0000000000050486
AUTHOR
C. Colnard
The data acquisition system for the ANTARES neutrino telescope
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.
The design and performance of IceCube DeepCore
The IceCube neutrino observatory in operation at the South Pole, Antarctica, comprises three distinct components: a large buried array for ultrahigh energy neutrino detection, a surface air shower array, and a new buried component called DeepCore. DeepCore was designed to lower the IceCube neutrino energy threshold by over an order of magnitude, to energies as low as about 10 GeV. DeepCore is situated primarily 2100 m below the surface of the icecap at the South Pole, at the bottom center of the existing IceCube array, and began taking physics data in May 2010. Its location takes advantage of the exceptionally clear ice at those depths and allows it to use the surrounding IceCube detector a…
First search for extremely high energy cosmogenic neutrinos with the IceCube Neutrino Observatory.
We report on the results of the search for extremely-high energy (EHE) neutrinos with energies above $10^7$ GeV obtained with the partially ($\sim$30%) constructed IceCube in 2007. From the absence of signal events in the sample of 242.1 days of effective livetime, we derive a 90% C.L. model independent differential upper limit based on the number of signal events per energy decade at $E^2 \phi_{\nu_e+\nu_\mu+\nu_\tau}\simeq 1.4 \times 10^{-6}$ GeV cm$^{-2}$ sec$^{-1}$ sr$^{-1}$ for neutrinos in the energy range from $3\times10^7$ to $3\times10^9$ GeV.
The energy spectrum of atmospheric neutrinos between 2 and 200 TeV with the AMANDA-II detector
The muon and anti-muon neutrino energy spectrum is determined from 2000-2003 AMANDA telescope data using regularised unfolding. This is the first measurement of atmospheric neutrinos in the energy range 2 - 200 TeV. The result is compared to different atmospheric neutrino models and it is compatible with the atmospheric neutrinos from pion and kaon decays. No significant contribution from charm hadron decays or extraterrestrial neutrinos is detected. The capabilities to improve the measurement of the neutrino spectrum with the successor experiment IceCube are discussed.
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 desirabl…
First results of the Instrumentation Line for the deep-sea ANTARES neutrino telescope
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. T…
Measurement of acoustic attenuation in South Pole ice
Using the South Pole Acoustic Test Setup (SPATS) and a retrievable transmitter deployed in holes drilled for the IceCube experiment, we have measured the attenuation of acoustic signals by South Pole ice at depths between 190 m and 500 m. Three data sets, using different acoustic sources, have been analyzed and give consistent results. The method with the smallest systematic uncertainties yields an amplitude attenuation coefficient alpha = 3.20 \pm 0.57 km^(-1) between 10 and 30 kHz, considerably larger than previous theoretical estimates. Expressed as an attenuation length, the analyses give a consistent result for lambda = 1/alpha of ~1/300 m with 20% uncertainty. No significant depth or …
Study of Large Hemispherical Photomultiplier Tubes for the ANTARES Neutrino Telescope
The ANTARES neutrino telescope, to be immersed depth in the Mediterranean Sea, will consist of a 3 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 PMT chosen for ANTARES.
First search for atmospheric and extraterrestrial neutrino-induced cascades with the IceCube detector
We report on the first search for atmospheric and for diffuse astrophysical neutrino-induced showers (cascades) in the IceCube detector using 257 days of data collected in the year 2007-2008 with 22 strings active. A total of 14 events with energies above 16 TeV remained after event selections in the diffuse analysis, with an expected total background contribution of $8.3\pm 3.6$. At 90% confidence we set an upper limit of $E^2\Phi_{90%CL}<3.6\times10^{-7} GeV \cdot cm^{-2} \cdot s^{-1}\cdot sr^{-1} $ on the diffuse flux of neutrinos of all flavors in the energy range between 24 TeV and 6.6 PeV assuming that $\Phi \propto E^{-2}$ and that the flavor composition of the $\nu_e : \nu_\mu : \nu…
A Search for a Diffuse Flux of Astrophysical Muon Neutrinos with the IceCube 40-String Detector
The IceCube Neutrino Observatory is a 1 km$^{3}$ detector currently taking data at the South Pole. One of the main strategies used to look for astrophysical neutrinos with IceCube is the search for a diffuse flux of high-energy neutrinos from unresolved sources. A hard energy spectrum of neutrinos from isotropically distributed astrophysical sources could manifest itself as a detectable signal that may be differentiated from the atmospheric neutrino background by spectral measurement. This analysis uses data from the IceCube detector collected in its half completed configuration which operated between April 2008 and May 2009 to search for a diffuse flux of astrophysical muon neutrinos. A to…
An absence of neutrinos associated with cosmic-ray acceleration in gamma-ray bursts
Gamma-Ray Bursts (GRBs) have been proposed as a leading candidate for acceleration of ultra high-energy cosmic rays, which would be accompanied by emission of TeV neutrinos produced in proton-photon interactions during acceleration in the GRB fireball. Two analyses using data from two years of the IceCube detector produced no evidence for this neutrino emission, placing strong constraints on models of neutrino and cosmic-ray production in these sources.
Background studies for acoustic neutrino detection at the South Pole
The detection of acoustic signals from ultra-high energy neutrino interactions is a promising method to measure the tiny flux of cosmogenic neutrinos expected on Earth. The energy threshold for this process depends strongly on the absolute noise level in the target material. The South Pole Acoustic Test Setup (SPATS), deployed in the upper part of four boreholes of the IceCube Neutrino Observatory, has monitored the noise in Antarctic ice at the geographic South Pole for more than two years down to 500 m depth. The noise is very stable and Gaussian distributed. Lacking an in-situ calibration up to now, laboratory measurements have been used to estimate the absolute noise level in the 10 to …
Calibration and Characterization of the IceCube Photomultiplier Tube
Over 5,000 PMTs are being deployed at the South Pole to compose the IceCube neutrino observatory. Many are placed deep in the ice to detect Cherenkov light emitted by the products of high-energy neutrino interactions, and others are frozen into tanks on the surface to detect particles from atmospheric cosmic ray showers. IceCube is using the 10-inch diameter R7081-02 made by Hamamatsu Photonics. This paper describes the laboratory characterization and calibration of these PMTs before deployment. PMTs were illuminated with pulses ranging from single photons to saturation level. Parameterizations are given for the single photoelectron charge spectrum and the saturation behavior. Time resoluti…
Search for dark matter from the Galactic halo with the IceCube neutrino telescope
Self-annihilating or decaying dark matter in the Galactic halo might produce high energy neutrinos detectable with neutrino telescopes. We have conducted a search for such a signal using 276 days of data from the IceCube 22-string configuration detector acquired during 2007 and 2008. The effect of halo model choice in the extracted limit is reduced by performing a search that considers the outer halo region and not the Galactic Center. We constrain any large-scale neutrino anisotropy and are able to set a limit on the dark matter self-annihilation cross section of ⟨σAv⟩≃10-22 cm3 s-1 for weakly interacting massive particle masses above 1 TeV, assuming a monochromatic neutrino line spectrum.
Search for a Lorentz-violating sidereal signal with atmospheric neutrinos in IceCube
A search for sidereal modulation in the flux of atmospheric muon neutrinos in IceCube was performed. Such a signal could be an indication of Lorentz-violating physics. Neutrino oscillation models, derivable from extensions to the Standard Model, allow for neutrino oscillations that depend on the neutrino's direction of propagation. No such direction-dependent variation was found. A discrete Fourier transform method was used to constrain the Lorentz and CPT-violating coefficients in one of these models. Due to the unique high energy reach of IceCube, it was possible to improve constraints on certain Lorentz-violating oscillations by three orders of magnitude with respect to limits set by oth…
IceCube Sensitivity for Low-Energy Neutrinos from Nearby Supernovae ( Corrigendum )
Keywords: neutrinos ; supernovae: general ; instrumentation: detectors ; errata ; addenda Reference EPFL-ARTICLE-198916doi:10.1051/0004-6361/201117810eView record in Web of Science Record created on 2014-05-19, modified on 2017-05-12
Constraints on the extremely-high energy cosmic neutrino flux with the IceCube 2008-2009 data
We report on a search for extremely-high energy neutrinos with energies greater than $10^6$ GeV using the data taken with the IceCube detector at the South Pole. The data was collected between April 2008 and May 2009 with the half completed IceCube array. The absence of signal candidate events in the sample of 333.5 days of livetime significantly improves model independent limit from previous searches and allows to place a limit on the diffuse flux of cosmic neutrinos with an $E^{-2}$ spectrum in the energy range $2.0 \times 10^{6}$ $-$ $6.3 \times 10^{9}$ GeV to a level of $E^2 \phi \leq 3.6 \times 10^{-8}$ ${\rm GeV cm^{-2} sec^{-1}sr^{-1}}$.
Multi-year search for dark matter annihilations in the Sun with the AMANDA-II and IceCube detectors
A search for an excess of muon-neutrinos from dark matter annihilations in the Sun has been performed with the AMANDA-II neutrino telescope using data collected in 812 days of livetime between 2001 and 2006 and 149 days of livetime collected with the AMANDA-II and the 40-string configuration of IceCube during 2008 and early 2009. No excess over the expected atmospheric neutrino background has been observed. We combine these results with the previously published IceCube limits obtained with data taken during 2007 to obtain a total livetime of 1065 days. We provide an upper limit at 90% confidence level on the annihilation rate of captured neutralinos in the Sun, as well as the corresponding …
Measurement of the atmospheric neutrino energy spectrum from 100 GeV to 400 TeV with IceCube
A measurement of the atmospheric muon neutrino energy spectrum from 100 GeV to 400 TeV was performed using a data sample of about 18,000 up-going atmospheric muon neutrino events in IceCube. Boosted decision trees were used for event selection to reject mis-reconstructed atmospheric muons and obtain a sample of up-going muon neutrino events. Background contamination in the final event sample is less than one percent. This is the first measurement of atmospheric neutrinos up to 400 TeV, and is fundamental to understanding the impact of this neutrino background on astrophysical neutrino observations with IceCube. The measured spectrum is consistent with predictions for the atmospheric muon ne…
Search for neutrino-induced cascades with five years of AMANDA data
Contains fulltext : 97339.pdf (Publisher’s version ) (Closed access) We report on the search for electromagnetic and hadronic showers ("cascades") produced by a diffuse flux of extraterrestrial neutrinos in the AMANDA neutrino telescope. Data for this analysis were recorded during 1001 days of detector livetime in the years 2000-2004. The observed event rates are consistent with the background expectation from atmospheric neutrinos and muons. An upper limit is derived for the diffuse flux of neutrinos of all flavors assuming a flavor ratio of v(e):v(mu):v(tau) = 1:1:1 at the detection site. The all-flavor flux of neutrinos with an energy spectrum Phi proportional to E(-2) is less than 5.0 x…
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.