132 research outputs found

    AbschÀtzung der technischen und wirtschaftlichen Potentiale des Beitrags zur Energieversorgung und zur Minderung klimarelevanter Spurengase durch Kernenergie in der Bundesrepublik Deutschland : Studie A.4.2.a und A.4.2.b

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    In diesem Arbeitspaket A.4.2 werden die Möglichkeiten der Minderung von CO2-Emissionen durch den Einsatz der Kernenergie untersucht. Dabei werden sechs Einsatzbereiche betrachtet, in denen die Kernenergie eine CO2-Emissionsminderung durch Substitution fossiler Energieerzeugung bewirken kann. In Kapitel 2 werden mögliche CO2-Emissionsminderungen im Bereich der Stromerzeugung, in Kapitel 3 bei der Fern- bzw. NahwĂ€rmeerzeugung diskutiert. In den Kapiteln 4 bis 7 werden die CO2-Minderungspotentiale durch die Nutzung der Kernenergie zur Veredelung fossiler EnergietrĂ€ger, zur Prozeßdampf- und ProzeßwĂ€rmeerzeugung, zur Wasserstofferzeugung ĂŒber Elektrolyse und bei der tertiĂ€ren Erdölförderung in der Bundesrepublik Deutschland untersucht

    Testing Lorentz Invariance and CPT Conservation with NuMI Neutrinos in the MINOS Near Detector

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    A search for a sidereal modulation in the MINOS near detector neutrino data was performed. If present, this signature could be a consequence of Lorentz and CPT violation as predicted by a class of extensions to the Standard Model. No evidence for a sidereal signal in the data set was found, implying that there is no significant change in neutrino propagation that depends on the direction of the neutrino beam in a sun-centered inertial frame. Upper limits on the magnitudes of the Lorentz and CPT violating terms in these extensions to the Standard Model lie between 0.01-1% of the maximum expected, assuming a suppression of these signatures by factor of 10−1710^{-17}.

    A Study of Muon Neutrino Disappearance Using the Fermilab Main Injector Neutrino Beam

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    We report the results of a search for muon-neutrino disappearance by the Main Injector Neutrino Oscillation Search. The experiment uses two detectors separated by 734 km to observe a beam of neutrinos created by the Neutrinos at the Main Injector facility at Fermi National Accelerator Laboratory. The data were collected in the first 282 days of beam operations and correspond to an exposure of 1.27e20 protons on target. Based on measurements in the Near Detector, in the absence of neutrino oscillations we expected 336 +/- 14 muon-neutrino charged-current interactions at the Far Detector but observed 215. This deficit of events corresponds to a significance of 5.2 standard deviations. The deficit is energy dependent and is consistent with two-flavor neutrino oscillations according to delta m-squared = 2.74e-3 +0.44/-0.26e-3 eV^2 and sin^2(2 theta) > 0.87 at 68% confidence level.Comment: In submission to Phys. Rev.

    Measurement of neutrino velocity with the MINOS detectors and NuMI neutrino beam

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    The velocity of a ~3 GeV neutrino beam is measured by comparing detection times at the near and far detectors of the MINOS experiment, separated by 734 km. A total of 473 far detector neutrino events was used to measure (v-c)/c=5.12.910-5 (at 68% C.L.). By correlating the measured energies of 258 charged-current neutrino events to their arrival times at the far detector, a limit is imposed on the neutrino mass of mnu<50 MeV/c2 (99% C.L.)

    Measurement of the Atmospheric Muon Charge Ratio at TeV Energies with MINOS

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    The 5.4 kton MINOS far detector has been taking charge-separated cosmic ray muon data since the beginning of August, 2003 at a depth of 2070 meters-water-equivalent in the Soudan Underground Laboratory, Minnesota, USA. The data with both forward and reversed magnetic field running configurations were combined to minimize systematic errors in the determination of the underground muon charge ratio. When averaged, two independent analyses find the charge ratio underground to be 1.374 +/- 0.004 (stat.) +0.012 -0.010(sys.). Using the map of the Soudan rock overburden, the muon momenta as measured underground were projected to the corresponding values at the surface in the energy range 1-7 TeV. Within this range of energies at the surface, the MINOS data are consistent with the charge ratio being energy independent at the two standard deviation level. When the MINOS results are compared with measurements at lower energies, a clear rise in the charge ratio in the energy range 0.3 -- 1.0 TeV is apparent. A qualitative model shows that the rise is consistent with an increasing contribution of kaon decays to the muon charge ratio.Comment: 16 pages, 17 figure

    The age, origin and emplacement of the Tsiknias Ophiolite, Tinos, Greece

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    The Tsiknias Ophiolite, exposed at the highest structural levels of Tinos, Greece, represents a thrust sheet of Tethyan oceanic crust and upper mantle emplaced onto the Attic‐Cycladic Massif. We present new field observations and a new geological map of Tinos, integrated with petrology, THERMOCALC phase diagram modelling, U–Pb geochronology and whole rock geochemistry, resulting in a tectono‐thermal model that describes the formation and emplacement of the Tsiknias Ophiolite and newly identified underlying metamorphic sole. The ophiolite comprises a succession of partially dismembered and structurally repeated ultramafic and gabbroic rocks that represent the Moho Transition Zone. A plagiogranite dated by U‐Pb zircon at 161.9 ± 2.8 Ma, reveals that the Tsiknias Ophiolite formed in a supra‐subduction zone setting, comparable to the “East‐Vardar Ophiolites”, and was intruded by gabbros at 144.4 ± 5.6 Ma. Strongly sheared metamorphic sole rocks show a condensed and inverted metamorphic gradient, from partially anatectic amphibolites at P–T conditions of ca. 8.5 kbar 850‐600 °C, down‐structural section to greenschist‐facies oceanic metasediments over ~250 m. Leucosomes generated by partial melting of the uppermost sole amphibolite, yielded a U–Pb zircon protolith age of ca. 190 Ma and a high‐grade metamorphic‐anatectic age of 74.0 ± 3.5 Ma associated with ophiolite emplacement. The Tsiknias Ophiolite was therefore obducted ~90 Myrs after it formed during initiation of a NE‐dipping intra‐oceanic subduction zone to the northeast of the Cyclades that coincides with Africa's plate motion changing from transcurrent to convergent. Continued subduction resulted in high‐pressure metamorphism of the Cycladic continental margin ~25 Myrs later

    First observations of separated atmospheric nu_mu and bar{nu-mu} events in the MINOS detector

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    The complete 5.4 kton MINOS far detector has been taking data since the beginning of August 2003 at a depth of 2070 meters water-equivalent in the Soudan mine, Minnesota. This paper presents the first MINOS observations of nu” and [overline nu ]” charged-current atmospheric neutrino interactions based on an exposure of 418 days. The ratio of upward- to downward-going events in the data is compared to the Monte Carlo expectation in the absence of neutrino oscillations, giving Rup/downdata/Rup/downMC=0.62-0.14+0.19(stat.)±0.02(sys.). An extended maximum likelihood analysis of the observed L/E distributions excludes the null hypothesis of no neutrino oscillations at the 98% confidence level. Using the curvature of the observed muons in the 1.3 T MINOS magnetic field nu” and [overline nu ]” interactions are separated. The ratio of [overline nu ]” to nu” events in the data is compared to the Monte Carlo expectation assuming neutrinos and antineutrinos oscillate in the same manner, giving R[overline nu ][sub mu]/nu[sub mu]data/R[overline nu ][sub mu]/nu[sub mu]MC=0.96-0.27+0.38(stat.)±0.15(sys.), where the errors are the statistical and systematic uncertainties. Although the statistics are limited, this is the first direct observation of atmospheric neutrino interactions separately for nu” and [overline nu ]”

    Long-Baseline Neutrino Facility (LBNF) and Deep Underground Neutrino Experiment (DUNE) Conceptual Design Report Volume 2: The Physics Program for DUNE at LBNF

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    The Physics Program for the Deep Underground Neutrino Experiment (DUNE) at the Fermilab Long-Baseline Neutrino Facility (LBNF) is described