The Experts below are selected from a list of 12114 Experts worldwide ranked by ideXlab platform
A B Balantekin - One of the best experts on this subject based on the ideXlab platform.
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improved short baseline neutrino oscillation search and energy spectrum measurement with the prospect experiment at hfir
arXiv: High Energy Physics - Experiment, 2020Co-Authors: M Andriamirado, N S Bowden, A B Balantekin, H R Band, C D Bass, Denis E Bergeron, D Berish, J P Brodsky, C D Bryan, T ClassenAbstract:We present a detailed report on sterile neutrino oscillation and U-235 antineutrino energy spectrum measurement results from the PROSPECT experiment at the highly enriched High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory. In 96 calendar days of data taken at an average baseline distance of 7.9 m from the center of the 85 MW HFIR core, the PROSPECT detector has observed more than 50,000 interactions of Antineutrinos produced in beta decays of U-235 fission products. New limits on the oscillation of Antineutrinos to light sterile neutrinos have been set by comparing the detected energy spectra of ten reactor-detector baselines between 6.7 and 9.2 meters. Measured differences in energy spectra between baselines show no statistically significant indication of Antineutrinos to sterile neutrino oscillation and disfavor the Reactor Antineutrino Anomaly best-fit point at the 2.5$\sigma$ confidence level. The reported U-235 antineutrino energy spectrum measurement shows excellent agreement with energy spectrum models generated via conversion of the measured U-235 beta spectrum, with a $\chi^2$/DOF of 31/31. PROSPECT is able to disfavor at 2.4$\sigma$ confidence level the hypothesis that U-235 Antineutrinos are solely responsible for spectrum discrepancies between model and data obtained at commercial reactor cores. A data-model deviation in PROSPECT similar to that observed by commercial core experiments is preferred with respect to no observed deviation, at a 2.2$\sigma$ confidence level.
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extraction of the 235 u and 239 pu antineutrino spectra at daya bay
Physical Review Letters, 2019Co-Authors: D Adey, A B Balantekin, H R Band, M Bishai, S Blyth, G F Cao, J Cao, D Cao, J F Chang, Y ChangAbstract:This Letter reports the first extraction of individual antineutrino spectra from ^{235}U and ^{239}Pu fission and an improved measurement of the prompt energy spectrum of reactor Antineutrinos at Daya Bay. The analysis uses 3.5×10^{6} inverse beta-decay candidates in four near antineutrino detectors in 1958 days. The individual antineutrino spectra of the two dominant isotopes, ^{235}U and ^{239}Pu, are extracted using the evolution of the prompt spectrum as a function of the isotope fission fractions. In the energy window of 4-6 MeV, a 7% (9%) excess of events is observed for the ^{235}U (^{239}Pu) spectrum compared with the normalized Huber-Mueller model prediction. The significance of discrepancy is 4.0σ for ^{235}U spectral shape compared with the Huber-Mueller model prediction. The shape of the measured inverse beta-decay prompt energy spectrum disagrees with the prediction of the Huber-Mueller model at 5.3σ. In the energy range of 4-6 MeV, a maximal local discrepancy of 6.3σ is observed.
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improved measurement of the reactor antineutrino flux and spectrum at daya bay
Chinese Physics C, 2017Co-Authors: A B Balantekin, H R Band, M Bishai, S Blyth, G F Cao, J Cao, D Cao, W R Cen, Y L ChanAbstract:A new measurement of the reactor antineutrino flux and energy spectrum by the Daya Bay reactor neutrino experiment is reported. The Antineutrinos were generated by six 2.9 GWth nuclear reactors and detected by eight antineutrino detectors deployed in two near (560 m and 600 m flux-weighted baselines) and one far (1640 m flux-weighted baseline) underground experimental halls. With 621 days of data, more than 1.2 million inverse beta decay (IBD) candidates were detected. The IBD yield in the eight detectors was measured, and the ratio of measured to predicted flux was found to be 0.946±0.020 (0.992±0.021) for the Huber+Mueller (ILL+Vogel) model. A 2.9σ deviation was found in the measured IBD positron energy spectrum compared to the predictions. In particular, an excess of events in the region of 4–6 MeV was found in the measured spectrum, with a local significance of 4.4σ. A reactor antineutrino spectrum weighted by the IBD cross section is extracted for model-independent predictions.
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the detector system of the daya bay reactor neutrino experiment
Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 2016Co-Authors: F P An, A B Balantekin, H R Band, J Z Bai, D R Beavis, W Beriguete, M Bishai, S Blyth, R L BrownAbstract:The Daya Bay experiment was the first to report simultaneous measurements of reactor Antineutrinos at multiple baselines leading to the discovery of ν¯e oscillations over km-baselines. Subsequent data has provided the world׳s most precise measurement of sin^2 2θ_(13) and the effective mass splitting Δm^2_(ee). The experiment is located in Daya Bay, China where the cluster of six nuclear reactors is among the world׳s most prolific sources of electron Antineutrinos. Multiple antineutrino detectors are deployed in three underground water pools at different distances from the reactor cores to search for deviations in the antineutrino rate and energy spectrum due to neutrino mixing. Instrumented with photomultiplier tubes, the water pools serve as shielding against natural radioactivity from the surrounding rock and provide efficient muon tagging. Arrays of resistive plate chambers over the top of each pool provide additional muon detection. The antineutrino detectors were specifically designed for measurements of the antineutrino flux with minimal systematic uncertainty. Relative detector efficiencies between the near and far detectors are known to better than 0.2%. With the unblinding of the final two detectors’ baselines and target masses, a complete description and comparison of the eight antineutrino detectors can now be presented. This paper describes the Daya Bay detector systems, consisting of eight antineutrino detectors in three instrumented water pools in three underground halls, and their operation through the first year of eight detector data-taking.
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measurement of the reactor antineutrino flux and spectrum at daya bay
Physical Review Letters, 2016Co-Authors: A B Balantekin, H R Band, M Bishai, S Blyth, I. Butorov, G F Cao, J Cao, D Cao, W R Cen, Y L ChanAbstract:This Letter reports a measurement of the flux and energy spectrum of electron Antineutrinos from six 2.9 GWth nuclear reactors with six detectors deployed in two near (effective baselines 512 and 561 m) and one far (1579 m) underground experimental halls in the Daya Bay experiment. Using 217 days of data, 296 721 and 41 589 inverse β decay (IBD) candidates were detected in the near and far halls, respectively. The measured IBD yield is (1.55±0.04) ×10(-18) cm(2) GW(-1) day(-1) or (5.92±0.14) ×10(-43) cm(2) fission(-1). This flux measurement is consistent with previous short-baseline reactor antineutrino experiments and is 0.946±0.022 (0.991±0.023) relative to the flux predicted with the Huber-Mueller (ILL-Vogel) fissile antineutrino model. The measured IBD positron energy spectrum deviates from both spectral predictions by more than 2σ over the full energy range with a local significance of up to ∼4σ between 4-6 MeV. A reactor antineutrino spectrum of IBD reactions is extracted from the measured positron energy spectrum for model-independent predictions.
J G Learned - One of the best experts on this subject based on the ideXlab platform.
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AGM2015: Antineutrino Global Map 2015
Scientific Reports, 2015Co-Authors: S.m. Usman, G.r. Jocher, W.f. Mcdonough, J G LearnedAbstract:Every second greater than 10^25 Antineutrinos radiate to space from Earth, shining like a faint antineutrino star. Underground antineutrino detectors have revealed the rapidly decaying fission products inside nuclear reactors, verified the long-lived radioactivity inside our planet and informed sensitive experiments for probing fundamental physics. Mapping the anisotropic antineutrino flux and energy spectrum advance geoscience by defining the amount and distribution of radioactive power within Earth while critically evaluating competing compositional models of the planet. We present the Antineutrino Global Map 2015 (AGM2015), an experimentally informed model of Earth’s surface antineutrino flux over the 0 to 11 MeV energy spectrum, along with an assessment of systematic errors. The open source AGM2015 provides fundamental predictions for experiments, assists in strategic detector placement to determine neutrino mass hierarchy and aids in identifying undeclared nuclear reactors. We use cosmochemically and seismologically informed models of the radiogenic lithosphere/mantle combined with the estimated antineutrino flux, as measured by KamLAND and Borexino, to determine the Earth’s total antineutrino luminosity at . We find a dominant flux of geo-neutrinos, predict sub-equal crust and mantle contributions, with ~1% of the total flux from man-made nuclear reactors.
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AGM2015: Antineutrino Global Map 2015
Scientific reports, 2015Co-Authors: Shawn Usman, W.f. Mcdonough, G.r. Jocher, Stephen T. Dye, J G LearnedAbstract:Every second greater than $10^{25}$ Antineutrinos radiate to space from Earth, shining like a faint antineutrino star. Underground antineutrino detectors have revealed the rapidly decaying fission products inside nuclear reactors, verified the long-lived radioactivity inside our planet, and informed sensitive experiments for probing fundamental physics. Mapping the anisotropic antineutrino flux and energy spectrum advance geoscience by defining the amount and distribution of radioactive power within Earth while critically evaluating competing compositional models of the planet. We present the Antineutrino Global Map 2015 (AGM2015), an experimentally informed model of Earth's surface antineutrino flux over the 0 to 11 MeV energy spectrum, along with an assessment of systematic errors. The open source AGM2015 provides fundamental predictions for experiments, assists in strategic detector placement to determine neutrino mass hierarchy, and aids in identifying undeclared nuclear reactors. We use cosmochemically and seismologically informed models of the radiogenic lithosphere/mantle combined with the estimated antineutrino flux, as measured by KamLAND and Borexino, to determine the Earth's total antineutrino luminosity at $3.4^{+2.3}_{-2.2} \times 10^{25} \bar{\nu}_e$. We find a dominant flux of geo-neutrinos, predict sub-equal crust and mantle contributions, with $\sim1\%$ of the total flux from man-made nuclear reactors.
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nuclear security applications of antineutrino detectors current capabilities and future prospects
Science & Global Security, 2010Co-Authors: A Bernstein, G Baldwin, B Boyer, M C Goodman, J G Learned, J Lund, D Reyna, R. SvobodaAbstract:Antineutrinos are electrically neutral, nearly massless fundamental particles produced in large numbers in the cores of nuclear reactors and in nuclear explosions. In the half century since their discovery, major advances in the understanding of their properties, and in detector technology, have opened the door to a new discipline—Applied Antineutrino Physics. Because Antineutrinos are inextricably linked to the process of nuclear fission, there are many applications of interest in nuclear nonproliferation. This paper presents a comprehensive survey of applied antineutrino physics relevant for nonproliferation, summarizes recent advances in the field, describes the overlap of this nascent discipline with other ongoing fundamental and applied antineutrino research, and charts a course for research and development for future applications. It is intended as a resource for policymakers, researchers, and the wider nuclear nonproliferation community.
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nuclear security applications of antineutrino detectors current capabilities and future prospects
arXiv: Nuclear Experiment, 2009Co-Authors: A Bernstein, G Baldwin, B Boyer, M C Goodman, J G Learned, J Lund, D Reyna, R. SvobodaAbstract:Antineutrinos are electrically neutral, nearly massless fundamental particles produced in large numbers in the cores of nuclear reactors and in nuclear explosions. In the half century since their discovery, major advances in the understanding of their properties, and in detector technology, have opened the door to a new discipline: Applied Antineutrino Physics. Because Antineutrinos are inextricably linked to the process of nuclear fission, many applications of interest are in nuclear nonproliferation. This white paper presents a comprehensive survey of applied antineutrino physics relevant for nonproliferation, summarizes recent advances in the field, describes the overlap of this nascent discipline with other ongoing fundamental and applied antineutrino research, and charts a course for research and development for future applications. It is intended as a resource for policymakers, researchers, and the wider nuclear nonproliferation community.
Muriel Fallot - One of the best experts on this subject based on the ideXlab platform.
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The Detection of Reactor Antineutrinos for Reactor Core Monitoring: an Overview
Nuclear Data Sheets, 2014Co-Authors: Muriel FallotAbstract:Abstract There have been new developments in the field of applied neutrino physics during the last decade. The International Atomic Energy Agency (IAEA) has expressed interest in the potentialities of antineutrino detection as a new tool for reactor monitoring and has created an ad hoc Working Group in late 2010 to follow the associated research and development. Several research projects are ongoing around the world to build antineutrino detectors dedicated to reactor monitoring, to search for and develop innovative detection techniques, or to simulate and study the characteristics of the antineutrino emission of actual and innovative nuclear reactor designs. We give, in these proceedings, an overview of the relevant properties of Antineutrinos, the possibilities of and limitations on their detection, and the status of the development of a variety of compact antineutrino detectors for reactor monitoring.
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Determination of the Sensitivity of the Antineutrino Probe for Reactor Core Monitoring
Nuclear Data Sheets, 2014Co-Authors: S. Cormon, Muriel Fallot, Van Minh Bui, A. Cucoanes, Magali Estienne, M. Lenoir, A. Onillon, T. Shiba, F. Yermia, A.-a. Zakari-issoufouAbstract:This paper presents a feasibility study of the use of the detection of reactor-Antineutrinos View the MathML source(ν¯e) for non proliferation purpose. To proceed, we have started to study different reactor designs with our simulation tools. We use a package called MCNP Utility for Reactor Evolution (MURE), initially developed by CNRS/IN2P3 labs to study Generation IV reactors. The MURE package has been coupled to fission product beta decay nuclear databases for studying reactor antineutrino emission. This method is the only one able to predict the antineutrino emission from future reactor cores, which don't use the thermal fission of 235U, 239Pu and 241Pu. It is also the only way to include off-equilibrium effects, due to neutron captures and time evolution of the fission product concentrations during a reactor cycle. We will present here the first predictions of antineutrino energy spectra from innovative reactor designs (Generation IV reactors). We will then discuss a summary of our results of non-proliferation scenarios involving the latter reactor designs, taking into account reactor physics constraints.
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Nuclear reactor simulations for unveiling diversion scenarios : capabilities of the antineutrino probe
2009Co-Authors: Muriel Fallot, Benoît Guillon, Thierry Lasserre, Alain Letourneau, M. Cribier, Michael Fechner, Lydie Giot, Daniel Lhuillier, J Martino, G. MentionAbstract:Nuclear reactors emit a huge amount of electronic Antineutrinos, arising from the fission product decay. Reactor Antineutrinos thus posess unique features that place them as a potential new safeguards tool for the International Atomic Energy Agency (IAEA). Indeed, they carry outside the core the direct picture of its isotopic fission rates, thus opening the possibility of a remote, non-intrusive and tamperproof reactor monitoring. Sophisticated simulations of reactors and their associated antineutrino flux and energy spectrum have been developed to predict the neutrino signature of the fuel burnup and of a diversion. The only user-defined inputs driving the time evolution of the isotopic composition of the core are the initial fuel composition, the refueling scheme, and the thermal power. The evolution of the antineutrino flux and energy spectrum with the fuel burnup, as well as the effect of neutron capture on various nuclei are taken into account. Non-proliferation scenarios and burnup monitoring with Antineutrinos have been studied using these tools for PWR and CANDU reactors. A full core simulation of an N4-PWR will be presented in a first part. Gross unveiling diversion scenarios using a PWR have been simulated in order to test the ability of the antineutrino probe. A channel of a Heavy Water Reactor (CANDU 600) loaded with natural Uranium, has been simulated also in order to provide a first hint of what antineutrino detection would bring to the monitoring of such on-line refueled reactor which are maintained in a steady state through quasi-continuous refueling. Very simple proliferation scenario studies with CANDU reactors, based on several channel calculations, made at various fuel dwell-times, will be shown in a second part. In both cases, the response of a Nucifer-like detector placed at 25m from the core to these scenarios has been studied.
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Towards reactor neutrino applied physics
2007Co-Authors: Muriel Fallot, M. Cribier, Lydie Giot, Daniel Lhuillier, S. Cormon, B. Guillon, T. Lasserre, A. Letourneau, J MartinoAbstract:Nuclear power plants are intense sources of Antineutrinos. Their energy spectrum and emitted flux depend on the composition of the nuclear fuel and on the thermal power of the reactor. These properties led to potential applications of neutrino physics: they could be used to non intrusively monitor a nuclear reactor. To this purpose, a better knowledge of the antineutrino energy spectra arising from uranium and plutonium isotope fission is necessary. In these proceedings we relate about on-going simulation efforts aiming at reducing the errors associated to these spectra. The generic tools under development and presented below will allow to perform scenario studies on the feasibility of using Antineutrinos to measure thermal power and to test to which precision the fuel composition can be deduced using these particles.
H R Band - One of the best experts on this subject based on the ideXlab platform.
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improved short baseline neutrino oscillation search and energy spectrum measurement with the prospect experiment at hfir
arXiv: High Energy Physics - Experiment, 2020Co-Authors: M Andriamirado, N S Bowden, A B Balantekin, H R Band, C D Bass, Denis E Bergeron, D Berish, J P Brodsky, C D Bryan, T ClassenAbstract:We present a detailed report on sterile neutrino oscillation and U-235 antineutrino energy spectrum measurement results from the PROSPECT experiment at the highly enriched High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory. In 96 calendar days of data taken at an average baseline distance of 7.9 m from the center of the 85 MW HFIR core, the PROSPECT detector has observed more than 50,000 interactions of Antineutrinos produced in beta decays of U-235 fission products. New limits on the oscillation of Antineutrinos to light sterile neutrinos have been set by comparing the detected energy spectra of ten reactor-detector baselines between 6.7 and 9.2 meters. Measured differences in energy spectra between baselines show no statistically significant indication of Antineutrinos to sterile neutrino oscillation and disfavor the Reactor Antineutrino Anomaly best-fit point at the 2.5$\sigma$ confidence level. The reported U-235 antineutrino energy spectrum measurement shows excellent agreement with energy spectrum models generated via conversion of the measured U-235 beta spectrum, with a $\chi^2$/DOF of 31/31. PROSPECT is able to disfavor at 2.4$\sigma$ confidence level the hypothesis that U-235 Antineutrinos are solely responsible for spectrum discrepancies between model and data obtained at commercial reactor cores. A data-model deviation in PROSPECT similar to that observed by commercial core experiments is preferred with respect to no observed deviation, at a 2.2$\sigma$ confidence level.
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extraction of the 235 u and 239 pu antineutrino spectra at daya bay
Physical Review Letters, 2019Co-Authors: D Adey, A B Balantekin, H R Band, M Bishai, S Blyth, G F Cao, J Cao, D Cao, J F Chang, Y ChangAbstract:This Letter reports the first extraction of individual antineutrino spectra from ^{235}U and ^{239}Pu fission and an improved measurement of the prompt energy spectrum of reactor Antineutrinos at Daya Bay. The analysis uses 3.5×10^{6} inverse beta-decay candidates in four near antineutrino detectors in 1958 days. The individual antineutrino spectra of the two dominant isotopes, ^{235}U and ^{239}Pu, are extracted using the evolution of the prompt spectrum as a function of the isotope fission fractions. In the energy window of 4-6 MeV, a 7% (9%) excess of events is observed for the ^{235}U (^{239}Pu) spectrum compared with the normalized Huber-Mueller model prediction. The significance of discrepancy is 4.0σ for ^{235}U spectral shape compared with the Huber-Mueller model prediction. The shape of the measured inverse beta-decay prompt energy spectrum disagrees with the prediction of the Huber-Mueller model at 5.3σ. In the energy range of 4-6 MeV, a maximal local discrepancy of 6.3σ is observed.
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improved measurement of the reactor antineutrino flux and spectrum at daya bay
Chinese Physics C, 2017Co-Authors: A B Balantekin, H R Band, M Bishai, S Blyth, G F Cao, J Cao, D Cao, W R Cen, Y L ChanAbstract:A new measurement of the reactor antineutrino flux and energy spectrum by the Daya Bay reactor neutrino experiment is reported. The Antineutrinos were generated by six 2.9 GWth nuclear reactors and detected by eight antineutrino detectors deployed in two near (560 m and 600 m flux-weighted baselines) and one far (1640 m flux-weighted baseline) underground experimental halls. With 621 days of data, more than 1.2 million inverse beta decay (IBD) candidates were detected. The IBD yield in the eight detectors was measured, and the ratio of measured to predicted flux was found to be 0.946±0.020 (0.992±0.021) for the Huber+Mueller (ILL+Vogel) model. A 2.9σ deviation was found in the measured IBD positron energy spectrum compared to the predictions. In particular, an excess of events in the region of 4–6 MeV was found in the measured spectrum, with a local significance of 4.4σ. A reactor antineutrino spectrum weighted by the IBD cross section is extracted for model-independent predictions.
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the detector system of the daya bay reactor neutrino experiment
Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 2016Co-Authors: F P An, A B Balantekin, H R Band, J Z Bai, D R Beavis, W Beriguete, M Bishai, S Blyth, R L BrownAbstract:The Daya Bay experiment was the first to report simultaneous measurements of reactor Antineutrinos at multiple baselines leading to the discovery of ν¯e oscillations over km-baselines. Subsequent data has provided the world׳s most precise measurement of sin^2 2θ_(13) and the effective mass splitting Δm^2_(ee). The experiment is located in Daya Bay, China where the cluster of six nuclear reactors is among the world׳s most prolific sources of electron Antineutrinos. Multiple antineutrino detectors are deployed in three underground water pools at different distances from the reactor cores to search for deviations in the antineutrino rate and energy spectrum due to neutrino mixing. Instrumented with photomultiplier tubes, the water pools serve as shielding against natural radioactivity from the surrounding rock and provide efficient muon tagging. Arrays of resistive plate chambers over the top of each pool provide additional muon detection. The antineutrino detectors were specifically designed for measurements of the antineutrino flux with minimal systematic uncertainty. Relative detector efficiencies between the near and far detectors are known to better than 0.2%. With the unblinding of the final two detectors’ baselines and target masses, a complete description and comparison of the eight antineutrino detectors can now be presented. This paper describes the Daya Bay detector systems, consisting of eight antineutrino detectors in three instrumented water pools in three underground halls, and their operation through the first year of eight detector data-taking.
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measurement of the reactor antineutrino flux and spectrum at daya bay
Physical Review Letters, 2016Co-Authors: A B Balantekin, H R Band, M Bishai, S Blyth, I. Butorov, G F Cao, J Cao, D Cao, W R Cen, Y L ChanAbstract:This Letter reports a measurement of the flux and energy spectrum of electron Antineutrinos from six 2.9 GWth nuclear reactors with six detectors deployed in two near (effective baselines 512 and 561 m) and one far (1579 m) underground experimental halls in the Daya Bay experiment. Using 217 days of data, 296 721 and 41 589 inverse β decay (IBD) candidates were detected in the near and far halls, respectively. The measured IBD yield is (1.55±0.04) ×10(-18) cm(2) GW(-1) day(-1) or (5.92±0.14) ×10(-43) cm(2) fission(-1). This flux measurement is consistent with previous short-baseline reactor antineutrino experiments and is 0.946±0.022 (0.991±0.023) relative to the flux predicted with the Huber-Mueller (ILL-Vogel) fissile antineutrino model. The measured IBD positron energy spectrum deviates from both spectral predictions by more than 2σ over the full energy range with a local significance of up to ∼4σ between 4-6 MeV. A reactor antineutrino spectrum of IBD reactions is extracted from the measured positron energy spectrum for model-independent predictions.
S Blyth - One of the best experts on this subject based on the ideXlab platform.
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extraction of the 235 u and 239 pu antineutrino spectra at daya bay
Physical Review Letters, 2019Co-Authors: D Adey, A B Balantekin, H R Band, M Bishai, S Blyth, G F Cao, J Cao, D Cao, J F Chang, Y ChangAbstract:This Letter reports the first extraction of individual antineutrino spectra from ^{235}U and ^{239}Pu fission and an improved measurement of the prompt energy spectrum of reactor Antineutrinos at Daya Bay. The analysis uses 3.5×10^{6} inverse beta-decay candidates in four near antineutrino detectors in 1958 days. The individual antineutrino spectra of the two dominant isotopes, ^{235}U and ^{239}Pu, are extracted using the evolution of the prompt spectrum as a function of the isotope fission fractions. In the energy window of 4-6 MeV, a 7% (9%) excess of events is observed for the ^{235}U (^{239}Pu) spectrum compared with the normalized Huber-Mueller model prediction. The significance of discrepancy is 4.0σ for ^{235}U spectral shape compared with the Huber-Mueller model prediction. The shape of the measured inverse beta-decay prompt energy spectrum disagrees with the prediction of the Huber-Mueller model at 5.3σ. In the energy range of 4-6 MeV, a maximal local discrepancy of 6.3σ is observed.
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improved measurement of the reactor antineutrino flux and spectrum at daya bay
Chinese Physics C, 2017Co-Authors: A B Balantekin, H R Band, M Bishai, S Blyth, G F Cao, J Cao, D Cao, W R Cen, Y L ChanAbstract:A new measurement of the reactor antineutrino flux and energy spectrum by the Daya Bay reactor neutrino experiment is reported. The Antineutrinos were generated by six 2.9 GWth nuclear reactors and detected by eight antineutrino detectors deployed in two near (560 m and 600 m flux-weighted baselines) and one far (1640 m flux-weighted baseline) underground experimental halls. With 621 days of data, more than 1.2 million inverse beta decay (IBD) candidates were detected. The IBD yield in the eight detectors was measured, and the ratio of measured to predicted flux was found to be 0.946±0.020 (0.992±0.021) for the Huber+Mueller (ILL+Vogel) model. A 2.9σ deviation was found in the measured IBD positron energy spectrum compared to the predictions. In particular, an excess of events in the region of 4–6 MeV was found in the measured spectrum, with a local significance of 4.4σ. A reactor antineutrino spectrum weighted by the IBD cross section is extracted for model-independent predictions.
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the detector system of the daya bay reactor neutrino experiment
Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 2016Co-Authors: F P An, A B Balantekin, H R Band, J Z Bai, D R Beavis, W Beriguete, M Bishai, S Blyth, R L BrownAbstract:The Daya Bay experiment was the first to report simultaneous measurements of reactor Antineutrinos at multiple baselines leading to the discovery of ν¯e oscillations over km-baselines. Subsequent data has provided the world׳s most precise measurement of sin^2 2θ_(13) and the effective mass splitting Δm^2_(ee). The experiment is located in Daya Bay, China where the cluster of six nuclear reactors is among the world׳s most prolific sources of electron Antineutrinos. Multiple antineutrino detectors are deployed in three underground water pools at different distances from the reactor cores to search for deviations in the antineutrino rate and energy spectrum due to neutrino mixing. Instrumented with photomultiplier tubes, the water pools serve as shielding against natural radioactivity from the surrounding rock and provide efficient muon tagging. Arrays of resistive plate chambers over the top of each pool provide additional muon detection. The antineutrino detectors were specifically designed for measurements of the antineutrino flux with minimal systematic uncertainty. Relative detector efficiencies between the near and far detectors are known to better than 0.2%. With the unblinding of the final two detectors’ baselines and target masses, a complete description and comparison of the eight antineutrino detectors can now be presented. This paper describes the Daya Bay detector systems, consisting of eight antineutrino detectors in three instrumented water pools in three underground halls, and their operation through the first year of eight detector data-taking.
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measurement of the reactor antineutrino flux and spectrum at daya bay
Physical Review Letters, 2016Co-Authors: A B Balantekin, H R Band, M Bishai, S Blyth, I. Butorov, G F Cao, J Cao, D Cao, W R Cen, Y L ChanAbstract:This Letter reports a measurement of the flux and energy spectrum of electron Antineutrinos from six 2.9 GWth nuclear reactors with six detectors deployed in two near (effective baselines 512 and 561 m) and one far (1579 m) underground experimental halls in the Daya Bay experiment. Using 217 days of data, 296 721 and 41 589 inverse β decay (IBD) candidates were detected in the near and far halls, respectively. The measured IBD yield is (1.55±0.04) ×10(-18) cm(2) GW(-1) day(-1) or (5.92±0.14) ×10(-43) cm(2) fission(-1). This flux measurement is consistent with previous short-baseline reactor antineutrino experiments and is 0.946±0.022 (0.991±0.023) relative to the flux predicted with the Huber-Mueller (ILL-Vogel) fissile antineutrino model. The measured IBD positron energy spectrum deviates from both spectral predictions by more than 2σ over the full energy range with a local significance of up to ∼4σ between 4-6 MeV. A reactor antineutrino spectrum of IBD reactions is extracted from the measured positron energy spectrum for model-independent predictions.
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improved measurement of electron antineutrino disappearance at daya bay
arXiv: High Energy Physics - Experiment, 2012Co-Authors: J Z Bai, A B Balantekin, H R Band, W Beriguete, M Bishai, S Blyth, R L Brown, G F Cao, J Cao, R CarrAbstract:We report an improved measurement of the neutrino mixing angle $\theta_{13}$ from the Daya Bay Reactor Neutrino Experiment. We exclude a zero value for $\sin^22\theta_{13}$ with a significance of 7.7 standard deviations. Electron Antineutrinos from six reactors of 2.9 GW$_{\rm th}$ were detected in six antineutrino detectors deployed in two near (flux-weighted baselines of 470 m and 576 m) and one far (1648 m) underground experimental halls. Using 139 days of data, 28909 (205308) electron antineutrino candidates were detected at the far hall (near halls). The ratio of the observed to the expected number of Antineutrinos assuming no oscillations at the far hall is $0.944\pm 0.007({\rm stat.}) \pm 0.003({\rm syst.})$. An analysis of the relative rates in six detectors finds $\sin^22\theta_{13}=0.089\pm 0.010({\rm stat.})\pm0.005({\rm syst.})$ in a three-neutrino framework.