under ...
in
Antarctica
Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean, it contains the geographic South Pole. Antarctica is the fifth-largest cont ...
. The detection principles of the two projects are very similar, although ANTARES only points toward the Southern Hemisphere. Thanks to its location in the Mediterranean Sea, ANTARES is more sensitive to neutrinos with energies below 100 TeV in the southern sky, a region that includes many galactic sources. ANTARES will detect neutrinos from high energy origin, particularly in the range from 10
10 to 10
14 electronvolt
In physics, an electronvolt (symbol eV, also written electron-volt and electron volt) is the measure of an amount of kinetic energy gained by a single electron accelerating from rest through an electric potential difference of one volt in vacuum ...
s (10
GeV GEV may refer to:
* ''G.E.V.'' (board game), a tabletop game by Steve Jackson Games
* Ashe County Airport, in North Carolina, United States
* Gällivare Lapland Airport, in Sweden
* Generalized extreme value distribution
* Gev Sella, Israeli-Sou ...
- 100
TeV). Over many years of operation, it may be able to produce a map of the neutrino
flux from cosmic origins in the Southern Hemisphere. Of particular interest would be the detection of astrophysical point sources of neutrinos, possibly in correlation with observations in other bands (such as gamma rays sources observed by the
HESS Hess or Heß may refer to:
* Hess (surname), also ''Heß'' in German, people with the surname Hess
* Hess, Oklahoma, a community in the United States
* Hess Educational Organization, the largest private provider of English instruction in the Rep ...
telescope in
Namibia
Namibia (, ), officially the Republic of Namibia, is a country in Southern Africa. Its western border is the Atlantic Ocean. It shares land borders with Zambia and Angola to the north, Botswana to the east and South Africa to the south and ea ...
, which has a common field of view with ANTARES).
Apart from this astro-particle physics aspect, the ANTARES telescope may also tackle some fundamental problems in particle physics, such as the search for
dark matter
Dark matter is a hypothetical form of matter thought to account for approximately 85% of the matter in the universe. Dark matter is called "dark" because it does not appear to interact with the electromagnetic field, which means it does not a ...
in the form of
neutralino
In supersymmetry, the neutralino is a hypothetical particle. In the Minimal Supersymmetric Standard Model (MSSM), a popular model of realization of supersymmetry at a low energy, there are four neutralinos that are fermions and are electrically ...
annihilation
In particle physics, annihilation is the process that occurs when a subatomic particle collides with its respective antiparticle to produce other particles, such as an electron colliding with a positron to produce two photons. The total energy ...
in the
Sun
The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...
(normal
solar neutrinos being outside the energy range of ANTARES) or the
Galactic Center
The Galactic Center or Galactic Centre is the rotational center, the barycenter, of the Milky Way galaxy. Its central massive object is a supermassive black hole of about 4 million solar masses, which is called Sagittarius A*, a compact ra ...
. Due to the very different methods employed, its expected sensitivity is complementary to the direct dark matter searches performed by various experiments such as
DAMA,
CDMS and at the
LHC. Detection of neutralino signals would also confirm
supersymmetry, but is not generally considered very likely at the ANTARES sensitivity level. Other possible "exotic" phenomena that could conceivably be measured by ANTARES include
nuclearites or
magnetic monopoles
In particle physics, a magnetic monopole is a hypothetical elementary particle that is an isolated magnet with only one magnetic pole (a north pole without a south pole or vice versa). A magnetic monopole would have a net north or south "magneti ...
.
Results
The first neutrino detections were reported in Feb 2007.
Using 6 years of data, a search of the galactic center for point sources of neutrinos found none. Atmospheric neutrino oscillations were also measured.
[
]
Additional instrumentation
In addition to the main optical detector for cosmic neutrinos, the ANTARES experiment also houses a number of instruments for the study of the
deep sea
The deep sea is broadly defined as the ocean depth where light begins to fade, at an approximate depth of 200 metres (656 feet) or the point of transition from continental shelves to continental slopes. Conditions within the deep sea are a combin ...
environment, such as
salinity and
oxygen
Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as ...
probes,
sea current profilers and instrumentation for the measurement of light transmission and sound velocity. Also, a camera system has been installed for automatic tracking of
bioluminescent organisms. Results from these instruments, while also important for the calibration of the detector, will be shared with ocean science institutes involved in the ANTARES collaboration. While the ANTARES detector contains an acoustic positioning system for the alignment of the free-floating detector lines, it also houses a separate dedicated acoustic detection system
AMADEUS
Amadeus may refer to:
*Wolfgang Amadeus Mozart (1756–1791), prolific and influential composer of classical music
*Amadeus (name), a given name and people with the name
* ''Amadeus'' (play), 1979 stage play by Peter Shaffer
* ''Amadeus'' (film), ...
, which will comprise 6 converted ANTARES storeys with hydrophones to evaluate the possibility for acoustic detection of neutrinos in the deep sea. The first 3 of these acoustic storeys have been included in the ''instrumentation line'', the other 3 on the 12th line.
References
External links
ANTARES homeIFREMER homepageKM3NeT neutrino telescope*Record
r ANTARESon
INSPIRE-HEP
{{Neutrino detectors
Mediterranean Sea
Neutrino observatories
Particle experiments
CERN experiments