- Email: [email protected]
Data from the ANTARES Neutrino Telescope
ARTICLE IN PRESS
Nuclear Instruments and Methods in Physics Research A 588 (2008) 80–85 www.elsevier.com/locate/nima
Data from the ANTARES Neutrino Telescope J. Carr Centre de Physique de Particules de Marseille, 13288 Marseille, France On behalf of ANTARES Collaboration Available online 12 January 2008
Abstract This article shows some of the first data from the ANTARES Neutrino Telescope. At the present time (summer 2007) five detector lines are in operation making ANTARES the largest Neutrino Telescope in the northern hemisphere. This report describes the ANTARES project, gives the present status as well as some of the early results obtained. r 2008 Elsevier B.V. All rights reserved. Keywords: Neutrino astronomy; ANTARES; Neutrino telescope; Deep sea technology
1. Introduction Since January 2007 the ANTARES Neutrino Telescope has been operating with 5/12 lines functional making it the largest neutrino telescope in the northern hemisphere. This article describes the structure of the ANTARES detector and the various development steps to achieve the successful construction of the system. Some examples of the detector calibration are given together with the first data on reconstructed neutrinos.
2. Design of ANTARES Neutrino Telescope An artist’s impression of the layout of the ANTARES Neutrino Telescope is shown in Fig. 1. The detector consists of 12 lines each with a total height of 450 m which are weighted to the seabed and held nearly vertical by syntactic-foam buoys at the top. Fig. 2 illustrates the components within a typical line. The lines have a total of 75 photomultipliers (PMTs) housed in glass spheres, referred to as optical modules (OM) [1], destined to detect Cherenkov light from charged particle tracks in the sea water. The seabed at the site is at a depth of 2500 m and OM are positioned at depths between 2400 and 2000 m. E-mail address: [email protected] 0168-9002/$ - see front matter r 2008 Elsevier B.V. All rights reserved. doi:10.1016/j.nima.2008.01.010
The lines are flexible and so move in the sea current, with movements being a few meters at the top for a typical sea current of 5 cm/s. The positions of the OM are measured with a system of acoustic transponders and receivers at discrete positions on the line and on the seabed, together with tiltmeters and compasses on each storey of the line. The positioning system gives a real time measurement, typically once every few minutes, of the position of every OM with a precision better then 10 cm in space. The default readout mode of ANTARES is the transmission of the time and amplitude of any PMT signal above a threshold corresponding to 13 of a photoelectron for each optical module. Time measurements are referenced to a master reference clock signal distributed to each storey from shore. All signals are sent to shore and treated in a computer farm to find hit patterns corresponding to muon tracks or other physics events producing light in the water. The grouping of three OM in a storey allows local coincidences to be made for this pattern finding and also in certain circumstances local triggers to be formed to reduce the readout rate. In addition the front end electronics allows a more detailed readout of the PMT signal than the standard time and amplitude mode. With this detailed readout it is possible to sample the full waveform of the signal with 128 samples separated by 2 ns, enabling special calibration studies of the electronics.
ARTICLE IN PRESS J. Carr / Nuclear Instruments and Methods in Physics Research A 588 (2008) 80–85
Fig. 1. Artist’s impression of the ANTARES Neutrino Telescope on the sea floor, showing the detector lines, the seabed interlinks cables, the junction box and the cable to the shore. In this illustration for clarity, the number of storeys per line is reduced and items are not drawn to scale.
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every fifth storey and the combined link output is sent on a particular wavelength to a dense wavelength division multiplexing system in an electronics container, the String Control Module (SCM), at the bottom of each line. In the SCM the outputs from the five MLCMs along the line are multiplexed on to one pair of optical fibers. These fibers are then connected to a junction box (JB) on the seabed via interlink cables. In JB the outputs from up to 16 lines are gathered onto a 48 fiber electro-optical submarine cable, the Main Electro-Optical Cable (MEOC), and sent to the experiment shore station in the town of La Seyne-sur-Mer, in France. The optical links between each MLCM and the shore station are connected using only passive components. The electrical supply system has a similar architecture to the readout system. The submarine cable supplies 4400 V, 10 A AC to a transformer in JB. The 16 independent secondary outputs from the transformer provide 500 V, 4 A AC to the lines via the interlink cables. At the base of each line a String Power Module (SPM) power supply shares the same container as the SCM. The SPM distributes 400 V DC to the MLCMs and LCMs in the line each of which contains a Local Power Box (LPB) to provide the various low voltages required by each electronics card. The 45 km undersea MEOC links the detector to the shore station in La Seyne-sur-Mer which houses the computer farm for the onshore event filtering. After this selection the data are sent via a standard telephone network data link to be recorded at a computer center in Lyon. 3. Early ANTARES activities and test lines
Fig. 2. Schematic of an ANTARES detector line. For clarity, only 4 of the 25 storeys are shown and the electromagnetic cable lengths are not drawn to scale.
The readout architecture of the detector has several levels of multiplexing of the PMT signals. The first level is in the Local Control Module (LCM) in each storey of the detector where the analog electrical outputs of the PMTs are digitized in a custom built ASIC chip, the Analogue Ring Sampler (ARS) before being treated by a data acquisition card, containing an FPGA and microprocessor, which outputs the multiplexed signals of the three local OM on an Ethernet optical link. The links from five storeys, forming a Sector, are combined in an Ethernet switch in the Master Local Control Module (MLCM) at
In 1996 the ANTARES Collaboration started R&D activities towards the construction of a neutrino telescope. The first operations were the deployment and recovery of autonomous mooring lines to measure the properties of the water and environment at the ANTARES site which is located off the French coast at 421480 N and 61100 E at a depth of 2500 m. In these site evaluation campaigns [2,3], comprising more than 60 line deployments, extensive measurements were made of light background from bioluminescence, bio-deposition, sedimentation and light attenuation. The earliest test line in the ANTARES program, which was connected to a readout system on shore, was deployed in November 1999 and is referred to as the ‘‘Demonstrator Line’’. This line used an old, existing, undersea cable donated by France Telecom, connecting the line to a recording station in Marseille. Located on a special site near Marseille at a depth of 1200 m, the line was operated for a few months and proved various concepts of the ANTARES design, in particular the acoustic positioning system, and included reconstruction of cosmic ray muons with seven OM [4]. In 2001 the construction of the actual detector started with the deployment of a new cable between the final
ARTICLE IN PRESS 82
J. Carr / Nuclear Instruments and Methods in Physics Research A 588 (2008) 80–85
ANTARES site and the shore station in La Seyne-sur-Mer. This cable, the present MEOC, was deployed on the seabed in November 2001, initially with only a loop-back container at the sea end and in November 2002 the end of the cable was brought to the surface, connected to JB and redeployed. Since this date the battery operated slow control in JB has sent to shore measurements of various parameters in the housing showing perfect operation of the MEOC and JB system for more than four years. Fig. 3 shows a time record of environment data inside JB. During 2003, prototypes approaching the final technology of the ANTARES detector were operated. Two lines were deployed and connected between November 2002 and March 2003: the ‘‘MIL’’, an instrumentation line and the ‘‘PSL’’, a short optical detector line with 15 OM. These lines, which were operated in situ until May and July 2003 respectively, again proved the validity of various aspects of the design but indicated as well certain problems with loss of optical transmission in the line cables and leaks in the cables and containers. Nevertheless, the PSL was able to measure the counting rates in OM, in particular the rates of bioluminescence, over a period of 4 months. After the experiences of the MIL and PSL lines some significant changes were made to the detector design and a line incorporating these changes, the ‘‘MILOM’’ was deployed in the sea from the ship CASTOR on 18 March 2005 with the connection using the Remote Operated Vehicle VICTOR on 12 April 2005. The successful operation of this line for several months in 2005 is described in Ref. [5].
dates since March 2006 using the ship CASTOR and connected on the seabed at different dates using the submarine Nautile or the ROV Victor of IFREMER. The deployment and connections of the full detector with 12 lines is expected to be completed by spring 2008.
5. Calibration data At present in ANTARES, as in the early stages of any experiment, the main analysis activities are towards the
4. Status of ANTARES detector Since 29 January, five out of the planned 12 ANTARES lines are operational. Fig. 4 indicates the seabed layout of the detector lines, showing the five connected to JB with interlink cables as well as the other three in place in summer 2007. The lines have been deployed at various
Fig. 4. Seabed layout of the ANTARES detector. The lines indicated in red were in place in summer 2007 with 5 among them connected to the junction box.
Fig. 3. Data on humidity and temperature inside the junction box during more than four years of operation.
ARTICLE IN PRESS J. Carr / Nuclear Instruments and Methods in Physics Research A 588 (2008) 80–85
calibration of the apparatus. The main parameters in ANTARES requiring calibration are the timing and position of OM. The signal amplitude is also important. An example of the data from the acoustic positioning system is shown in Fig. 5. This plot shows the displacement in the horizontal plane of the five hydrophones at different heights along the line. The detailed analysis of this data is still in progress, but the width of the traces in Fig. 5 already demonstrates that the statistical precision of the acoustics positioning system is well within the 10 cm required. The timing calibration of OM is made initially during the line assembly with a system of fiber optics distributing light pulses simultaneously to each optical module. In the sea this initial timing calibration is controlled and if necessary adjusted using a system of optical beacons [6] on the detector lines. Fig. 6 shows some results from this system. The lower and upper plots show the time distributions for two OM at respective distances 70 and 150 m from an optical beacon in a different line. For the nearer OM the time distribution is 0.7 ns indicating the timing precision of the electronics for many incident photons while the width of the distribution for a bigger separation contains contributions from the PMT transit time spread and propagation in the sea water. A further check on the timing of OM is made using time coincidences between adjacent modules in the same line storey. The natural radioactivity of potassium 40 in the sea salt provides an excellent calibration tool. Fig. 7 shows one example of the time difference between signals in adjacent OM. The peak close to zero in this plot is due to 40K. The offsets from zero of such peaks allow a calibration of the OM timing and the integral rate of 40K provides a calibration of the efficiency of OM. The later efficiency calibration must rely on a Monte Carlo simulation which with nominal efficiencies gives a rate of 12 Hz compared to the 13 Hz for the example in Fig. 7.
Fig. 5. The displacement in the horizontal plane of the five hydrophones on different storeys at different heights in line 4. The different colors give the displacements of the different storeys as indicated in the figure.
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Fig. 6. Data from the optical beacon system. For an optical beacon on one line, the bottom plot shows the timing distribution of light arriving on an adjacent line at the same height with a separation between beacon and optical module 70 m. The top plot shows the time distribution for an optical module higher up the second line with a distance from the beacon of 150 m. Both distributions have been centered at zero.
Fig. 7. Time differences from coincidences on two adjacent optical modules showing the signal from 40K decay.
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J. Carr / Nuclear Instruments and Methods in Physics Research A 588 (2008) 80–85
Fig. 10. Zenith angle distribution for data taken between February and May 2007. Fig. 8. Active days of data taking as a function of calendar date since the connection of the first complete line.
of 1 line; 2 line and 5 line operation. The slope of the line illustrates the overall data taking efficiency, which was around 70% in spring 2007. At present a number of algorithms for reconstruction are being developed with the collaboration. One of these algorithms was developed in the thesis work of Ref. [7] using Monte Carlo simulations performed before the operation of the detector. This algorithm is applied to the data with exactly the same cuts as developed on the simulations. Fig. 9 shows an event reconstructed using this algorithm, while Fig. 10 shows the zenith angle distribution from the first months of 5 line operation. The reconstruction algorithm is preliminary and uses nominal detector geometry with no alignment. The zenith angular distribution of Fig. 10 illustrates clearly the separation between upward and downward going tracks. The hypothesis that the majority of the upward going tracks are due to neutrino interaction is being evaluated in Monte Carlo simulations of the detector response. 7. Conclusions
Fig. 9. The first candidate neutrino event seen with the 5-line detector.
6. First results from data with five lines The ANTARES detector has been increasing in size as extra lines have been connected since the connection of the first complete line in March 2005. Fig. 8 shows the number of active days of data taking, taking into account all losses since the connection of this first line and shows the periods
The ANTARES Neutrino Telescope is nearing completion after a long period of development and construction. Clear evidence for the excellent precision of the detector components can be seen in the first data. Detailed analysis of the first data is in progress, which promises to prove the superior properties of undersea neutrino telescopes. References [1] P. Amram, ANTARES Collaboration, et al., Nucl. Instr. and Meth. A 484 (2002) 369.
ARTICLE IN PRESS J. Carr / Nuclear Instruments and Methods in Physics Research A 588 (2008) 80–85 [2] P. Amram, ANTARES Collaboration, et al., Astrop. Phys. 19 (2003) 253. [3] P. Amram, ANTARES Collaboration, et al., Astrop. Phys. 13 (2000) 127. [4] A. Kouchner, Thesis /http://antares.in2p3.fr/Publications/thesis/ 2001/antoine-kouchner-phd.ps.gzS.
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[5] J.A. Aguilar, ANTARES Collaboration, et al., Astrop. Phys. 26 (2006) 314. [6] M. Ageron, et al., Nucl. Instr. and Meth. A 578 (2007) 498. [7] Track Reconstruction and Point Source Searches with ANTARES, Aart Heijboer, Universiteit van Amsterdam, The Netherlands, 2004.
Nuclear Instruments and Methods in Physics Research A 588 (2008) 80–85 www.elsevier.com/locate/nima
Data from the ANTARES Neutrino Telescope J. Carr Centre de Physique de Particules de Marseille, 13288 Marseille, France On behalf of ANTARES Collaboration Available online 12 January 2008
Abstract This article shows some of the first data from the ANTARES Neutrino Telescope. At the present time (summer 2007) five detector lines are in operation making ANTARES the largest Neutrino Telescope in the northern hemisphere. This report describes the ANTARES project, gives the present status as well as some of the early results obtained. r 2008 Elsevier B.V. All rights reserved. Keywords: Neutrino astronomy; ANTARES; Neutrino telescope; Deep sea technology
1. Introduction Since January 2007 the ANTARES Neutrino Telescope has been operating with 5/12 lines functional making it the largest neutrino telescope in the northern hemisphere. This article describes the structure of the ANTARES detector and the various development steps to achieve the successful construction of the system. Some examples of the detector calibration are given together with the first data on reconstructed neutrinos.
2. Design of ANTARES Neutrino Telescope An artist’s impression of the layout of the ANTARES Neutrino Telescope is shown in Fig. 1. The detector consists of 12 lines each with a total height of 450 m which are weighted to the seabed and held nearly vertical by syntactic-foam buoys at the top. Fig. 2 illustrates the components within a typical line. The lines have a total of 75 photomultipliers (PMTs) housed in glass spheres, referred to as optical modules (OM) [1], destined to detect Cherenkov light from charged particle tracks in the sea water. The seabed at the site is at a depth of 2500 m and OM are positioned at depths between 2400 and 2000 m. E-mail address: [email protected] 0168-9002/$ - see front matter r 2008 Elsevier B.V. All rights reserved. doi:10.1016/j.nima.2008.01.010
The lines are flexible and so move in the sea current, with movements being a few meters at the top for a typical sea current of 5 cm/s. The positions of the OM are measured with a system of acoustic transponders and receivers at discrete positions on the line and on the seabed, together with tiltmeters and compasses on each storey of the line. The positioning system gives a real time measurement, typically once every few minutes, of the position of every OM with a precision better then 10 cm in space. The default readout mode of ANTARES is the transmission of the time and amplitude of any PMT signal above a threshold corresponding to 13 of a photoelectron for each optical module. Time measurements are referenced to a master reference clock signal distributed to each storey from shore. All signals are sent to shore and treated in a computer farm to find hit patterns corresponding to muon tracks or other physics events producing light in the water. The grouping of three OM in a storey allows local coincidences to be made for this pattern finding and also in certain circumstances local triggers to be formed to reduce the readout rate. In addition the front end electronics allows a more detailed readout of the PMT signal than the standard time and amplitude mode. With this detailed readout it is possible to sample the full waveform of the signal with 128 samples separated by 2 ns, enabling special calibration studies of the electronics.
ARTICLE IN PRESS J. Carr / Nuclear Instruments and Methods in Physics Research A 588 (2008) 80–85
Fig. 1. Artist’s impression of the ANTARES Neutrino Telescope on the sea floor, showing the detector lines, the seabed interlinks cables, the junction box and the cable to the shore. In this illustration for clarity, the number of storeys per line is reduced and items are not drawn to scale.
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every fifth storey and the combined link output is sent on a particular wavelength to a dense wavelength division multiplexing system in an electronics container, the String Control Module (SCM), at the bottom of each line. In the SCM the outputs from the five MLCMs along the line are multiplexed on to one pair of optical fibers. These fibers are then connected to a junction box (JB) on the seabed via interlink cables. In JB the outputs from up to 16 lines are gathered onto a 48 fiber electro-optical submarine cable, the Main Electro-Optical Cable (MEOC), and sent to the experiment shore station in the town of La Seyne-sur-Mer, in France. The optical links between each MLCM and the shore station are connected using only passive components. The electrical supply system has a similar architecture to the readout system. The submarine cable supplies 4400 V, 10 A AC to a transformer in JB. The 16 independent secondary outputs from the transformer provide 500 V, 4 A AC to the lines via the interlink cables. At the base of each line a String Power Module (SPM) power supply shares the same container as the SCM. The SPM distributes 400 V DC to the MLCMs and LCMs in the line each of which contains a Local Power Box (LPB) to provide the various low voltages required by each electronics card. The 45 km undersea MEOC links the detector to the shore station in La Seyne-sur-Mer which houses the computer farm for the onshore event filtering. After this selection the data are sent via a standard telephone network data link to be recorded at a computer center in Lyon. 3. Early ANTARES activities and test lines
Fig. 2. Schematic of an ANTARES detector line. For clarity, only 4 of the 25 storeys are shown and the electromagnetic cable lengths are not drawn to scale.
The readout architecture of the detector has several levels of multiplexing of the PMT signals. The first level is in the Local Control Module (LCM) in each storey of the detector where the analog electrical outputs of the PMTs are digitized in a custom built ASIC chip, the Analogue Ring Sampler (ARS) before being treated by a data acquisition card, containing an FPGA and microprocessor, which outputs the multiplexed signals of the three local OM on an Ethernet optical link. The links from five storeys, forming a Sector, are combined in an Ethernet switch in the Master Local Control Module (MLCM) at
In 1996 the ANTARES Collaboration started R&D activities towards the construction of a neutrino telescope. The first operations were the deployment and recovery of autonomous mooring lines to measure the properties of the water and environment at the ANTARES site which is located off the French coast at 421480 N and 61100 E at a depth of 2500 m. In these site evaluation campaigns [2,3], comprising more than 60 line deployments, extensive measurements were made of light background from bioluminescence, bio-deposition, sedimentation and light attenuation. The earliest test line in the ANTARES program, which was connected to a readout system on shore, was deployed in November 1999 and is referred to as the ‘‘Demonstrator Line’’. This line used an old, existing, undersea cable donated by France Telecom, connecting the line to a recording station in Marseille. Located on a special site near Marseille at a depth of 1200 m, the line was operated for a few months and proved various concepts of the ANTARES design, in particular the acoustic positioning system, and included reconstruction of cosmic ray muons with seven OM [4]. In 2001 the construction of the actual detector started with the deployment of a new cable between the final
ARTICLE IN PRESS 82
J. Carr / Nuclear Instruments and Methods in Physics Research A 588 (2008) 80–85
ANTARES site and the shore station in La Seyne-sur-Mer. This cable, the present MEOC, was deployed on the seabed in November 2001, initially with only a loop-back container at the sea end and in November 2002 the end of the cable was brought to the surface, connected to JB and redeployed. Since this date the battery operated slow control in JB has sent to shore measurements of various parameters in the housing showing perfect operation of the MEOC and JB system for more than four years. Fig. 3 shows a time record of environment data inside JB. During 2003, prototypes approaching the final technology of the ANTARES detector were operated. Two lines were deployed and connected between November 2002 and March 2003: the ‘‘MIL’’, an instrumentation line and the ‘‘PSL’’, a short optical detector line with 15 OM. These lines, which were operated in situ until May and July 2003 respectively, again proved the validity of various aspects of the design but indicated as well certain problems with loss of optical transmission in the line cables and leaks in the cables and containers. Nevertheless, the PSL was able to measure the counting rates in OM, in particular the rates of bioluminescence, over a period of 4 months. After the experiences of the MIL and PSL lines some significant changes were made to the detector design and a line incorporating these changes, the ‘‘MILOM’’ was deployed in the sea from the ship CASTOR on 18 March 2005 with the connection using the Remote Operated Vehicle VICTOR on 12 April 2005. The successful operation of this line for several months in 2005 is described in Ref. [5].
dates since March 2006 using the ship CASTOR and connected on the seabed at different dates using the submarine Nautile or the ROV Victor of IFREMER. The deployment and connections of the full detector with 12 lines is expected to be completed by spring 2008.
5. Calibration data At present in ANTARES, as in the early stages of any experiment, the main analysis activities are towards the
4. Status of ANTARES detector Since 29 January, five out of the planned 12 ANTARES lines are operational. Fig. 4 indicates the seabed layout of the detector lines, showing the five connected to JB with interlink cables as well as the other three in place in summer 2007. The lines have been deployed at various
Fig. 4. Seabed layout of the ANTARES detector. The lines indicated in red were in place in summer 2007 with 5 among them connected to the junction box.
Fig. 3. Data on humidity and temperature inside the junction box during more than four years of operation.
ARTICLE IN PRESS J. Carr / Nuclear Instruments and Methods in Physics Research A 588 (2008) 80–85
calibration of the apparatus. The main parameters in ANTARES requiring calibration are the timing and position of OM. The signal amplitude is also important. An example of the data from the acoustic positioning system is shown in Fig. 5. This plot shows the displacement in the horizontal plane of the five hydrophones at different heights along the line. The detailed analysis of this data is still in progress, but the width of the traces in Fig. 5 already demonstrates that the statistical precision of the acoustics positioning system is well within the 10 cm required. The timing calibration of OM is made initially during the line assembly with a system of fiber optics distributing light pulses simultaneously to each optical module. In the sea this initial timing calibration is controlled and if necessary adjusted using a system of optical beacons [6] on the detector lines. Fig. 6 shows some results from this system. The lower and upper plots show the time distributions for two OM at respective distances 70 and 150 m from an optical beacon in a different line. For the nearer OM the time distribution is 0.7 ns indicating the timing precision of the electronics for many incident photons while the width of the distribution for a bigger separation contains contributions from the PMT transit time spread and propagation in the sea water. A further check on the timing of OM is made using time coincidences between adjacent modules in the same line storey. The natural radioactivity of potassium 40 in the sea salt provides an excellent calibration tool. Fig. 7 shows one example of the time difference between signals in adjacent OM. The peak close to zero in this plot is due to 40K. The offsets from zero of such peaks allow a calibration of the OM timing and the integral rate of 40K provides a calibration of the efficiency of OM. The later efficiency calibration must rely on a Monte Carlo simulation which with nominal efficiencies gives a rate of 12 Hz compared to the 13 Hz for the example in Fig. 7.
Fig. 5. The displacement in the horizontal plane of the five hydrophones on different storeys at different heights in line 4. The different colors give the displacements of the different storeys as indicated in the figure.
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Fig. 6. Data from the optical beacon system. For an optical beacon on one line, the bottom plot shows the timing distribution of light arriving on an adjacent line at the same height with a separation between beacon and optical module 70 m. The top plot shows the time distribution for an optical module higher up the second line with a distance from the beacon of 150 m. Both distributions have been centered at zero.
Fig. 7. Time differences from coincidences on two adjacent optical modules showing the signal from 40K decay.
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J. Carr / Nuclear Instruments and Methods in Physics Research A 588 (2008) 80–85
Fig. 10. Zenith angle distribution for data taken between February and May 2007. Fig. 8. Active days of data taking as a function of calendar date since the connection of the first complete line.
of 1 line; 2 line and 5 line operation. The slope of the line illustrates the overall data taking efficiency, which was around 70% in spring 2007. At present a number of algorithms for reconstruction are being developed with the collaboration. One of these algorithms was developed in the thesis work of Ref. [7] using Monte Carlo simulations performed before the operation of the detector. This algorithm is applied to the data with exactly the same cuts as developed on the simulations. Fig. 9 shows an event reconstructed using this algorithm, while Fig. 10 shows the zenith angle distribution from the first months of 5 line operation. The reconstruction algorithm is preliminary and uses nominal detector geometry with no alignment. The zenith angular distribution of Fig. 10 illustrates clearly the separation between upward and downward going tracks. The hypothesis that the majority of the upward going tracks are due to neutrino interaction is being evaluated in Monte Carlo simulations of the detector response. 7. Conclusions
Fig. 9. The first candidate neutrino event seen with the 5-line detector.
6. First results from data with five lines The ANTARES detector has been increasing in size as extra lines have been connected since the connection of the first complete line in March 2005. Fig. 8 shows the number of active days of data taking, taking into account all losses since the connection of this first line and shows the periods
The ANTARES Neutrino Telescope is nearing completion after a long period of development and construction. Clear evidence for the excellent precision of the detector components can be seen in the first data. Detailed analysis of the first data is in progress, which promises to prove the superior properties of undersea neutrino telescopes. References [1] P. Amram, ANTARES Collaboration, et al., Nucl. Instr. and Meth. A 484 (2002) 369.
ARTICLE IN PRESS J. Carr / Nuclear Instruments and Methods in Physics Research A 588 (2008) 80–85 [2] P. Amram, ANTARES Collaboration, et al., Astrop. Phys. 19 (2003) 253. [3] P. Amram, ANTARES Collaboration, et al., Astrop. Phys. 13 (2000) 127. [4] A. Kouchner, Thesis /http://antares.in2p3.fr/Publications/thesis/ 2001/antoine-kouchner-phd.ps.gzS.
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[5] J.A. Aguilar, ANTARES Collaboration, et al., Astrop. Phys. 26 (2006) 314. [6] M. Ageron, et al., Nucl. Instr. and Meth. A 578 (2007) 498. [7] Track Reconstruction and Point Source Searches with ANTARES, Aart Heijboer, Universiteit van Amsterdam, The Netherlands, 2004.