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Search Results: 1 - 10 of 12267 matches for " Double Chooz collaboration "
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Status Report on Double Chooz
A. Portaa,for the Double Chooz collaboration
Physics , 2009,
Abstract: Double Chooz main target is to measure Theta13 oscillation parameter by comparing reactor neutrino fluxes in two identical detectors located respectively at 400 m and 1 km away from the 2 Chooz reactor cores. The far detector is now under construction, while we have just completed the design phase of the near one. In this report I will discuss the detector principle, sensitivity and its present construction status.
A High Precision Reactor Neutrino Detector for the Double Chooz Experiment
Fumihiko Suekane,for the Double Chooz Collaboration
Physics , 2009, DOI: 10.1016/j.nima.2010.03.029
Abstract: Double Chooz is a reactor neutrino experiment which investigates the last neutrino mixing angle; theta-13. It is necessary to measure reactor neutrino disappearance with precision 1% or better to detect finite value of theta-13. This requirement is the most strict compared to other reactor neutrino experiments performed so far. The Double Chooz experiment makes use of a number of techniques to reduce the possible errors to achieve the sensitivity. The detector is now under construction and it is expected to take first neutrino data in 2009 and to measure sin^22theta-13 with a sensitivity of 0.03 (90%C.L.) In this proceedings, the technical concepts of Double Chooz detector are explained stressing on how it copes with the systematic errors.
Latest News from Double Chooz Reactor Neutrino Experiment
Masahiro Kuze,for Double Chooz Collaboration
Physics , 2011, DOI: 10.1063/1.3700585
Abstract: Double Chooz experiment will search for a disappearance of the reactor neutrinos from Chooz reactor cores in Ardenne, France, in order to detect the yet unknown neutrino oscillation angle \theta 13. The far detector was completed in 2010 and data-taking has started in spring 2011. Status of data-taking is presented and some performance plots from physics data are shown in this paper for the first time. Also the prospect of experimental sensitivity is presented, in light of recent indication from T2K for a non-zero \theta 13 value.
Rate-Only analysis with reactor-off data in the Double Chooz experiment
P. Novella,for the Double Chooz collaboration
Physics , 2013,
Abstract: Among ongoing reactor-based experiments, Double Chooz is unique in obtaining data when the reactor cores are brought down for maintenance. These reactor-off data allow for a clean measurement of the backgrounds of the experiment, thus being of uppermost importance for the theta13 oscillation analysis. While the oscillation results published by the collaboration in 2011 and 2012 rely on background models derived from reactor-on data, in this talk we present an independent study based on the handle provided by 7.53 days of reactor-off data. A global fit to both theta13 and the total background is performed by analyzing the observed neutrino rate as a function of the non-oscillated expected rate for different reactor power conditions. The result presented in this talk is fully consistent with the one already published by Double Chooz. As they both yield almost the same precision, this work stands as a prove of the reliability of the background estimates and the oscillation analysis of the experiment.
Double Chooz: results towards the near detector phase
P. Novella,for the Double Chooz collaboration
Physics , 2014,
Abstract: Since the first indication in 2011 of a non-vanishing value of $\theta_{13}$ using reactor neutrinos by Double Chooz, this collaboration has developed new analyses leading to an increased precision on $\theta_{13}$ and different cross-checks of the oscillation results. Beyond the update of the analysis based on neutron captures on Gd in 2012, Double Chooz has also released a consistent measurement of $\theta_{13}$ by means of neutron captures on H. The combination of the n-Gd and n-H data samples, as well as 7.23 days of reactor off data, in a global rate+shape analysis yields $\sin^22\theta_{13} = 0.109\pm 0.035$. This measurement has been validated with a new background-model-independent approach, which compares the observed and expected neutrino rates as a function of reactor power. This Reactor Rate Modulation analysis yields $\sin^22\theta_{13} = 0.102\pm 0.043$ when combining the n-Gd and n-H samples. The Double Chooz collaboration is currently developing a new analysis increasing the signal-to-background ratio while reducing the background and detection systematics. This new approach is being prepared as a first step of the new phase of the experiment that will begin in summer 2014 with the operation of a near detector.
Double Chooz: Searching for theta13 with reactor neutrinos
P. Novella,for the Double Chooz collaboration
Physics , 2011,
Abstract: The Double Chooz experiment is meant to search for the neutrino mixing angle theta13 taking advantage of the neutrinos generated at the nuclear power plant of Chooz. Double Chooz relies on neutrino flux measurements at two different locations, the so-called far and near detectors, although the first phase runs only with the far detector. The commissioning of the far detector started in January 2011 and first results improving the current limit on theta13 are expected by the summer 2011. The status of the Double Chooz experiment is presented.
Studying Neutrino Directionality with Double Chooz
Erica Caden,for the Double Chooz collaboration
Physics , 2012,
Abstract: The first results from Double Chooz with 100 days of data measured $\sin^2(2\theta_{13}) = 0.086 \pm 0.051$. Backgrounds contribute significantly to the systematic uncertainty budget. Using the incoming neutrino directionality we will attempt to further separate the inverse beta decay signal from backgrounds. The CHOOZ experiment completed a similar analysis and found that the neutrino source can be located to within a cone of half-aperture of 18 degrees at the 68% C.L. We study the possible improvement of this result by Double Chooz.
Double Chooz: Optimizing CHOOZ for a possible theta 13 measurement
S. A. Dazeley,for the Double Chooz Collaboration
Physics , 2005,
Abstract: The proposed Double Chooz theta 13 experiment is described. Double Chooz will be an optimized reactor disappearance experiment similar to the original CHOOZ. The optimization includes an increase in the signal to noise by increasing the target volume to twice the original CHOOZ, reducing singles background with a non-scintillating oil buffer region around the target and carefully controlling systematic uncertainties by measuring the electron antineutrino flux of the source with a near detector. The Double Chooz far detector will be situated in the same cavern as CHOOZ but will detect ~50000 electron antineutrinos in three years of operation. We estimate a systematic uncertainty of 0.6%, and a reduction of the upper limit on theta 13 to 5 degrees.
First result from the Double Chooz reactor-neutrino experiment
Tsunayuki Matsubara,on behalf of the Double Chooz collaboration
Statistics , 2012,
Abstract: We report first results of a search for the non-zero neutrino mixing angle \theta_{13} from the Double Chooz experiment. Double Chooz aims to measure the mixing angle based on anti-electron-neutrino disappearance as a consequence of neutrino oscillation. A new generation of anti-electron-neutrino detector having 10 m^3 fiducial volume is located 1 km from the two 4.25 GW_{th} reactors at the Chooz Power Plant in France. Physics data taking has been continuing since April 2011. A ratio of observed-to-predicted event rate of 0.944 +/- 0.016 (stat) +/- 0.040 (syst) was obtained in 101 days of detector running. Analyzing both the rate and their energy spectral shape, we found sin^{2}2\theta_{13} = 0.086 +/- 0.041 (stat) +/- 0.030 (syst) at \Delta m^2_{atm} = 2.4 x 10^{-3} eV^2.
Double Chooz: Latest results
J. I. Crespo-Anadón,for the Double Chooz collaboration
Physics , 2014,
Abstract: The latest results from the Double Chooz experiment on the neutrino mixing angle $\theta_{13}$ are presented. A detector located at an average distance of 1050 m from the two reactor cores of the Chooz nuclear power plant has accumulated a live time of 467.90 days, corresponding to an exposure of 66.5 GW-ton-year (reactor power $\times$ detector mass $\times$ live time). A revised analysis has boosted the signal efficiency and reduced the backgrounds and systematic uncertainties compared to previous publications, paving the way for the two detector phase. The measured $\sin^2 2\theta_{13} = 0.090^{+0.032}_{-0.029}$ is extracted from a fit to the energy spectrum. A deviation from the prediction above a visible energy of 4 MeV is found, being consistent with an unaccounted reactor flux effect, which does not affect the $\theta_{13}$ result. A consistent value of $\theta_{13}$ is measured in a rate-only fit to the number of observed candidates as a function of the reactor power, confirming the robustness of the result.
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