305 research outputs found

    On the Velocity of Light Signals in the Deep Underwater Neutrino Experiments

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    During the last few years deep underwater neutrino telescopes of a new generation with dimensions close to 100 m or more were taken into operation. For the correct track reconstruction and for the interpretation of light pulses from calibration lasers one has to use the group velocity for light signals. The difference between group velocity leads to an additional delay of about 10 ns for a distance of 100 m between light source and photjmultiplier. From the time of the appearance of the first projects of deep underwater neutrino telescopes in the middle of 70th this fact was never mentioned in the literature.Comment: 4 pages, 2 figure

    High Energy Neutrino Astronomy: WIN 99

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    Although high energy neutrino astronomy is a multidisciplinary science, gamma ray bursts have become the theoretical focus since recent astronomical observations revealed their potential as cosmic particle accelerators. This spotlight is shared with investigations of the potential of high energy telescopes to observe oscillating atmospheric neutrinos. The Superkamiokande results have boosted atmospheric neutrinos from a calibration tool and a background for doing astronomy, to an opportunity to confirm the evidence for neutrino mass. Nevertheless, the highlights are mostly on the experimental front with the completion of the first-generation Baikal and AMANDA detectors. Neutrino signals from the Lake Baikal detector bode well for the flurry of activities in the Mediterranean. The completed AMANDA telescope announced first light, neutrinos actually, at this meeting.Comment: 14 pages, Latex2.09, uses sprocl.sty and epsf.sty, 5 postscript figures. Talk presented at the 17th International Workshop on Weak Interactions and Neutrinos, Cape Town, South Africa, January 199

    Measurements of group velocity of light in the lake Baikal water

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    The results of direct measurements of group velocity of light in the lake Baikal water at the depth of 1100 m are presented. The lake Baikal water dispersion has been measured at three wavelengths: 370 nm, 470 nm and 525 nm. The results are in a rather good agreement with theoretical predictions.Comment: 4 pages, 5 figures, talk presented at RICH2002, to be published in NIMA; misprints corrected in formula at page

    Neutrino Telescopy in the Mediterranean Sea

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    The observation of high-energy extraterrestrial neutrinos is one of the most promising future options to increase our knowledge on non-thermal processes in the universe. Neutrinos are e.g. unavoidably produced in environments where high-energy hadrons collide; in particular this almost certainly must be true in the astrophysical accelerators of cosmic rays, which thus could be identified unambiguously by sky observations in "neutrino light". On the one hand, neutrinos are ideal messengers for astrophysical observations since they are not deflected by electromagnetic fields and interact so weakly that they are able to escape even from very dense production regions and traverse large distances in the universe without attenuation. On the other hand, their weak interaction poses a significant problem for detecting neutrinos. Huge target masses up to gigatons must be employed, requiring to instrument natural abundances of media such as sea water or antarctic ice. The first generation of such neutrino telescopes is taking data or will do so in the near future, while the second-generation projects with cubic-kilometre size is under construction or being prepared. This report focuses on status and prospects of current (ANTARES, NEMO, NESTOR) and future (KM3NeT) neutrino telescope projects in the Mediterranean Sea.Comment: Presented at 27th Int. School on Nucl. Phys. (Neutrinos in Cosmology, in Astro, Particle and Nuclear Physics), Erice/Italy, Sept. 2005; 8 pages, 7 figures. To appear in Prog. Part. Nucl. Phys. V2,V3: fixed incompatibilities of postscript figures with the arXiv softwar

    The quest for the ideal photodetector for the next generation deep-underwater neutrino telescopes

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    We review photodetectors used in present running neutrino telescopes. After a brief historical discourse, the photodetector requirements for the next generation deep underwater neutrino telescopes are discussed. It is shown that large area vacuum hybrid phototubes are the closest to the ideal photodetector for such kind of applications when compared with other vacuum phototubes.Comment: 5 pages, 5 figure

    Masses and Mixings from Neutrino Beams pointing to Neutrino Telescopes

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    We discuss the potential to determine leading oscillation parameters, the value and the sign of \Delta m^2_{31}, as well as the magnitude of \sin^2 2\theta_{13} using a conventional wide band neutrino beam pointing to water or ice Cherenkov neutrino detectors known as ``Neutrino Telescopes''. We find that precision measurements of \Delta m^2_{31} and \theta_{23} are possible and that, even though it is not possible to discriminate between charges in the detector, there is a remarkably good sensitivity to the mixing angle \theta_{13} and the sign of \Delta m^2_{31}.Comment: 9 pages, 4 figure

    The optical module of the Baikal deep underwater neutrino telescope

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    A deep underwater Cherenkov telescope has been operating since 1993 in stages of growing size at 1.1 km depth in Lake Baikal. The key component of the telescope is the Optical Module (OM) which houses the highly sensitive phototube QUASAR-370. We describe design and parameters of the QUASAR-370, the layout of the optical module, the front-end electronics and the calibration procedures, and present selected results from the five-year operation underwater. Also, future developments with respect to a telescope consisting from several thousand OMs are discussed.Comment: 30 pages, 24 figure
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