-
S. Adrián-Martínez,
M. Ageron,
J.A. Aguilar,
F. Aharonian,
S. Aiello,
A. Albert,
M. Alexandri,
F. Ameli,
E.G. Anassontzis,
M. Anghinolfi, [......],
P. Werneke,
R.J. White,
G. Wijnker,
J. Wilms,
E. de Wolf,
H. Yepes,
V. Zhukov,
E. Zonca,
J.D. Zornoza,
J. Zúñiga
[show abstract]
[hide abstract]
ABSTRACT: Detection of high-energy neutrinos from distant astrophysical sources will open a new window on the Universe. The detection principle exploits the measurement of Cherenkov light emitted by charged particles resulting from neutrino interactions in the matter containing the telescope. A novel multi-PMT digital optical module (DOM) was developed to contain 31 3-inch photomultiplier tubes (PMTs). In order to maximize the detector sensitivity, each PMT will be surrounded by an expansion cone which collects photons that would otherwise miss the
photocathode. Results for various angles of incidence with respect to the PMT surface indicate an increase in collection efficiency by 30% on average for angles up to 45°� with respect to the perpendicular. Ray-tracing calculations could reproduce the measurements, allowing to estimate an increase in the overall photocathode sensitivity, integrated over all angles of incidence, by 27% (for a single PMT). Prototype DOMs, being built by the KM3NeT consortium, will be equipped with these expansion cones.
Journal of Instrumentation 03/2013; 8(T03006). · 1.87 Impact Factor
-
S. Adrián-Martínez,
I. Al Samarai,
A. Albert,
M. André,
M. Anghinolfi,
G. Anton,
S. Anvar,
M. Ardid,
A. C. Assis Jesus,
T. Astraatmadja, [......],
P. Vernin,
E. Visser,
S. Wagner,
G. Wijnker,
J. Wilms,
E. de Wolf,
H. Yepes,
D. Zaborov,
J. D. Zornoza,
J. Zúniga
[show abstract]
[hide abstract]
ABSTRACT: A search for neutrino-induced muons in correlation with a selection of 40
gamma-ray bursts that occurred in 2007 has been performed with the ANTARES
neutrino telescope. During that period, the detector consisted of 5 detection
lines. The ANTARES neutrino telescope is sensitive to TeV--PeV neutrinos that
are predicted from gamma-ray bursts. No events were found in correlation with
the prompt photon emission of the gamma-ray bursts and upper limits have been
placed on the flux and fluence of neutrinos for different models.
02/2013;
-
ANTARES Collaboration,
S. Adrián-Martinez,
I. Al Samarai,
A. Albert,
M. André,
M. Anghinolfi,
G. Anton,
L. Anton,
S. Anvar,
M. Ardid, [......],
E. Visser,
S. Wagner,
G. Wijnker,
J. Wilms,
E. de Wolf,
K. Yatkin,
H. Yepes,
D. Zaborov,
J. D. Zornoza,
J. Zúñiga
[show abstract]
[hide abstract]
ABSTRACT: A search for high-energy neutrinos coming from the direction of the Sun has
been performed using the data recorded by the ANTARES neutrino telescope during
2007 and 2008. The neutrino selection criteria have been chosen to maximize the
selection of possible signals produced by the self-annihilation of weakly
interacting massive particles accumulated in the centre of the Sun with respect
to the atmospheric background. After data unblinding, the number of neutrinos
observed towards the Sun was found to be compatible with background
expectations. The 90\% CL upper limits in terms of spin-dependent and
spin-independent WIMP-proton cross-sections are derived and compared to
predictions of two supersymmetric models, CMSSM and MSSM-7. The ANTARES limits
are competitive with those obtained by other neutrino observatories and are
more stringent than those obtained by direct search experiments for the
spin-dependent WIMP-proton cross-section.
02/2013;
-
R. Bates,
M. Battistin,
S. Berry,
J. Berthoud,
A. Bitadze,
P. Bonneau,
J. Botelho-Direito,
N. Bousson,
G. Boyd,
G. Bozza, [......],
D. Lombard,
M. Mathieu,
S. McMahon,
K. Nagai,
E. Perez-Rodriguez,
C. Rossi,
A. Rozanov,
V. Vacek,
M. Vitek,
L. Zwalinski
[show abstract]
[hide abstract]
ABSTRACT: Precision sound velocity measurements can simultaneously determine binary gas
composition and flow. We have developed an analyzer with custom electronics,
currently in use in the ATLAS inner detector, with numerous potential
applications. The instrument has demonstrated ~0.3% mixture precision for
C3F8/C2F6 mixtures and < 10-4 resolution for N2/C3F8 mixtures. Moderate and
high flow versions of the instrument have demonstrated flow resolutions of +/-
2% F.S. for flows up to 250 l.min-1, and +/- 1.9% F.S. for linear flow
velocities up to 15 ms-1; the latter flow approaching that expected in the
vapour return of the thermosiphon fluorocarbon coolant recirculator being built
for the ATLAS silicon tracker.
10/2012;
-
R. Bates,
M. Battistin,
S. Berry,
J. Berthoud,
A. Bitadze,
P. Bonneau,
J. Botelho-Direito,
N. Bousson,
G. Boyd,
G. Bozza, [......],
D. Lombard,
M. Mathieu,
S. McMahon,
K. Nagai,
E. Perez-Rodriguez,
C. Rossi,
A. Rozanov,
V. Vacek,
M. Vitek,
L. Zwalinski
[show abstract]
[hide abstract]
ABSTRACT: An upgrade to the ATLAS silicon tracker cooling control system may require a
change from C3F8 (octafluoro-propane) evaporative coolant to a blend containing
10-25% of C2F6 (hexafluoro-ethane). Such a change will reduce the evaporation
temperature to assure thermal stability following radiation damage accumulated
at full LHC luminosity. Central to this upgrade is a new ultrasonic instrument
in which sound transit times are continuously measured in opposite directions
in flowing gas at known temperature and pressure to deduce the C3F8/C2F6 flow
rate and mixture composition. The instrument and its Supervisory, Control and
Data Acquisition (SCADA) software are described in this paper. Several
geometries for the instrument are in use or under evaluation. An instrument
with a pinched axial geometry intended for analysis and measurement of moderate
flow rates has demonstrated a mixture resolution of 3.10-3 for C3F8/C2F6 molar
mixtures with 20%C2F6, and a flow resolution of 2% of full scale for mass flows
up to 30gs-1. In mixtures of widely-differing molecular weight (mw), higher
mixture precision is possible: a sensitivity of <5.10-5 to leaks of C3F8 into
part of the ATLAS tracker nitrogen envelope (mw difference 160) has been seen.
An instrument with an angled sound path geometry has been developed for use at
high fluorocarbon mass flow rates of around 1.2 kgs-1 - corresponding to full
flow in a new 60kW thermosiphon recirculator under construction for the ATLAS
silicon tracker. Extensive computational fluid dynamics studies were performed
to determine the preferred geometry (ultrasonic transducer spacing and
placement, together with the sound crossing angle with respect to the vapour
flow direction). A prototype with 45deg crossing angle has demonstrated a flow
resolution of 1.9% of full scale for linear flow velocities up to 15 ms-1. The
instrument has many potential applications.
10/2012;
-
ANTARES Collaboration,
S. Adrián-Martínez,
I. Al Samarai,
A. Albert,
M. André,
M. Anghinolfi,
G. Anton,
S. Anvar,
M. Ardid,
T. Astraatmadja, [......],
P. Vernin,
E. Visser,
S. Wagner,
G. Wijnker,
J. Wilms,
E. de Wolf,
H. Yepes,
D. Zaborov,
J. D. Zornoza,
J. Zúñiga
[show abstract]
[hide abstract]
ABSTRACT: In this paper, a time integrated search for point sources of cosmic neutrinos
is presented using the data collected from 2007 to 2010 by the ANTARES neutrino
telescope. No statistically significant signal has been found and upper limits
on the neutrino flux have been obtained. Assuming an $E_{\nu}^{-2}$ spectrum,
these flux limits are at $1-10\times10^{-8}$ GeV cm$^{-2}$ s$^{-1}$ for
declinations ranging from $-90^{\circ}$ to 40$^{\circ}$. Limits for specific
models of RX J1713.7-3946 and Vela X, which include information on the source
morphology and spectrum, are also given.
07/2012;
-
ANTARES collaboration,
S. Adrian-Martinez,
I. Al Samarai,
A. Albert,
M. Andre,
M. Anghinolfi,
G. Anton,
S. Anvar,
M. Ardid,
T. Astraatmadja, [......],
P. Vernin,
E. Visser,
S. Wagner,
G. Wijnker,
J. Wilms,
E. de Wolf,
H. Yepes,
D. Zaborov,
J. D. Zornoza,
J. Zuniga
[show abstract]
[hide abstract]
ABSTRACT: The data taken with the ANTARES neutrino telescope from 2007 to 2010, a total
live time of 863 days, are used to measure the oscillation parameters of
atmospheric neutrinos. Muon tracks are reconstructed with energies as low as 20
GeV. Neutrino oscillations will cause a suppression of vertical upgoing muon
neutrinos of such energies crossing the Earth. The parameters determining the
oscillation of atmospheric neutrinos are extracted by fitting the event rate as
a function of the ratio of the estimated neutrino energy and reconstructed
flight path through the Earth. Measurement contours of the oscillation
parameters in a two-flavour approximation are derived. Assuming maximum mixing,
a mass difference of $\Delta m_{32}^2=(3.1\pm 0.9)\cdot 10^{-3}$ eV$^2$ is
obtained, in good agreement with the world average value.
06/2012;
-
The ANTARES Collaboration,
the LIGO Scientific Collaboration,
the Virgo Collaboration,
S. Adrián-Martínez,
I. Al Samarai,
A. Albert,
M. André,
M. Anghinolfi,
G. Anton,
S. Anvar, [......],
M. Yvert,
A. Zadroźny,
M. Zanolin,
J. -P. Zendri,
F. Zhang,
L. Zhang,
C. Zhao,
N. Zotov,
M. E. Zucker,
J. Zweizig
[show abstract]
[hide abstract]
ABSTRACT: We present the results of the first search for gravitational wave bursts
associated with high energy neutrinos. Together, these messengers could reveal
new, hidden sources that are not observed by conventional photon astronomy,
particularly at high energy. Our search uses neutrinos detected by the
underwater neutrino telescope ANTARES in its 5 line configuration during the
period January - September 2007, which coincided with the fifth and first
science runs of LIGO and Virgo, respectively. The LIGO-Virgo data were analysed
for candidate gravitational-wave signals coincident in time and direction with
the neutrino events. No significant coincident events were observed. We place
limits on the density of joint high energy neutrino - gravitational wave
emission events in the local universe, and compare them with densities of
merger and core-collapse events.
05/2012;
-
J.A. Aguilar,
I. Al Samarai,
A. Albert,
M. André,
M. Anghinolfi,
G. Anton,
S. Anvar,
M. Ardid,
A.C. Assis Jesus,
T. Astraatmadja, [......],
G. Vannoni,
M. Vecchi,
P. Vernin,
G. Wijnker,
J. Wilms,
E. de Wolf,
H. Yepes,
D. Zaborov,
J.D. Zornoza,
J. Zúñiga
Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment 05/2012; · 1.21 Impact Factor
-
S. Adrián-Martínez,
I. Al Samarai,
A. Albert,
M. André,
M. Anghinolfi,
G. Anton,
S. Anvar,
M. Ardid,
A.C. Assis Jesus,
T. Astraatmadja, [......],
M. Vecchi,
P. Vernin,
S. Wagner,
G. Wijnker,
J. Wilms,
E. de Wolf,
H. Yepes,
D. Zaborov,
J.D. Zornoza,
J. Zúñiga
Astroparticle Physics 04/2012; · 3.22 Impact Factor
-
M. Ageron,
J.A. Aguilar,
I. Al Samarai,
A. Albert,
M. André,
M. Anghinolfi,
G. Anton,
S. Anvar,
M. Ardid,
A.C. Assis Jesus, [......],
G. Vannoni,
M. Vecchi,
P. Vernin,
G. Wijnker,
J. Wilms,
E. de Wolf,
H. Yepes,
D. Zaborov,
J.D. Zornoza,
J. Zúñiga
Astroparticle Physics 03/2012; · 3.22 Impact Factor
-
S. Adrián-Martínez,
M. Ageron,
J. A. Aguilar,
I. Al Samarai,
A. Albert,
M. André,
M. Anghinolfi,
G. Anton,
S. Anvar,
M. Ardid, [......],
M. Vecchi,
P. Vernin,
S. Wagner,
G. Wijnker,
J. Wilms,
E. de Wolf,
H. Yepes,
D. Zaborov,
J. D. Zornoza,
J. Zúñiga
[show abstract]
[hide abstract]
ABSTRACT: The ANTARES neutrino telescope, located 40km off the coast of Toulon in the
Mediterranean Sea at a mooring depth of about 2475m, consists of twelve
detection lines equipped typically with 25 storeys. Every storey carries three
optical modules that detect Cherenkov light induced by charged secondary
particles (typically muons) coming from neutrino interactions. As these lines
are flexible structures fixed to the sea bed and held taut by a buoy, sea
currents cause the lines to move and the storeys to rotate. The knowledge of
the position of the optical modules with a precision better than 10cm is
essential for a good reconstruction of particle tracks. In this paper the
ANTARES positioning system is described. It consists of an acoustic positioning
system, for distance triangulation, and a compass-tiltmeter system, for the
measurement of the orientation and inclination of the storeys. Necessary
corrections are discussed and the results of the detector alignment procedure
are described.
02/2012;
-
S. Adrián-Martínez,
J.A. Aguilar,
I. Al Samarai,
A. Albert,
M. André,
M. Anghinolfi,
G. Anton,
S. Anvar,
M. Ardid,
A.C. Assis Jesus, [......],
M. Vecchi,
P. Vernin,
S. Wagner,
G. Wijnker,
J. Wilms,
E. de Wolf,
H. Yepes,
D. Zaborov,
J.D. Zornoza,
J. Zúñiga
Astroparticle Physics 02/2012; · 3.22 Impact Factor
-
A. Bitadze,
R. Bates,
M. Battistin,
S. Berry,
P. Bonneau,
J. Botelho-Direito,
B. DiGirolamo,
J. Godlewski,
E. Perez-Rodriguez,
L. Zwalinski, [......],
M. Mathieu,
A. Rozanov,
G. Boyd,
M. Doubek,
V. Vacek,
M. Vitek,
K. Egorov,
S. Katunin,
S. McMahon,
K. Nagai
[show abstract]
[hide abstract]
ABSTRACT: An upgrade to the ATLAS silicon tracker cooling control system may require a
change from C3F8 (octafluoro-propane) to a blend containing 10-30% of C2F6
(hexafluoro-ethane) to reduce the evaporation temperature and better protect
the silicon from cumulative radiation damage with increasing LHC luminosity.
Central to this upgrade is a new acoustic instrument for the real-time
measurement of the C3F8/C2F6 mixture ratio and flow. The instrument and its
Supervisory, Control and Data Acquisition (SCADA) software are described in
this paper. The instrument has demonstrated a resolution of 3.10-3 for
C3F8/C2F6 mixtures with ~20%C2F6, and flow resolution of 2% of full scale for
mass flows up to 30gs-1. In mixtures of widely-differing molecular weight (mw),
higher mixture precision is possible: a sensitivity of < 5.10-4 to leaks of
C3F8 into the ATLAS pixel detector nitrogen envelope (mw difference 160) has
been seen. The instrument has many potential applications, including the
analysis of mixtures of hydrocarbons, vapours for semi-conductor manufacture
and anaesthesia.
01/2012;
-
S. Adrián-Martínez,
J. A. Aguilar,
I. Al Samarai,
A Albert,
M André,
M Anghinolfi,
G. Anton,
S. Anvar,
M. Ardid,
A. C. Assis Jesus, [......],
M. Vecchi,
P. Vernin,
S Wagner,
G. Wijnker,
J. Wilms,
E de Wolf,
H. Yepes,
D. Zaborov,
J. D. Zornoza,
J Zúñiga
[show abstract]
[hide abstract]
ABSTRACT: The ANTARES detector, completed in 2008, is the largest neutrino telescope in
the Northern hemisphere. It is located at a depth of 2.5 km in the
Mediterranean Sea, 40 km off the Toulon shore. The scientific scope of the
experiment is very broad, being the search for astrophysical neutrinos the main
goal. In this paper we collect the 22 contributions of the ANTARES
collaboration to the 32nd International Cosmic Ray Conference (ICRC 2011). At
this stage of the experiment the scientific output is very rich and the
contributions included in these proceedings cover the main physics results
(steady point sources, correlations with GRBs, diffuse fluxes, target of
opportunity programs, dark matter, exotic physics, oscillations, etc.) and some
relevant detector studies (water optical properties, energy reconstruction,
moon shadow, accoustic detection, etc.)
12/2011;
-
H. van Haren,
I. Taupier-Letage,
J. A. Aguilar,
A Albert,
M Anghinolfi,
G. Anton,
S. Anvar,
M. Ardid,
A. C. Assis Jesus,
T. Astraatmadja, [......],
B Vallage,
V. Van Elewyck,
M. Vecchi,
P. Vernin,
G. Wijnker,
E de Wolf,
H. Yepes,
D. Zaborov,
J. D. Zornoza,
J Zúñiga
[show abstract]
[hide abstract]
ABSTRACT: 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'.
11/2011;
-
S. Adrián-Martínez,
I. Al Samarai,
A Albert,
M André,
M Anghinolfi,
G. Anton,
S. Anvar,
M. Ardid,
T. Astraatmadja,
J J Aubert, [......],
P. Vernin,
E. Visser,
S Wagner,
G. Wijnker,
J. Wilms,
E de Wolf,
H. Yepes,
D. Zaborov,
J. D. Zornoza,
J Zúñiga
[show abstract]
[hide abstract]
ABSTRACT: The ANTARES telescope is well-suited to detect neutrinos produced in
astrophysical transient sources as it can observe a full hemisphere of the sky
at all times with a high duty cycle. Radio-loud active galactic nuclei with
jets pointing almost directly towards the observer, the so-called blazars, are
particularly attractive potential neutrino point sources. The all-sky monitor
LAT on board the Fermi satellite probes the variability of any given gamma-ray
bright blazar in the sky on time scales of hours to months. Assuming hadronic
models, a strong correlation between the gamma-ray and the neutrino fluxes is
expected. Selecting a narrow time window on the assumed neutrino production
period can significantly reduce the background.
An unbinned method based on the minimization of a likelihood ratio was
applied to a subsample of data collected in 2008 (61 days live time). By
searching for neutrinos during the high state periods of the AGN light curve,
the sensitivity to these sources was improved by about a factor of two with
respect to a standard time-integrated point source search. First results on the
search for neutrinos associated with ten bright and variable Fermi sources are
presented.
11/2011;
-
O. Kalekin,
J. Steijger,
H.Z. Peek,
S. Adrián-Martínez,
M. Ageron,
J.A. Aguilar,
F. Aharonian,
S. Aiello,
A. Albert,
M. Alexandri, [......],
P. Werneke,
R.J. White,
G. Wijnker,
J. Wilms,
E. de Wolf,
H. Yepes,
V. Zhukov,
E. Zonca,
J.D. Zornoza,
J. Zúñiga
[show abstract]
[hide abstract]
ABSTRACT: The KM3NeT project aims to construct a multi-cubic-kilometre scale neutrino telescope in the Mediterranean Sea. The telescope’s detection units, deployed in the deep sea, will be instrumented with optical modules, each housing 31 three-in. photomultiplier tubes (PMTs). Three companies are developing new types of 3in. PMTs for the KM3NeT project. The first PMT samples of type R6233 mod. have been delivered from Hamamatsu and tested at the Erlangen Centre for Astroparticle Physics and at Nikhef. The results of these tests are presented. Many of the parameters of the existing versions of these PMTs already meet the KM3NeT requirements and production versions will be used to build the first developmental optical modules. Hamamatsu have started the development of new versions of PMTs of current interest, with better timing parameters and as lightly larger photocathode. The first two examples of a new PMT from ET Enterprises are under tests at Nikhef. The delivery of first 82 mm diameter PMTs from MELZ is also expected in October 2011. To increase photodetection efficiency in the multi-PMT optical module, PMTs will be surrounded by reflective light gathering rings (‘expansion cones’). Test results of such an assembly are also presented.
Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment 11/2011; 695(2012):313-316. · 1.21 Impact Factor
-
S. Adrián-Martínez,
I. Al Samarai,
A. Albert,
M. André,
M. Anghinolfi,
G. Anton,
S. Anvar,
M. Ardid,
A. C. Assis Jesus,
T. Astraatmadja, [......],
M. Vecchi,
P. Vernin,
S. Wagner,
G. Wijnker,
J. Wilms,
E. de Wolf,
H. Yepes,
D. Zaborov,
J. D. Zornoza,
J. Zúñiga
[show abstract]
[hide abstract]
ABSTRACT: The group velocity of light has been measured at eight different wavelengths
between 385 nm and 532 nm in the Mediterranean Sea at a depth of about 2.2 km
with the ANTARES optical beacon systems. A parametrisation of the dependence of
the refractive index on wavelength based on the salinity, pressure and
temperature of the sea water at the ANTARES site is in good agreement with
these measurements.
10/2011;
-
ANTARES Collaboration,
S. Adrián-Martínez,
J. A. Aguilar,
I. Al Samarai,
A. Albert,
M. André,
M. Anghinolfi,
G. Anton,
S. Anvar,
M. Ardid, [......],
M. Vecchi,
P. Vernin,
S. Wagner,
G. Wijnker,
J. Wilms,
E. de Wolf,
H. Yepes,
D. Zaborov,
J. D. Zornoza,
J. Zúñiga
[show abstract]
[hide abstract]
ABSTRACT: Magnetic monopoles are predicted in various unified gauge models and could be
produced at intermediate mass scales. Their detection in a neutrino telescope
is facilitated by the large amount of light emitted compared to that from
muons. This paper reports on a search for upgoing relativistic magnetic
monopoles with the ANTARES neutrino telescope using a data set of 116 days of
live time taken from December 2007 to December 2008. The one observed event is
consistent with the expected atmospheric neutrino and muon background, leading
to a 90% C.L. upper limit on the monopole flux between 1.3E-17 and 8.9E-17
cm-2.s-1.sr-1 for monopoles with velocity beta greater than 0.625.
10/2011;
