62 research outputs found
Individual GRB sensitivity of a cubic-kilometer deep-sea neutrino telescope KM3NeT
Gamma-ray bursts (GRB) are powerful and highly variable sources of gamma rays
that indicate the existence of cosmic particle accelerators. Under the
assumption of hadronic acceleration in the jet, the expected neutrino energy
spectrum is derived according to the intrinsic fireball model parameters and to
the observed electromagnetic data of GRBs measured with ground-based and
satellite observations. Using the performance characteristics of a
cubic-kilometre scale neutrino detector placed in the Mediterranean Sea, the
number of events is calculated individually for all the GRBs having a known
redshift below the horizon of this detector. The good angular resolution of
this detector and the narrow time windows around the GRB detection time allow
suppression of almost all the atmospheric neutrino background. From the SWIFT
GRB catalogue, we have derived the mean characteristics of a burst in order to
be detected as an individual point source by a cubic-kilometre detector.Comment: 4 pages proceeding for the Very Large Volume Neutrino Telescopes
VLVNT 0
Integration of a Relational Database in the CERN PS Control System
The control system for the CERN 26 GEV Proton Synchrotron and its injectors is a generic system which can be adapted to other accelerators. Most configuration data are in a relational database. From these data we can generate object interfaces for equipment, configuration files for front-end computers, a read-only database for accelerator control interfacing, and full dynamic documentation on the Web. The database is also used in real time for runtime references and archives, and for the working data of several programs
Model based, detailed fault analysis in the CERN PS complex equipment
In the CERN PS Complex of accelerators, about a thousand of equipment of various type (power converters, RF cavities, beam measurement devices, vacuum systems etc...) are controlled using the so-called Control Protocol, already described in previous Conferences. This Protocol, a model based equipment access standard, provides, amongst other facilities, a uniform and structured fault description and report feature. The faults are organized in categories, following their gravity, and are presented at two levels: the first level is global and identical for all devices, the second level is very detailed and adapted to the peculiarities of each single device. All the relevant information is provided by the equipment specialists and is appropriately stored in static and real time data bases; in this way a unique set of data driven application programs can always cope with existing and newly added equipment. Two classes of applications have been implemented, the first one is intended for control room alarm purposes, and the second one is oriented for specialists diagnostics. The system is completed by a fault history report facility permitting easy retrieval of faults previously occurred, for example during the night
Performance of the First ANTARES Detector Line
In this paper we report on the data recorded with the first Antares detector
line. The line was deployed on the 14th of February 2006 and was connected to
the readout two weeks later. Environmental data for one and a half years of
running are shown. Measurements of atmospheric muons from data taken from
selected runs during the first six months of operation are presented.
Performance figures in terms of time residuals and angular resolution are
given. Finally the angular distribution of atmospheric muons is presented and
from this the depth profile of the muon intensity is derived.Comment: 14 pages, 9 figure
Acoustic and optical variations during rapid downward motion episodes in the deep north-western Mediterranean Sea
An Acoustic Doppler Current Profiler (ADCP) was moored at the deep-sea site
of the ANTARES neutrino telescope near Toulon, France, thus providing a unique
opportunity to compare high-resolution acoustic and optical observations
between 70 and 170 m above the sea bed at 2475 m. The ADCP measured downward
vertical currents of magnitudes up to 0.03 m s-1 in late winter and early
spring 2006. In the same period, observations were made of enhanced levels of
acoustic reflection, interpreted as suspended particles including zooplankton,
by a factor of about 10 and of horizontal currents reaching 0.35 m s-1. These
observations coincided with high light levels detected by the telescope,
interpreted as increased bioluminescence. During winter 2006 deep dense-water
formation occurred in the Ligurian subbasin, thus providing a possible
explanation for these observations. However, the 10-20 days quasi-periodic
episodes of high levels of acoustic reflection, light and large vertical
currents continuing into the summer are not direct evidence of this process. It
is hypothesized that the main process allowing for suspended material to be
moved vertically later in the year is local advection, linked with topographic
boundary current instabilities along the rim of the 'Northern Current'.Comment: 30 pages, 7 figure
The ANTARES Optical Beacon System
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.Comment: 21 pages, 18 figures, submitted to Nucl. Instr. and Meth. Phys. Res.
Performance of the front-end electronics of the ANTARES neutrino telescope
ANTARES is a high-energy neutrino telescope installed in the Mediterranean
Sea at a depth of 2475 m. It consists of a three-dimensional array of optical
modules, each containing a large photomultiplier tube. A total of 2700
front-end ASICs named Analogue Ring Samplers (ARS) process the phototube
signals, measure their arrival time, amplitude and shape as well as perform
monitoring and calibration tasks. The ARS chip processes the analogue signals
from the optical modules and converts information into digital data. All the
information is transmitted to shore through further multiplexing electronics
and an optical link. This paper describes the performance of the ARS chip;
results from the functionality and characterization tests in the laboratory are
summarized and the long-term performance in the apparatus is illustrated.Comment: 20 pages, 22 figures, published in Nuclear Instruments and Methods
ANTARES: the first undersea neutrino telescope
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
Etude des Sursauts Gamma à partir des neutrinos de haute-énergie avec le telescope ANTARES Analyse du positionnement acoustique du détecteur
Le télescope ANTARES, déployé en mer Méditerranée à 2500 m de profondeur, est destiné à la détection de neutrinos cosmiques de haute-énergie. Le positionnement du détecteur est assuré par un système acoustique qui permet d'atteindre une précision de quelques centimètres par triangulation des distances caractéristiques des couples de modules acoustiques. Parmi les sources astrophysiques recherchées figurent les sursauts Gamma, phénomènes cataclysmiques signant la formation d'un trou noir, suscepyibles d'émettre des neutrinos détectables par ANTARES. Le développement d'une méthode d'analyse dédiée à ce type de signal est étudié dans ce travail dans un but de recherche de corrélation entre émissions gamma (détectées par des satellites) et neutrinos issus des sursauts Gamm
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