- Email: [email protected]
The ANTARES deep-sea neutrino telescope: Operation and calibration
Nuclear Instruments and Methods in Physics Research A 639 (2011) 26–29
Contents lists available at ScienceDirect
Nuclear Instruments and Methods in Physics Research A journal homepage: www.elsevier.com/locate/nima
The ANTARES deep-sea neutrino telescope: Operation and calibration Heide Costantini Istituto Nazionale di Fisica Nucleare, via Dodecaneso 33, 16146 Genova, Italy
On behalf of the ANTARES Collaboration a r t i c l e in f o
a b s t r a c t
Available online 17 September 2010
The ANTARES detector is the world’s first operating deep-sea neutrino telescope. It is located at a depth of 2475 m in the Mediterranean Sea, close to Toulon, France. ANTARES comprises a three-dimensional array of 885 photomultipliers, designed to detect the Cherenkov light produced by neutrino-induced muons passing close to the detector. Since June 2008, the construction of the detector is complete. Various aspects of the detector construction are described and the methods adopted to calibrate in situ the efficiency, timing and positioning of the detector are presented. & 2010 Elsevier B.V. All rights reserved.
Keywords: ANTARES Neutrino telescope
1. Introduction The main goal of neutrino astronomy is to detect neutrinos coming from the most extreme regions of the Universe. The advantage of neutrinos, with respect to other probes such as protons or gammas, is that neutrinos interact only weakly with matter and therefore are not either deviated as protons by galactic magnetic fields, or absorbed by cosmic microwave background as gammas. Neutrinos point back directly to their sources and can therefore tell us information about the most remote objects of the Universe. ANTARES (http://antares.in2p3.fr/) is a deep-sea neutrino telescope, designed for the detection of all flavours of high-energy neutrinos emitted by both galactic (supernova remnants, micro-quasars, etc.) and extragalactic (gamma-ray bursters, active galactic nuclei, etc.) astrophysical sources. Such sources have been observed to emit high-energy gammas and the eventual detection of neutrinos would place important constraints on the nature of these astrophysical accelerators, proving their hadronic nature and contributing to the understanding of the origin of cosmic rays. Due to the extremely low cross-section of neutrino interactions, neutrino detectors need to have very large volumes and to be built in a low background environment. The current neutrino telescopes exploit the idea, proposed by Markov [1], of instrumenting a large volume of water or ice, in order to detect the charged leptons (in particular muons) emerging from CC neutrino interactions.
2. The ANTARES detector The ANTARES detector is located at a depth of 2475 m in the Mediterranean Sea, 42 km from La Seyne sur-Mer in the South of E-mail address: [email protected] 0168-9002/$ - see front matter & 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.nima.2010.09.019
France (42148N, 6110E). It is equipped with 885 optical sensors arranged on 12 flexible lines. Each line comprises up to 25 detection storeys each equipped with three downward-looking 10 in. photomultipliers (PMTs), oriented at 451 from the vertical. Each PMT is installed in an Optical Module (OM) that consists in a 17 in. glass sphere in which the optical connection between the PMT and the glass is assured by an optical gel. The lines are maintained straight by a buoy at the top of the 450 m long line. The spacing between storeys is 14.5 m. The distance between adjacent lines is of the order of 60 m (Fig. 1). The three-dimensional grid of photomultiplier tubes is used to measure the arrival time and position of Cherenkov photons induced by the passage of relativistic charged particles through the sea water. The reconstruction algorithm relies on the characteristic emission angle of the Cherenkov light (about 431) to determine the direction of the muon and hence infer that of the incident neutrino. The accuracy of the direction information allows to distinguish upward-going muons, produced by neutrinos, from the overwhelming background from downwardgoing muons, produced by cosmic ray interactions in the atmosphere above the detector. Installing the detector at great depth serves to attenuate this background and also allows to operate the PMTs in a dark environment. The first detection line was installed in 2006. Five lines have been operating since March 2007. Five more lines were put into operation in December 2007. With the installation of the last two lines in May 2008, the detector construction was completed. An additional line (IL07) contains a set of oceanographic sensors dedicated to the measurement of environmental parameters. An average background pulse rate of 60 kHz is measured on each PMT. This high background comes mainly from the bioluminescent micro-organisms present at the ANTARES site and from the Cherenkov light produced by the electron that comes from the 40K decay present in the salty sea water. On top of
H. Costantini / Nuclear Instruments and Methods in Physics Research A 639 (2011) 26–29
this constant rate, one can observe some bursts that increase the rate up to several hundreds of kHz. Those bursts are produced by macro-bioluminescent organisms passing close to the PMTs. The rate of these bursts is directly correlated with the sea current velocity that is constantly measured with the instrumentation line. The ANTARES data acquisition is based on the all-data-to-shore concept [2], in which all hits above a certain threshold (typically set at a level corresponding to 0.3 of the signal expected from a single photo-electron) are digitized and transmitted to shore. Due to the high background rate it is not possible to write all the data flow, which can easily exceed the rate of 1 GB/s, to disk and therefore the data are filtered onshore by a computer farm that applies different trigger algorithms. A typical trigger rate is 5–10 Hz, dominated by down-going muons. In addition, two multi-messenger triggers are implemented in the ANTARES data acquisition. The first is an external trigger generated by the gamma-ray bursts coordinates network (GCN) that causes all the buffered raw data contained in a 2 min buffer memory to be stored on disk. This offers the potential to apply looser triggers offline on this subset of the data [3]. The second one is an alert which, in case two neutrino-induced events coming from the same region of the sky in a short time window or a very high-energy event are detected, is sent from ANTARES to the Tarot telescope, for an optical follow-up of the potential neutrino source [4].
3. The detector calibration One of the main features of the ANTARES detector is the extremely good angular resolution of 0.31 expected at neutrino energies greater than 10 TeV. This relies on good timing resolution and accuracy of the location of the PMTs. The positions of the PMTs are measured every 2 min with a high-frequency longbaseline acoustic positioning system comprising fixed acoustic emitters-receivers at the bottom of each line and acoustic receivers distributed along a line. After triangulation of the positions of the moving hydrophones, the shape of each line is reconstructed by a global fit based on a model of the physical properties of the line and taking into account the information provided by the tiltmeters and compass sensors located on each storey. The displacement of the PMTs depends on the intensity of
the sea current. For typical currents of few cm/s the displacement of the top storeys is of the order of few meters. The uncertainty on the positions of the PMTs is of the order of 10 cm. Even more crucial is the time calibration of the single PMTs. This is performed with several different systems. A common clock signal is delivered from shore to the whole apparatus. The clock system is also capable of determining the time offsets between the different storeys of the detector. The determination of the remaining residual time offsets within a storey, due to the transit time of the PMT and to the front-end electronics, is obtained before the deployment of the line, in a dark room where groups of OMs are illuminated by a common laser source. The time calibration is performed in the sea by means of a system of optical beacons distributed throughout the detector. During special calibration runs, each beacon illuminates the neighbouring storeys on its line. By measuring the time difference between the optical beacon and the PMT it is possible to determine the relative time offsets (Fig. 2). Since the contribution of the transit time spread of the PMT is negligible due to the high intensity of the LED beacon, the resolution of the time offsets distribution in Fig. 2 gives directly the time resolution due to the electronics. The latter is of the order of 0.5 ns for all PMTs well within the specification to ensure the optimal angular resolution of the detector. The 40K present in the sea water is not only background but also an important calibration tool. The decay 40 K-e ne 40Ca yields an electron with an energy up to 1.3 MeV. This energy exceeds the Cherenkov threshold for electrons in water (0.26 MeV), and is sufficient to produce up to 150 Cherenkov photons. If the decay occurs in the vicinity of a detector storey, coincident signals may be recorded by pairs of PMTs on the storey. The positions of the peaks of the time distributions for different pairs of PMTs in the same storey are used to cross-check the time offsets computed by the optical beacon system. The optical beacon system is also used to obtain information about the optical properties of the water. Flashing the LED beacon it is possible to record the hits on the PMTs as a function of the distance between the led beacon and the PMTs.
6000
5000
number of entries
Fig. 1. The layout of the completed ANTARES detector. The insert shows an image of an optical storey.
27
4000
3000
2000
1000
0 -4
-3
-2
-1
0
1
2
time difference [ns] Fig. 2. Example of time difference distribution between a PMT and a LED OB. The standard deviation of 0.4 ns can be understood as an estimation of the ANTARES time resolution of the electronics.
28
H. Costantini / Nuclear Instruments and Methods in Physics Research A 639 (2011) 26–29
A fit is applied to the hit distribution and an attenuation length of the light in water is obtained that can be considered an upper limit of the absorption length. The big challenge is then to separate the contributions coming from absorption and scattering and this is done using dedicated Monte Carlo simulations and measurements in situ at very low intensity in order to decrease the effect of light scattering. These measurements have started during 2009 to pin down one of the major sources of systematic uncertainty of the experiment. Work is in progress to achieve a precision of the order of 5% on the absorption length determination. Finally important parameters that are needed to compute the reconstruction efficiency are the efficiency of the OM and its angular acceptance, that is the relative efficiency change with respect to the case in which the OM axis is parallel to the Cherenkov photon direction. Different measurements were performed in a water tank. However, the angular acceptance is very hard to determine at large angles in this way, due to the higher light scattering than in the deep sea. A dedicated GEANT4 simulation of the ANTARES OM was therefore performed and a new angular acceptance based on this simulation was adopted.
4. Atmospheric muons and neutrinos The main goal of a neutrino telescope is to detect extraterrestrial neutrinos. Nevertheless the signal observed by ANTARES is dominated by down-going muon events generated by cosmic rays interactions in the atmosphere. The muon flux measured at the ANTARES site is an important test beam to test reconstruction algorithms and understand the systematics of the detector. Two different studies of the vertical depth-intensity relation has been performed. In the first, the attenuation of the muon flux as a function of depth is observed as a reduction in the rate of coincidences between adjacent storeys along the length of the detection lines [5]. This method has the advantage that it does not rely on track reconstruction and allows to test directly the response of the detector. The second method is based on full reconstruction algorithm and the reconstructed zenith angle is converted to an equivalent slant depth through the sea water. Taking into account the known angular distribution of the incident muons, a depth-intensity relation can be extracted [6]. The results are in reasonable agreement with previous measurements as it can be seen in Fig. 3. The large error band is
Fig. 4. Zenith distribution of reconstructed events for the period May 2007– December 2007 and 2008. The Monte Carlo expectations for the atmospheric muon and atmospheric neutrino backgrounds are indicated.
coming mainly from the systematic uncertainty on the angular acceptance at large angles that affects in particular down-going events and on the uncertainty on the determination of the absorption length of light in water. To distinguish muons created by neutrinos from muons created from cosmic rays, it is necessary to select up-going muon events. The angular distribution of the detected events is shown in Fig. 4. This distribution is obtained imposing a cut on the track fit quality of the reconstructed events in order to decrease the amount of misreconstructed down-going events that are reconstructed as up-going particles. A comparison between the experimental data and the Monte Carlo simulation is also reported in Fig. 4. A total of 1062 up-going multi- and singleline neutrino candidates are found, in good agreement with expectations from the atmospheric neutrino background. This distribution refers to the period from May to December 2007 with the five-lines detector and the entire 2008 with the 9–12 lines detector.
5. Conclusions
Fig. 3. Vertical muon flux of atmospheric muons for the five line ANTARES data (black points) as a function of the slant depth. Full squares show the results obtained using the method that does not depend on muon reconstruction. The shaded area represents the systematic uncertainty. The comparison with previous measurements is also reported.
Since the deployment of the first line in 2006 the ANTARES detector is continuously taking data. The detector has been completed in May 2008 and operation and calibration are under control. Maintenance capabilities have also been demonstrated with the recovery, repair and redeployment of some lines. A large sample of neutrinos has been already reconstructed since the beginning of the operations of the detector and the search for astronomical neutrino source has been started. Other analyses related to the search for dark matter and to the combined search for sources using a multi-messenger approach with optical telescopes or gravitational waves detector are underway. ANTARES represents also a multidisciplinary deep-sea research infrastructure, since it provides also a very important data for marine biologists and oceanographers. The successful operation of ANTARES is an important step towards KM3NET [7], a future km3-scale high-energy neutrino observatory and marine science infrastructure proposed for construction in the Mediterranean Sea.
H. Costantini / Nuclear Instruments and Methods in Physics Research A 639 (2011) 26–29
References [1] M.A. Markov, I.M. Zheleznykh, Nucl. Phys. 27 (1961) 385. [2] M. Bouwhuis, Concepts and performance of the Antares data acquisition system, in: ICRC2009, arXiv:0908.0811. [3] M. Bouwhuis, Search for gamma-ray bursts with the Antares neutrino telescope, in: ICRC2009, arXiv:0908.0818.
29
[4] D. Dornic, Search for neutrinos from transient sources with the ANTARES telescope and optical follow-up observations, in: ICRC2009, arXiv:0908.0804. [5] The ANTARES Collaboration, Astropart. Phys. 33 (2010) 86. [6] The ANTARES Collaboration, Astropart. Phys. 34 (2010) 179. [7] Conceptual Design Report for KM3Net Infrastructure, April 2008.
Contents lists available at ScienceDirect
Nuclear Instruments and Methods in Physics Research A journal homepage: www.elsevier.com/locate/nima
The ANTARES deep-sea neutrino telescope: Operation and calibration Heide Costantini Istituto Nazionale di Fisica Nucleare, via Dodecaneso 33, 16146 Genova, Italy
On behalf of the ANTARES Collaboration a r t i c l e in f o
a b s t r a c t
Available online 17 September 2010
The ANTARES detector is the world’s first operating deep-sea neutrino telescope. It is located at a depth of 2475 m in the Mediterranean Sea, close to Toulon, France. ANTARES comprises a three-dimensional array of 885 photomultipliers, designed to detect the Cherenkov light produced by neutrino-induced muons passing close to the detector. Since June 2008, the construction of the detector is complete. Various aspects of the detector construction are described and the methods adopted to calibrate in situ the efficiency, timing and positioning of the detector are presented. & 2010 Elsevier B.V. All rights reserved.
Keywords: ANTARES Neutrino telescope
1. Introduction The main goal of neutrino astronomy is to detect neutrinos coming from the most extreme regions of the Universe. The advantage of neutrinos, with respect to other probes such as protons or gammas, is that neutrinos interact only weakly with matter and therefore are not either deviated as protons by galactic magnetic fields, or absorbed by cosmic microwave background as gammas. Neutrinos point back directly to their sources and can therefore tell us information about the most remote objects of the Universe. ANTARES (http://antares.in2p3.fr/) is a deep-sea neutrino telescope, designed for the detection of all flavours of high-energy neutrinos emitted by both galactic (supernova remnants, micro-quasars, etc.) and extragalactic (gamma-ray bursters, active galactic nuclei, etc.) astrophysical sources. Such sources have been observed to emit high-energy gammas and the eventual detection of neutrinos would place important constraints on the nature of these astrophysical accelerators, proving their hadronic nature and contributing to the understanding of the origin of cosmic rays. Due to the extremely low cross-section of neutrino interactions, neutrino detectors need to have very large volumes and to be built in a low background environment. The current neutrino telescopes exploit the idea, proposed by Markov [1], of instrumenting a large volume of water or ice, in order to detect the charged leptons (in particular muons) emerging from CC neutrino interactions.
2. The ANTARES detector The ANTARES detector is located at a depth of 2475 m in the Mediterranean Sea, 42 km from La Seyne sur-Mer in the South of E-mail address: [email protected] 0168-9002/$ - see front matter & 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.nima.2010.09.019
France (42148N, 6110E). It is equipped with 885 optical sensors arranged on 12 flexible lines. Each line comprises up to 25 detection storeys each equipped with three downward-looking 10 in. photomultipliers (PMTs), oriented at 451 from the vertical. Each PMT is installed in an Optical Module (OM) that consists in a 17 in. glass sphere in which the optical connection between the PMT and the glass is assured by an optical gel. The lines are maintained straight by a buoy at the top of the 450 m long line. The spacing between storeys is 14.5 m. The distance between adjacent lines is of the order of 60 m (Fig. 1). The three-dimensional grid of photomultiplier tubes is used to measure the arrival time and position of Cherenkov photons induced by the passage of relativistic charged particles through the sea water. The reconstruction algorithm relies on the characteristic emission angle of the Cherenkov light (about 431) to determine the direction of the muon and hence infer that of the incident neutrino. The accuracy of the direction information allows to distinguish upward-going muons, produced by neutrinos, from the overwhelming background from downwardgoing muons, produced by cosmic ray interactions in the atmosphere above the detector. Installing the detector at great depth serves to attenuate this background and also allows to operate the PMTs in a dark environment. The first detection line was installed in 2006. Five lines have been operating since March 2007. Five more lines were put into operation in December 2007. With the installation of the last two lines in May 2008, the detector construction was completed. An additional line (IL07) contains a set of oceanographic sensors dedicated to the measurement of environmental parameters. An average background pulse rate of 60 kHz is measured on each PMT. This high background comes mainly from the bioluminescent micro-organisms present at the ANTARES site and from the Cherenkov light produced by the electron that comes from the 40K decay present in the salty sea water. On top of
H. Costantini / Nuclear Instruments and Methods in Physics Research A 639 (2011) 26–29
this constant rate, one can observe some bursts that increase the rate up to several hundreds of kHz. Those bursts are produced by macro-bioluminescent organisms passing close to the PMTs. The rate of these bursts is directly correlated with the sea current velocity that is constantly measured with the instrumentation line. The ANTARES data acquisition is based on the all-data-to-shore concept [2], in which all hits above a certain threshold (typically set at a level corresponding to 0.3 of the signal expected from a single photo-electron) are digitized and transmitted to shore. Due to the high background rate it is not possible to write all the data flow, which can easily exceed the rate of 1 GB/s, to disk and therefore the data are filtered onshore by a computer farm that applies different trigger algorithms. A typical trigger rate is 5–10 Hz, dominated by down-going muons. In addition, two multi-messenger triggers are implemented in the ANTARES data acquisition. The first is an external trigger generated by the gamma-ray bursts coordinates network (GCN) that causes all the buffered raw data contained in a 2 min buffer memory to be stored on disk. This offers the potential to apply looser triggers offline on this subset of the data [3]. The second one is an alert which, in case two neutrino-induced events coming from the same region of the sky in a short time window or a very high-energy event are detected, is sent from ANTARES to the Tarot telescope, for an optical follow-up of the potential neutrino source [4].
3. The detector calibration One of the main features of the ANTARES detector is the extremely good angular resolution of 0.31 expected at neutrino energies greater than 10 TeV. This relies on good timing resolution and accuracy of the location of the PMTs. The positions of the PMTs are measured every 2 min with a high-frequency longbaseline acoustic positioning system comprising fixed acoustic emitters-receivers at the bottom of each line and acoustic receivers distributed along a line. After triangulation of the positions of the moving hydrophones, the shape of each line is reconstructed by a global fit based on a model of the physical properties of the line and taking into account the information provided by the tiltmeters and compass sensors located on each storey. The displacement of the PMTs depends on the intensity of
the sea current. For typical currents of few cm/s the displacement of the top storeys is of the order of few meters. The uncertainty on the positions of the PMTs is of the order of 10 cm. Even more crucial is the time calibration of the single PMTs. This is performed with several different systems. A common clock signal is delivered from shore to the whole apparatus. The clock system is also capable of determining the time offsets between the different storeys of the detector. The determination of the remaining residual time offsets within a storey, due to the transit time of the PMT and to the front-end electronics, is obtained before the deployment of the line, in a dark room where groups of OMs are illuminated by a common laser source. The time calibration is performed in the sea by means of a system of optical beacons distributed throughout the detector. During special calibration runs, each beacon illuminates the neighbouring storeys on its line. By measuring the time difference between the optical beacon and the PMT it is possible to determine the relative time offsets (Fig. 2). Since the contribution of the transit time spread of the PMT is negligible due to the high intensity of the LED beacon, the resolution of the time offsets distribution in Fig. 2 gives directly the time resolution due to the electronics. The latter is of the order of 0.5 ns for all PMTs well within the specification to ensure the optimal angular resolution of the detector. The 40K present in the sea water is not only background but also an important calibration tool. The decay 40 K-e ne 40Ca yields an electron with an energy up to 1.3 MeV. This energy exceeds the Cherenkov threshold for electrons in water (0.26 MeV), and is sufficient to produce up to 150 Cherenkov photons. If the decay occurs in the vicinity of a detector storey, coincident signals may be recorded by pairs of PMTs on the storey. The positions of the peaks of the time distributions for different pairs of PMTs in the same storey are used to cross-check the time offsets computed by the optical beacon system. The optical beacon system is also used to obtain information about the optical properties of the water. Flashing the LED beacon it is possible to record the hits on the PMTs as a function of the distance between the led beacon and the PMTs.
6000
5000
number of entries
Fig. 1. The layout of the completed ANTARES detector. The insert shows an image of an optical storey.
27
4000
3000
2000
1000
0 -4
-3
-2
-1
0
1
2
time difference [ns] Fig. 2. Example of time difference distribution between a PMT and a LED OB. The standard deviation of 0.4 ns can be understood as an estimation of the ANTARES time resolution of the electronics.
28
H. Costantini / Nuclear Instruments and Methods in Physics Research A 639 (2011) 26–29
A fit is applied to the hit distribution and an attenuation length of the light in water is obtained that can be considered an upper limit of the absorption length. The big challenge is then to separate the contributions coming from absorption and scattering and this is done using dedicated Monte Carlo simulations and measurements in situ at very low intensity in order to decrease the effect of light scattering. These measurements have started during 2009 to pin down one of the major sources of systematic uncertainty of the experiment. Work is in progress to achieve a precision of the order of 5% on the absorption length determination. Finally important parameters that are needed to compute the reconstruction efficiency are the efficiency of the OM and its angular acceptance, that is the relative efficiency change with respect to the case in which the OM axis is parallel to the Cherenkov photon direction. Different measurements were performed in a water tank. However, the angular acceptance is very hard to determine at large angles in this way, due to the higher light scattering than in the deep sea. A dedicated GEANT4 simulation of the ANTARES OM was therefore performed and a new angular acceptance based on this simulation was adopted.
4. Atmospheric muons and neutrinos The main goal of a neutrino telescope is to detect extraterrestrial neutrinos. Nevertheless the signal observed by ANTARES is dominated by down-going muon events generated by cosmic rays interactions in the atmosphere. The muon flux measured at the ANTARES site is an important test beam to test reconstruction algorithms and understand the systematics of the detector. Two different studies of the vertical depth-intensity relation has been performed. In the first, the attenuation of the muon flux as a function of depth is observed as a reduction in the rate of coincidences between adjacent storeys along the length of the detection lines [5]. This method has the advantage that it does not rely on track reconstruction and allows to test directly the response of the detector. The second method is based on full reconstruction algorithm and the reconstructed zenith angle is converted to an equivalent slant depth through the sea water. Taking into account the known angular distribution of the incident muons, a depth-intensity relation can be extracted [6]. The results are in reasonable agreement with previous measurements as it can be seen in Fig. 3. The large error band is
Fig. 4. Zenith distribution of reconstructed events for the period May 2007– December 2007 and 2008. The Monte Carlo expectations for the atmospheric muon and atmospheric neutrino backgrounds are indicated.
coming mainly from the systematic uncertainty on the angular acceptance at large angles that affects in particular down-going events and on the uncertainty on the determination of the absorption length of light in water. To distinguish muons created by neutrinos from muons created from cosmic rays, it is necessary to select up-going muon events. The angular distribution of the detected events is shown in Fig. 4. This distribution is obtained imposing a cut on the track fit quality of the reconstructed events in order to decrease the amount of misreconstructed down-going events that are reconstructed as up-going particles. A comparison between the experimental data and the Monte Carlo simulation is also reported in Fig. 4. A total of 1062 up-going multi- and singleline neutrino candidates are found, in good agreement with expectations from the atmospheric neutrino background. This distribution refers to the period from May to December 2007 with the five-lines detector and the entire 2008 with the 9–12 lines detector.
5. Conclusions
Fig. 3. Vertical muon flux of atmospheric muons for the five line ANTARES data (black points) as a function of the slant depth. Full squares show the results obtained using the method that does not depend on muon reconstruction. The shaded area represents the systematic uncertainty. The comparison with previous measurements is also reported.
Since the deployment of the first line in 2006 the ANTARES detector is continuously taking data. The detector has been completed in May 2008 and operation and calibration are under control. Maintenance capabilities have also been demonstrated with the recovery, repair and redeployment of some lines. A large sample of neutrinos has been already reconstructed since the beginning of the operations of the detector and the search for astronomical neutrino source has been started. Other analyses related to the search for dark matter and to the combined search for sources using a multi-messenger approach with optical telescopes or gravitational waves detector are underway. ANTARES represents also a multidisciplinary deep-sea research infrastructure, since it provides also a very important data for marine biologists and oceanographers. The successful operation of ANTARES is an important step towards KM3NET [7], a future km3-scale high-energy neutrino observatory and marine science infrastructure proposed for construction in the Mediterranean Sea.
H. Costantini / Nuclear Instruments and Methods in Physics Research A 639 (2011) 26–29
References [1] M.A. Markov, I.M. Zheleznykh, Nucl. Phys. 27 (1961) 385. [2] M. Bouwhuis, Concepts and performance of the Antares data acquisition system, in: ICRC2009, arXiv:0908.0811. [3] M. Bouwhuis, Search for gamma-ray bursts with the Antares neutrino telescope, in: ICRC2009, arXiv:0908.0818.
29
[4] D. Dornic, Search for neutrinos from transient sources with the ANTARES telescope and optical follow-up observations, in: ICRC2009, arXiv:0908.0804. [5] The ANTARES Collaboration, Astropart. Phys. 33 (2010) 86. [6] The ANTARES Collaboration, Astropart. Phys. 34 (2010) 179. [7] Conceptual Design Report for KM3Net Infrastructure, April 2008.