The Experts below are selected from a list of 14277 Experts worldwide ranked by ideXlab platform
H R Band - One of the best experts on this subject based on the ideXlab platform.
-
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.
-
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.
-
The PROSPECT Reactor Antineutrino Experiment
Nuclear Instruments and Methods in Physics Research Section A: Accelerators Spectrometers Detectors and Associated Equipment, 2019Co-Authors: J. Ashenfelter, N S Bowden, A B Balantekin, H R Band, C D Bass, Denis E Bergeron, D Berish, C. Baldenegro, L. J. Bignell, J. BoyleAbstract:Abstract The Precision Reactor Oscillation and Spectrum Experiment, PROSPECT, is designed to make both a precise measurement of the Antineutrino spectrum from a highly-enriched uranium reactor and to probe eV-scale sterile neutrinos by searching for neutrino oscillations over meter-long baselines. PROSPECT utilizes a segmented 6 Li-doped liquid scintillator detector for both efficient detection of reactor Antineutrinos through the inverse beta decay reaction and excellent background discrimination. PROSPECT is a movable 4-ton Antineutrino detector covering distances of 7 m to 13 m from the High Flux Isotope Reactor core. It will probe the best-fit point of the ν e disappearance experiments at 4 σ in 1 year and the favored regions of the sterile neutrino parameter space at more than 3 σ in 3 years. PROSPECT will test the origin of spectral deviations observed in recent θ 13 experiments, search for sterile neutrinos, and address the hypothesis of sterile neutrinos as an explanation of the reactor anomaly. This paper describes the design, construction, and commissioning of PROSPECT and reports first data characterizing the performance of the PROSPECT Antineutrino detector.
-
first search for short baseline neutrino oscillations at hfir with prospect
Physical Review Letters, 2018Co-Authors: J. Ashenfelter, N S Bowden, A B Balantekin, H R Band, C D Bass, Denis E Bergeron, D Berish, C. Baldenegro, L. J. Bignell, J BriccoAbstract:: This Letter reports the first scientific results from the observation of Antineutrinos emitted by fission products of ^{235}U at the High Flux Isotope Reactor. PROSPECT, the Precision Reactor Oscillation and Spectrum Experiment, consists of a segmented 4 ton ^{6}Li-doped liquid scintillator detector covering a baseline range of 7-9 m from the reactor and operating under less than 1 m water equivalent overburden. Data collected during 33 live days of reactor operation at a nominal power of 85 MW yield a detection of 25 461±283 (stat) inverse beta decays. Observation of reactor Antineutrinos can be achieved in PROSPECT at 5σ statistical significance within 2 h of on-surface reactor-on data taking. A reactor model independent analysis of the inverse beta decay prompt energy spectrum as a function of baseline constrains significant portions of the previously allowed sterile neutrino oscillation parameter space at 95% confidence level and disfavors the best fit of the reactor Antineutrino anomaly at 2.2σ confidence level.
-
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.
A B Balantekin - One of the best experts on this subject based on the ideXlab platform.
-
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.
-
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.
-
The PROSPECT Reactor Antineutrino Experiment
Nuclear Instruments and Methods in Physics Research Section A: Accelerators Spectrometers Detectors and Associated Equipment, 2019Co-Authors: J. Ashenfelter, N S Bowden, A B Balantekin, H R Band, C D Bass, Denis E Bergeron, D Berish, C. Baldenegro, L. J. Bignell, J. BoyleAbstract:Abstract The Precision Reactor Oscillation and Spectrum Experiment, PROSPECT, is designed to make both a precise measurement of the Antineutrino spectrum from a highly-enriched uranium reactor and to probe eV-scale sterile neutrinos by searching for neutrino oscillations over meter-long baselines. PROSPECT utilizes a segmented 6 Li-doped liquid scintillator detector for both efficient detection of reactor Antineutrinos through the inverse beta decay reaction and excellent background discrimination. PROSPECT is a movable 4-ton Antineutrino detector covering distances of 7 m to 13 m from the High Flux Isotope Reactor core. It will probe the best-fit point of the ν e disappearance experiments at 4 σ in 1 year and the favored regions of the sterile neutrino parameter space at more than 3 σ in 3 years. PROSPECT will test the origin of spectral deviations observed in recent θ 13 experiments, search for sterile neutrinos, and address the hypothesis of sterile neutrinos as an explanation of the reactor anomaly. This paper describes the design, construction, and commissioning of PROSPECT and reports first data characterizing the performance of the PROSPECT Antineutrino detector.
-
first search for short baseline neutrino oscillations at hfir with prospect
Physical Review Letters, 2018Co-Authors: J. Ashenfelter, N S Bowden, A B Balantekin, H R Band, C D Bass, Denis E Bergeron, D Berish, C. Baldenegro, L. J. Bignell, J BriccoAbstract:: This Letter reports the first scientific results from the observation of Antineutrinos emitted by fission products of ^{235}U at the High Flux Isotope Reactor. PROSPECT, the Precision Reactor Oscillation and Spectrum Experiment, consists of a segmented 4 ton ^{6}Li-doped liquid scintillator detector covering a baseline range of 7-9 m from the reactor and operating under less than 1 m water equivalent overburden. Data collected during 33 live days of reactor operation at a nominal power of 85 MW yield a detection of 25 461±283 (stat) inverse beta decays. Observation of reactor Antineutrinos can be achieved in PROSPECT at 5σ statistical significance within 2 h of on-surface reactor-on data taking. A reactor model independent analysis of the inverse beta decay prompt energy spectrum as a function of baseline constrains significant portions of the previously allowed sterile neutrino oscillation parameter space at 95% confidence level and disfavors the best fit of the reactor Antineutrino anomaly at 2.2σ confidence level.
-
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.
Muriel Fallot - One of the best experts on this subject based on the ideXlab platform.
-
summation calculations for reactor Antineutrino spectra decay heat and delayed neutron fractions involving new tags data and evaluated databases
European Physical Journal Web of Conferences, 2019Co-Authors: M Estienne, Muriel Fallot, Lydie Giot, V Guadillagomez, Le L Meur, A Porta, A Algora, J L Tain, Jose Antonio BrizAbstract:Three observables of interest for present and future reactors depend on the β decay properties of the fission products: Antineutrinos from reactors, the reactor decay heat and delayed neutron emission. In these proceedings, we present new results from summation calculations of the first two quantities quoted above, performed with evolved independent yields coupled with fission product decay data, from various nuclear data bases or models. New TAGS results from the latest experiment of the TAGS collaboration at the JYFL facility of Jyvaskyla will be displayed as well as their impact on the Antineutrino spectra and the decay heat associated to fission pulses of the main actinides.
-
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.
-
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.
-
Reactor Simulation for Antineutrino Experiments using DRAGON and MURE
Physical Review D, 2012Co-Authors: C. L. Jones, Muriel Fallot, Lydie Giot, A Bernstein, J.m. Conrad, G. Keefer, A. Onillon, Z. Djurcic, L. WinslowAbstract:Rising interest in nuclear reactors as a source of Antineutrinos for experiments motivates validated, fast, and accessible simulations to predict reactor fission rates. Here we present results from the DRAGON and MURE simulation codes and compare them to other industry standards for reactor core modeling. We use published data from the Takahama-3 reactor to evaluate the quality of these simulations against the independently measured fuel isotopic composition. The propagation of the uncertainty in the reactor operating parameters to the resulting Antineutrino flux predictions is also discussed.
-
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.
A Bernstein - One of the best experts on this subject based on the ideXlab platform.
-
sensitivity of seismically cued Antineutrino detectors to nuclear explosions
Physical review applied, 2018Co-Authors: R Carr, Ferenc Dalnokiveress, A BernsteinAbstract:Could Antineutrinos help to verify compliance with a ban on nuclear weapons testing, or provide useful information about illicit tests? Surprisingly, detectors proposed for basic physics may be capable of detecting Antineutrinos from faraway nuclear tests. Seismic data is key to the analysis. This study explores how large, water-based Antineutrino detectors could rapidly confirm the nuclear nature of an explosion, constrain estimates of the fission yield, and provide other forensic insight.
-
sensitivity of seismically cued Antineutrino detectors to nuclear explosions
arXiv: Nuclear Experiment, 2017Co-Authors: R Carr, Ferenc Dalnokiveress, A BernsteinAbstract:We evaluate the sensitivity of large, gadolinium-doped water detectors to Antineutrinos released by nuclear fission explosions, using updated signal and background models and taking advantage of the capacity for seismic observations to provide an analysis trigger. Under certain realistic conditions, the Antineutrino signature of a 250-kiloton pure fission explosion could be identified several hundred kilometers away in a detector about the size of the largest module currently proposed for a basic physics experiment. In principle, such an observation could provide rapid confirmation that the seismic signal coincided with a fission event, possibly useful for international monitoring of nuclear weapon tests. We discuss the limited potential for seismically cued Antineutrino observations to constrain fission yield, differentiate pure fission from fusion-enhanced weapon tests, indicate that the seismic evidence of an explosion had been intentionally masked, or verify the absence of explosive testing in a targeted area. We conclude that advances in seismic monitoring and neutrino physics have made the detection of explosion-derived Antineutrinos more conceivable than previously asserted, but the size and cost of sufficiently sensitive detectors continue to limit applications.
-
reactors as a source of Antineutrinos the effect of fuel loading and burnup for mixed oxide fuels
arXiv: Nuclear Experiment, 2016Co-Authors: A Bernstein, N S Bowden, Anna EricksonAbstract:In a conventional light water reactor loaded with a range of uranium and plutonium-based fuel mixtures, the variation in Antineutrino production over the cycle reflects both the initial core fissile inventory and its evolution. Under the assumption of constant thermal power, we calculate the rate at which Antineutrinos are emitted from variously fueled cores, and the evolution of that rate as measured by a representative ton-scale Antineutrino detector. We find that Antineutrino flux decreases with burnup for Low Enriched Uranium cores, increases for full mixed-oxide (MOX) cores, and does not appreciably change for cores with a MOX fraction of approximately 75%. Accounting for uncertainties in the fission yields, in the emitted Antineutrino spectra, and the detector response function, we show that the difference in core-wide MOX fractions at least as small as 8% can be distinguished using a hypothesis test. The test compares the evolution of the Antineutrino rate relative to an initial value over part or all of the cycle. The use of relative rates reduces the sensitivity of the test to an independent thermal power measurement, making the result more robust against possible countermeasures. This rate-only approach also offers the potential advantage of reducing the cost and complexity of the Antineutrino detectors used to verify the diversion, compared to methods that depend on the use of the Antineutrino spectrum. A possible application is the verification of the disposition of surplus plutonium in nuclear reactors.
-
Antineutrino monitoring of thorium reactors
arXiv: Instrumentation and Detectors, 2015Co-Authors: Oluwatomi A. Akindele, A Bernstein, Eric B. NormanAbstract:Various groups have demonstrated that Antineutrino monitoring can be successful in assessing the plutonium content in water-cooled nuclear reactors for nonproliferation applications. New reactor designs and concepts incorporate nontraditional fuels types and chemistry. Understanding how these properties affect the Antineutrino emission from a reactor can extend the applicability of Antineutrino monitoring. Thorium molten salt reactors (MSR) breed U-233, that if diverted constitute a direct use material as defined by the International Atomic Energy Agency (IAEA). The Antineutrino spectrum from the fission of U-233 has been estimated for the first time, and the feasibility of detecting the diversion of 8 kg of U-233, within a 30 day timeliness goal has been evaluated. The Antineutrino emission from a thorium reactor operating under normal conditions is compared to a diversion scenario by evaluating the daily Antineutrino count rate and the energy spectrum of the detected Antineutrinos at a 25 meter standoff. It was found that the diversion of a significant quantity of U-233 could not be detected within the current IAEA timeliness detection goal using either tests. A rate-time based analysis exceeded the timeliness goal by 23 days, while a spectral based analysis exceeds this goal by 31 days.
-
Reactor Simulation for Antineutrino Experiments using DRAGON and MURE
Physical Review D, 2012Co-Authors: C. L. Jones, Muriel Fallot, Lydie Giot, A Bernstein, J.m. Conrad, G. Keefer, A. Onillon, Z. Djurcic, L. WinslowAbstract:Rising interest in nuclear reactors as a source of Antineutrinos for experiments motivates validated, fast, and accessible simulations to predict reactor fission rates. Here we present results from the DRAGON and MURE simulation codes and compare them to other industry standards for reactor core modeling. We use published data from the Takahama-3 reactor to evaluate the quality of these simulations against the independently measured fuel isotopic composition. The propagation of the uncertainty in the reactor operating parameters to the resulting Antineutrino flux predictions is also discussed.
M Bishai - One of the best experts on this subject based on the ideXlab platform.
-
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.
-
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.
-
search for time independent lorentz violation using muon neutrino to muon Antineutrino transitions in minos
arXiv: High Energy Physics - Experiment, 2016Co-Authors: P Adamson, M Bishai, I Anghel, A Aurisano, G Barr, A Blake, G J Bock, D Bogert, S Cao, T J CarrollAbstract:Data from the MINOS experiment has been used to search for mixing between muon neutrinos and muon Antineutrinos using a time-independent Lorentz-violating formalism derived from the Standard-Model Extension (SME). MINOS is uniquely capable of searching for muon neutrino-Antineutrino mixing given its long baseline and ability to distinguish between neutrinos and Antineutrinos on an event-by-event basis. Neutrino and Antineutrino interactions were observed in the MINOS Near and Far Detectors from an exposure of 10.56$\times10^{20}$ protons-on-target from the NuMI neutrino-optimized beam. No evidence was found for such transitions and new, highly stringent limits were placed on the SME coefficients governing them. We place the first limits on the SME parameters $(c_{L})^{TT}_{\mu\mu} $ and $(c_{L})^{TT}_{\tau\tau}$ at $-8.4\times10^{-23} < (c_{L})^{TT}_{\mu\mu} < 8.0\times10^{-23}$ and $-8.0\times10^{-23} < (c_{L})^{TT}_{\tau\tau} < 8.4\times10^{-23}$, and the world's best limits on the $\tilde{g}^{ZT}_{\mu\overline{\mu}}$ and $\tilde{g}^{ZT}_{\tau\overline{\tau}}$ parameters at $|\tilde{g}^{ZT}_{\mu\overline{\mu}}| < 3.3\times 10^{-23}$ and $|\tilde{g}^{ZT}_{\tau\overline{\tau}}| < 3.3\times 10^{-23}$, all limits quoted at $3\sigma$.
-
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.
-
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.
