The calibration units of KM3NeT Le Breton, R.; Billault, M.; Boutonnet, C. ...
Journal of instrumentation,
09/2021, Letnik:
16, Številka:
9
Journal Article
Recenzirano
Odprti dostop
KM3NeT is a deep-sea infrastructure composed of two neutrino telescopes being deployed in the Mediterranean Sea: ARCA, near Sicily in Italy, designed for neutrino astronomy, and ORCA, near Toulon in ...France, designed for neutrino oscillation physics. To achieve the best performance, the exact location of the optical modules, affected by sea current, must be known at any time and the timing resolution between optical modules must reach the nanosecond. Moreover, the properties of the environment in which the telescopes are deployed must be continuously monitored because they affect the timing and positioning calibration. KM3NeT is going to deploy several dedicated Calibration Units to meet these calibration goals. Because of the difference in size between ARCA and ORCA, the design of the Calibration Unit is not the same for the two sites. This proceeding describes all the devices, features and purposes of the Calibration Units with a focus on the ORCA Calibration Unit.
Letter of intent for KM3NeT 2.0 Adrián-Martínez, S; Aharonian, F; Aiello, S ...
Journal of physics. G, Nuclear and particle physics,
08/2016, Letnik:
43, Številka:
8
Journal Article, Publication
Recenzirano
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The main objectives of the KM3NeT Collaboration are (i) the discovery and subsequent observation of high-energy neutrino sources in the Universe and (ii) the determination of the mass hierarchy of ...neutrinos. These objectives are strongly motivated by two recent important discoveries, namely: (1) the high-energy astrophysical neutrino signal reported by IceCube and (2) the sizable contribution of electron neutrinos to the third neutrino mass eigenstate as reported by Daya Bay, Reno and others. To meet these objectives, the KM3NeT Collaboration plans to build a new Research Infrastructure consisting of a network of deep-sea neutrino telescopes in the Mediterranean Sea. A phased and distributed implementation is pursued which maximises the access to regional funds, the availability of human resources and the synergistic opportunities for the Earth and sea sciences community. Three suitable deep-sea sites are selected, namely off-shore Toulon (France), Capo Passero (Sicily, Italy) and Pylos (Peloponnese, Greece). The infrastructure will consist of three so-called building blocks. A building block comprises 115 strings, each string comprises 18 optical modules and each optical module comprises 31 photo-multiplier tubes. Each building block thus constitutes a three-dimensional array of photo sensors that can be used to detect the Cherenkov light produced by relativistic particles emerging from neutrino interactions. Two building blocks will be sparsely configured to fully explore the IceCube signal with similar instrumented volume, different methodology, improved resolution and complementary field of view, including the galactic plane. One building block will be densely configured to precisely measure atmospheric neutrino oscillations.
ANTARES: The first undersea neutrino telescope Ageron, M.; Anghinolfi, M.; Ardid, M. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
11/2011, Letnik:
656, Številka:
1
Journal Article
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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.
Reconstruction in Cone-Beam Tomography can suffer from artifacts due to geometrical misalignments of the source-detector system. They can be avoided by a complete and precise description of the ...system. We present a high precision method for the geometric calibration for the PIXSCAN, a small animal X-ray CT scanner demonstrator based on hybrid pixel detectors (XPAD2). The specificities of the XPAD2 detectors (dead pixels, tilts and gaps between modules...) made the calibration of the PIXSCAN quite difficult. The method uses a calibration object consisting of a hollow cylinder of polycarbonate on which we positioned four metallic balls. It requires 360 X-ray images (1° increments). An analytic expression of the 3 image ellipses has been derived. It is used for a least square regression of the 13 alignment parameters after a correction of the internal XPAD2 geometry. Our method is fast and completely automated, achieving a precision of about 30 μm.
KM3NeT is a research infrastructure located in the Mediterranean Sea, that will consist of two deep-sea Cherenkov neutrino detectors. With one detector (ARCA), the KM3NeT Collaboration aims at ...identifying and studying TeV–PeV astrophysical neutrino sources. With the other detector (ORCA), the neutrino mass ordering will be determined by studying GeV-scale atmospheric neutrino oscillations. The first KM3NeT detection units were deployed at the Italian and French sites between 2015 and 2017. In this paper, a description of the detector is presented, together with a summary of the procedures used to calibrate the detector in-situ. Finally, the measurement of the atmospheric muon flux between 2232–3386 m seawater depth is obtained.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The ANTARES collaboration has performed a series of in-situ measurements to study the background light for a planned undersea neutrino telescope. Such background can be caused by
40
K
decays or by ...biological activity. We report on measurements at two sites in the Mediterranean Sea at depths of 2400 m and 2700 m, respectively. Three photomultiplier tubes were used to measure single counting rates and coincidence rates for pairs of tubes at various distances. The background rate is seen to consist of three components: a constant rate due to
40
K
decays, a continuum rate that varies on a time scale of several hours simultaneously over distances up to at least 40 m, and random bursts a few seconds long that are only correlated in time over distances of the order of a meter. A trigger requiring coincidences between nearby photomultiplier tubes should reduce the trigger rate for a neutrino telescope to a manageable level with only a small loss in efficiency.
A
bstract
In the era of precision measurements of the neutrino oscillation parameters, upcoming neutrino experiments will also be sensitive to physics beyond the Standard Model. KM3NeT/ORCA is a ...neutrino detector optimised for measuring atmospheric neutrinos from a few GeV to around 100 GeV. In this paper, the sensitivity of the KM3NeT/ORCA detector to neutrino decay has been explored. A three-flavour neutrino oscillation scenario, where the third neutrino mass state
ν
3
decays into an invisible state, e.g. a sterile neutrino, is considered. We find that KM3NeT/ORCA would be sensitive to invisible neutrino decays with 1
/α
3
=
τ
3
/m
3
<
180 ps
/
eV at 90% confidence level, assuming true normal ordering. Finally, the impact of neutrino decay on the precision of KM3NeT/ORCA measurements for
θ
23
,
Δ
m
31
2
and mass ordering have been studied. No significant effect of neutrino decay on the sensitivity to these measurements has been found.
A
bstract
Studying atmospheric neutrino oscillations in the few-GeV range with a multi-megaton detector promises to determine the neutrino mass hierarchy. This is the main science goal pursued by the ...future KM3NeT/ORCA water Cherenkov detector in the Mediterranean Sea. In this paper, the processes that limit the obtainable resolution in both energy and direction in charged-current neutrino events in the ORCA detector are investigated. These processes include the composition of the hadronic fragmentation products, the subsequent particle propagation and the photon-sampling fraction of the detector. GEANT simulations of neutrino interactions in seawater produced by GENIE are used to study the effects in the 1-20 GeV range. It is found that fluctuations in the hadronic cascade in conjunction with the variation of the inelasticity
y
are most detrimental to the resolutions. The effect of limited photon sampling in the detector is of significantly less importance. These results will therefore also be applicable to similar detectors/media, such as those in ice.
The prototype detection unit of the KM3NeT detector Adrián-Martínez, S.; Ageron, M.; Anghinolfi, M. ...
The European physical journal. C, Particles and fields,
02/2016, Letnik:
76, Številka:
2
Journal Article
Recenzirano
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A prototype detection unit of the KM3NeT deep-sea neutrino telescope has been installed at 3500m depth 80 km offshore the Italian coast. KM3NeT in its final configuration will contain several ...hundreds of detection units. Each detection unit is a mechanical structure anchored to the sea floor, held vertical by a submerged buoy and supporting optical modules for the detection of Cherenkov light emitted by charged secondary particles emerging from neutrino interactions. This prototype string implements three optical modules with 31 photomultiplier tubes each. These optical modules were developed by the KM3NeT Collaboration to enhance the detection capability of neutrino interactions. The prototype detection unit was operated since its deployment in May 2014 until its decommissioning in July 2015. Reconstruction of the particle trajectories from the data requires a nanosecond accuracy in the time calibration. A procedure for relative time calibration of the photomultiplier tubes contained in each optical module is described. This procedure is based on the measured coincidences produced in the sea by the
40
K background light and can easily be expanded to a detector with several thousands of optical modules. The time offsets between the different optical modules are obtained using LED nanobeacons mounted inside them. A set of data corresponding to 600 h of livetime was analysed. The results show good agreement with Monte Carlo simulations of the expected optical background and the signal from atmospheric muons. An almost background-free sample of muons was selected by filtering the time correlated signals on all the three optical modules. The zenith angle of the selected muons was reconstructed with a precision of about 3
∘
.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The first prototype of a photo-detection unit of the future KM3NeT neutrino telescope has been deployed in the deep waters of the Mediterranean Sea. This digital optical module has a novel design ...with a very large photocathode area segmented by the use of 31 three inch photomultiplier tubes. It has been integrated in the ANTARES detector for in-situ testing and validation. This paper reports on the first months of data taking and rate measurements. The analysis results highlight the capabilities of the new module design in terms of background suppression and signal recognition. The directionality of the optical module enables the recognition of multiple Cherenkov photons from the same
40
K decay and the localisation of bioluminescent activity in the neighbourhood. The single unit can cleanly identify atmospheric muons and provide sensitivity to the muon arrival directions.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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