Browsing by Subject "Supernova"

Now showing 1 - 3 of 3
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    Analytical and numerical studies of neutrino oscillations in supernovae
    (2012-10) Wu, Meng-Ru
    Neutrinos are one of the central ingredients in core-collapse supernova explosion and their flavor oscillations in supernovae might affect many processes that occur in this explosive environment. In this thesis, we study neutrino flavor oscillations in supernovae both analytically and numerically. Analytically, we propose a simple model to explain the flavor evolution history in the region of collective neutrino oscillations during the neutronization neutrino burst and accretion phase of neutrino emission with low matter density. We show that the formation of spectral splits induced by collective neutrino oscillations can be well-understood using this model. We also apply this model to discuss the flavor instability of neutrino oscillations that occurs in the cooling phase. Numerically, we simulate neutrino flavor evolution history using the neutrino emission data from a state-of-the-art 18 M⊙ supernova model. We discuss the time-dependence of neutrino oscillations on neutrino emission characteristics and the supernova environment. We then study the effect of neutrino oscillations on the nucleosynthesis that occurs in the neutrino-driven wind. At last, we calculate the expected neutrino signals in the IceCube detector and discuss the consequences.
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    Neutrino-induced neucleosynthesis in supernova helium shells.
    (2011-08) Banerjee, Projjwal
    We re-examine a neutrino-driven r-process mechanism in the helium shell of a core-collapse supernova. We analyze the pre-shock evolution in detail using recent stellar models. In addition we perform full hydrodynamic simulations including the effect of shock, finding that the outer helium shells can be the site for an r-process. We find that this mechanism could succeed in early stars of metallicity . 10−3 the solar value, at relatively low temperatures and neutron densities, producing A ∼ 130 and 195 abundance peaks over ∼ 50–60 s. The mechanism is extremely sensitive to the neutrino emission model and to neutrino oscillations. While this mechanism is not very sensitive to the explosion energy, mixing of the ejecta can be different for different explosion energies. We discuss the implications of an r-process that could alter interpretations of abundance data from metal-poor stars.
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    Under The Hood: Preparing the Helium and Lead Observatory for Full Operation
    (2014-01) Vasel, Justin
    The Helium and Lead Observatory (HALO) at SNOLAB in Canada is the world's first dedicated supernova neutrino detector. Construction of the detector is complete, but there is still work to be done before it is fully operational. In this thesis, I describe my contributions to the HALO experiment which include the testing of hardware, the design of a redundant networking scheme, and the development and implementation of a remote monitoring system.