Search results for "Zenith"
showing 10 items of 96 documents
Search for gamma ray bursts with the ARGO-YBJ detector in scaler mode
2009
We report on the search for Gamma Ray Bursts (GRBs) in the energy range 1-100 GeV in coincidence with the prompt emission detected by satellites using the Astrophysical Radiation with Ground-based Observatory at YangBaJing (ARGO-YBJ) air shower detector. Thanks to its mountain location (Yangbajing, Tibet, P.R. China, 4300 m a.s.l.), active surface (about 6700 m**2 of Resistive Plate Chambers), and large field of view (about 2 sr, limited only by the atmospheric absorption), the ARGO-YBJ air shower detector is particularly suitable for the detection of unpredictable and short duration events such as GRBs. The search is carried out using the "single particle technique", i.e. counting all the …
Size of the dark side of the solar neutrino parameter space
2000
We present an analysis of the MSW neutrino oscillation solutions of the solar neutrino problem in the framework of two-neutrino mixing in the enlarged parameter space $(\ensuremath{\Delta}{m}^{2},{\mathrm{tan}}^{2}\ensuremath{\theta})$ with $\ensuremath{\theta}\ensuremath{\in}(0,\ensuremath{\pi}/2).$ Recently, it was pointed out that the allowed region of parameters from a fit to the measured total rates can extend to values $\ensuremath{\theta}g~\ensuremath{\pi}/4$ (the so-called ``dark side'') when higher confidence levels are allowed. The purpose of this Rapid Communication is to reanalyze the problem, including all the solar neutrino data available, to discuss the dependence on the stat…
10.2 Discrete Symmetries
2008
1. The asymmetry of the zenith angle distribution of νμ of Super-Kamiokande is the direct evidence of νμ oscillations. 2. The first oscillation minimum was observed in the L/E distribution using the high resolution L/E sample of Super-Kamiokande. It confirms that the distortion of the zenith angle distribution is really due to neutrino oscillations and excludes other hypotheses such as neutrino decay and decoherence model. 3. A search for charged current (CC) interaction of ντ shows a 2.4σ excess of signal and the observed number of events is consistent with the expectation. 4. No indication of νe oscillation is observed so far in atmospheric neutrinos.
Influence of solar and sensor angles on chlorophyll estimation for geostationary ocean color imager
2012
The impact of the solar and sensor angles on band-ratio chlorophyll concentration (Chl) estimation in Case 1 waters (open ocean) is analyzed in this work. The error range of Chl estimation due to angular variation is evaluated. The radiative transfer code Hydrolight is used for remote sensing reflectance simulation for 20 spectral bands. OC4v4 algorithm is used for Chl estimation. The results indicate that the error range of Chl estimation is between -41.91% and +46.15% when Chl range is from 0.0425 mg/m 3 to 10.6685 mg/m 3 and the solar and sensor zenith angles vary between 0 and 80°. This study provides a reference to determine the effective observation area of a future multispectral or h…
Optimization of a polarization imaging system for 3D measurements of transparent objects
2009
This paper presents a multispectral imaging system for 3D reconstruction of transparent objects based on "shape from polarization" technique. The originality of this work relies on a multispectral active lighting system which enables to cope with the two ambiguities on the zenith angle and azimuth angle. A calibration step allows optimising the polarimetric measurements. Example of a reconstructed transparent object is presented.
Measurements of total ozone amount over Badajoz (Southwestern Spain) by means of a GUV multiband radiometer
2012
This paper presents the first measurements of total ozone amount performed at the radiometric station of Badajoz (Spain) by means of a multichannel radiometer GUV-2511. The retrieval of total ozone amount from GUV measurements of solar ultraviolet irradiance is performed with the support of look-up tables calculated using the SBDART radiation transfer code. This methodology is based on the different absorption by ozone suffered by the radiation at two certain near wavelengths. In this case the pair 305, 340 nm was chosen because of its better performance than the pair 305, 320 nm. The look-up table contains the ratio between irradiances at the mentioned wavelengths calculated under differen…
Searches for Sterile Neutrinos with the IceCube Detector
2016
The IceCube neutrino telescope at the South Pole has measured the atmospheric muon neutrino spectrum as a function of zenith angle and energy in the approximate 320 GeV to 20 TeV range, to search for the oscillation signatures of light sterile neutrinos. No evidence for anomalous $\nu_\mu$ or $\bar{\nu}_\mu$ disappearance is observed in either of two independently developed analyses, each using one year of atmospheric neutrino data. New exclusion limits are placed on the parameter space of the 3+1 model, in which muon antineutrinos would experience a strong MSW-resonant oscillation. The exclusion limits extend to $\mathrm{sin}^2 2\theta_{24} \leq$ 0.02 at $\Delta m^2 \sim$ 0.3 $\mathrm{eV}^…
Sedimentation and Fouling of Optical Surfaces at the ANTARES Site
2003
ANTARES is a project leading towards the construction and deployment of a neutrino telescope in the deep Mediterranean Sea. The telescope will use an array of photomultiplier tubes to detect the Cherenkov light emitted by muons resulting from the interaction with matter of high energy neutrinos. In the vicinity of the deployment site the ANTARES collaboration has performed a series of in-situ measurements to study the change in light transmission through glass surfaces during immersions of several months. The average loss of light transmission is estimated to be only ~2% at the equator of a glass sphere one year after deployment. It decreases with increasing zenith angle, and tends to satur…
Extraction of the Muon Signals Recorded with the Surface Detector of the Pierre Auger Observatory Using Recurrent Neural Networks
2021
The Pierre Auger Observatory, at present the largest cosmic-ray observatory ever built, is instrumented with a ground array of 1600 water-Cherenkov detectors, known as the Surface Detector (SD). The SD samples the secondary particle content (mostly photons, electrons, positrons and muons) of extensive air showers initiated by cosmic rays with energies ranging from $10^{17}~$eV up to more than $10^{20}~$eV. Measuring the independent contribution of the muon component to the total registered signal is crucial to enhance the capability of the Observatory to estimate the mass of the cosmic rays on an event-by-event basis. However, with the current design of the SD, it is difficult to straightfo…
Cosmic-ray muon flux at Canfranc Underground Laboratory
2019
Residual flux and angular distribution of high-energy cosmic muons have been measured in two underground locations at the Canfranc Underground Laboratory (LSC) using a dedicated Muon Monitor. The instrument consists of three layers of fast scintillation detector modules operating as 352 independent pixels. The monitor has flux-defining area of 1 m${}^{2}$, covers all azimuth angles, and zenith angles up to $80^\circ$. The measured integrated muon flux is $(5.26 \pm 0.21) \times 10^{-3}$ m${}^{-2}$s${}^{-1}$ in the Hall A of the LAB2400 and $(4.29 \pm 0.17) \times 10^{-3}$ m${}^{-2}$s${}^{-1}$ in LAB2500. The angular dependence is consistent with the known profile and rock density of the sur…