| 1. |
- Ageron, M., et al.
(författare)
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Studies of a full-scale mechanical prototype line for the ANTARES neutrino telescope and tests of a prototype instrument for deep-sea acoustic measurements
- 2007
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier. - 0168-9002 .- 1872-9576. ; 581:3, s. 695-708
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Tidskriftsartikel (refereegranskat)abstract
- full-scale mechanical prototype line was deployed to a depth of 2500 m to test the leak tightness of the electronics containers and the pressure-resistant properties of an electromechanical cable under evaluation for use in the ANTARES deep-sea neutrino telescope. During a month-long immersion study, line parameter data were taken using miniature autonomous data loggers and shore-based optical time domain reflectometry. Details of the mechanical prototype line, the electromechanical cable and data acquisition are presented. Data taken during the immersion study revealed deficiencies in the pressure resistance of the electromechanical cable terminations at the entry points to the electronics containers. The improvements to the termination, which have been integrated into subsequent detection lines, are discussed. The line also allowed deep-sea acoustic measurements with a prototype hydrophone system. The technical setup of this system is described, and the first results of the data analysis are presented. (c) 2007 Elsevier B.V. All rights reserved.
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| 2. |
- Ageron, M., et al.
(författare)
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The ANTARES optical beacon system
- 2007
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier. - 0168-9002 .- 1872-9576. ; 578:3, s. 498-509
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Tidskriftsartikel (refereegranskat)abstract
- ANTARES is a neutrino telescope being deployed in the Mediterranean Sea. It consists of a three-dimensional array of photomultiplier tubes that can detect the Cherenkov light induced by charged particles produced in the interactions of neutrinos with the surrounding medium. High angular resolution can be achieved, in particular, when a muon is produced, provided that the Cherenkov photons are detected with sufficient timing precision. Considerations of the intrinsic time uncertainties stemming from the transit time spread in the photomultiplier tubes and the mechanism of transmission of light in sea water lead to the conclusion that a relative time accuracy of the order of 0.5 ns is desirable. Accordingly, different time calibration systems have been developed for the ANTARES telescope. In this article, a system based on Optical Beacons, a set of external and well-controlled pulsed light sources located throughout the detector, is described. This calibration system takes into account the optical properties of sea water, which is used as the detection volume of the ANTARES telescope. The design, tests, construction and first results of the two types of beacons, LED and laser-based, are presented. (C) 2007 Elsevier B.V. All rights reserved.
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| 3. |
- Aguilar, J. A., et al.
(författare)
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First results of the instrumentation line for the deep-sea ANTARES neutrino telescope
- 2006
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Ingår i: Astroparticle physics. - : Elsevier. - 0927-6505 .- 1873-2852. ; 26:4-5, s. 314-324
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Tidskriftsartikel (refereegranskat)abstract
- In 2005, the ANTARES Collaboration deployed and operated at a depth of 2500 m a so-called Mini Instrumentation Line equipped with Optical Modules (MILOM) at the ANTARES site. The various data acquired during the continuous operation from April to December 2005 of the MILOM confirm the satisfactory performance of the Optical Modules, their front-end electronics and readout system. as well as the calibration devices of the detector. The in situ measurement of the Optical Module time response yields a resolution better than 0.5 ns. The performance of the acoustic positioning system, which enables the spatial reconstruction of the ANTARES detector with a precision of about 10 cm, is verified. These results demonstrate that with the full ANTARES neutrino telescope the design angular resolution of better than 0.3 degrees can be realistically achieved.
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| 4. |
- Aguilar, J. A., et al.
(författare)
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The data acquisition system for the ANTARES neutrino telescope
- 2007
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier. - 0168-9002 .- 1872-9576. ; 570:1, s. 107-116
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Tidskriftsartikel (refereegranskat)abstract
- The ANTARES neutrino telescope is being constructed in the Mediterranean Sea. It consists of a large three-dimensional array of photo-multiplier tubes. The data acquisition system of the detector takes care of the digitisation of the photo-multiplier tube signals, data transport, data filtering, and data storage. The detector is operated using a control program interfaced with all elements. The design and the implementation of the data acquisition system are described. (c) 2006 Elsevier B.V. All rights reserved.
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| 5. |
- Ageron, M., et al.
(författare)
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ANTARES : The first undersea neutrino telescope
- 2011
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier. - 0168-9002 .- 1872-9576. ; 656:1, s. 11-38
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Tidskriftsartikel (refereegranskat)abstract
- The ANTARES Neutrino Telescope was completed in May 2008 and is the first operational Neutrino Telescope in the Mediterranean Sea. The main purpose of the detector is to perform neutrino astronomy and the apparatus also offers facilities for marine and Earth sciences. This paper describes the design, the construction and the installation of the telescope in the deep sea, offshore from Toulon in France. An illustration of the detector performance is given. (C) 2011 Elsevier B.V. All rights reserved.
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| 6. |
- Aguilar, J A, et al.
(författare)
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Transmission of light in deep sea water at the site of the ANTARES neutrino telescope
- 2005
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Ingår i: Astroparticle physics. - : Elsevier. - 0927-6505 .- 1873-2852. ; 23:1, s. 131-155
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Tidskriftsartikel (refereegranskat)abstract
- The ANTARES neutrino telescope is a large photomultiplier array designed to detect neutrino-induced upward-going muons by their Cherenkov radiation. Understanding the absorption and scattering of light in the deep Mediterranean is fundamental to optimising the design and performance of the detector. This paper presents measurements of blue and UV light transmission at the ANTARES site taken between 1997 and 2000. The derived values for the scattering length and the angular distribution of particulate scattering were found to be highly correlated, and results are therefore presented in terms of an absorption length;,ab, and an effective scattering length lambda(sct)(eff). The values for blue (UV) light are found to be lambda(abs) similar or equal to 60(26) m, lambda(sct)(eff similar or equal to) 265(122) m, with significant (similar to15%) time variability. Finally, the results of ANTARES simulations showing the effect of these water properties on the anticipated performance of the detector are presented. (C) 2004 Elsevier B.V. All rights reserved.
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| 7. |
- Aguilar, J A, et al.
(författare)
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Study of large hemispherical photomultiplier tubes for the ANTARES neutrino telescope
- 2005
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier. - 0168-9002 .- 1872-9576. ; 555:1-2, s. 132-141
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Tidskriftsartikel (refereegranskat)abstract
- The ANTARES neutrino telescope, to be immersed depth in the Mediterranean Sea, will consist of a three-dimensional matrix of 900 large area photomultiplier tubes housed in pressure-resistant glass spheres. The selection of the optimal photomultiplier was a critical step for the project and required an intensive phase of tests and developments carried out in close collaboration with the main manufacturers worldwide. This paper provides an overview of the tests performed by the collaboration and describes in detail the features of the photomultiplier tube chosen for ANTARES. (c) 2005 Elsevier B.V. All rights reserved.
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| 8. |
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| 9. |
- Betoule, M., et al.
(författare)
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Improved cosmological constraints from a joint analysis of the SDSS-II and SNLS supernova samples
- 2014
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 568, s. A22-
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Tidskriftsartikel (refereegranskat)abstract
- Aims. We present cosmological constraints from a joint analysis of type la supernova (SN Ia) observations obtained by the SDSS-II and SNLS collaborations. The dataset includes several low-redshift samples (z < 0.1), all three seasons from the SDSS-11 (0.05 < z < 0.4), and three years from SNLS (0.2 < z < 1), and it totals 740 spectroscopically confirmed type la supernovae with high quality light curves. Methods. We followed the methods and assumptions of the SNLS three-year data analysis except for the following important improvements: I) the addition of the full SDSS-II spectroscopically-confirmed SN la sample in both the training of the SALT2 light-curve model and in the Hubble diagram analysis (374 SNe); 2) intercalibration of the SNLS and SDSS surveys and reduced systematic uncertainties in the photometric calibration, performed blindly with respect to the cosmology analysis; and 3) a thorough investigation of systematic errors associated with the SALT2 modeling of SN la light curves. Results. We produce recalibrated SN la light curves and associated distances for the SDSS-II and SNLS samples. The large SOSS-II sample provides an effective, independent, low -z anchor for the Hubble diagram and reduces the systematic error from calibration systematics in the low -z SN sample. For a flat ACDM cosmology, we find Omega(m), = 0.295 0.034 (stat+sys), a value consistent with the most recent cosmic microwave background (CMB) measurement from the Planck and WMAP experiments. Our result is 1.8 sigma (stat+sys) different than the previously published result of SNLS three-year data. The change is due primarily to improvements in the SNLS photometric calibration. When combined with CMB constraints, we measure a constant dark energy equation of state parameter omega = -1.018 +/- 0,057 (sral+sys) for a fiat universe. Adding baryon acoustic oscillation distance measurements gives similar constraints: omega = 59 -1.027 0.055. Our supernova measurements provide the most stringent constraints to date on the nature of dark energy.
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| 10. |
- Balland, C., et al.
(författare)
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The ESO/VLT 3rd year Type Ia supernova data set from the supernova legacy survey
- 2009
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 507:1, s. 85-103
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Tidskriftsartikel (refereegranskat)abstract
- Aims. We present 139 spectra of 124 Type Ia supernovae (SNe Ia) that were observed at the ESO/VLT during the first three years of the Canada-France-Hawa Telescope (CFHT) supernova legacy survey (SNLS). This homogeneous data set is used to test for redshift evolution of SN Ia spectra, and will be used in the SNLS 3rd year cosmological analyses. Methods. Spectra have been reduced and extracted with a dedicated pipeline that uses photometric information from deep CFHT legacy survey (CFHT-LS) reference images to trace, at sub-pixel accuracy, the position of the supernova on the spectrogram as a function of wavelength. It also separates the supernova and its host light in similar to 60% of cases. The identification of the supernova candidates is performed using a spectrophotometric SN Ia model. Results. A total of 124 SNe Ia, roughly 50% of the overall SNLS spectroscopic sample, have been identified using the ESO/VLT during the first three years of the survey. Their redshifts range from z = 0.149 to z = 1.031. The average redshift of the sample is z = 0.63 +/- 0.02. This constitutes the largest SN Ia spectral set to date in this redshift range. The spectra are presented along with their best-fit spectral SN Ia model and a host model where relevant. In the latter case, a host subtracted spectrum is also presented. We produce average spectra for pre-maximum, maximum and post-maximum epochs for both z < 0.5 and z >= 0.5 SNe Ia. We find that z < 0.5 spectra have deeper intermediate mass element absorptions than z = 0.5 spectra. The differences with redshift are consistent with the selection of brighter and bluer supernovae at higher redshift.
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