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Reactor Simulation for Antineutrino Experiments using DRAGON and MURE  [PDF]
C. L. Jones,A. Bernstein,J. M. Conrad,Z. Djurcic,M. Fallot,L. Giot,G. Keefer,A. Onillon,L. Winslow
Physics , 2011, DOI: 10.1103/PhysRevD.86.012001
Abstract: 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.
Simulation of Reactors for Antineutrino Experiments Using DRAGON  [PDF]
L. Winslow
Physics , 2011,
Abstract: From the discovery of the neutrino to the precision neutrino oscillation measurements in KamLAND, nuclear reactors have proven to be an important source of antineutrinos. As their power and our knowledge of neutrino physics has increased, more sensitive measurements have become possible. The next generation of reactor antineutrino experiments require more detailed simulations of the reactor core. Many of the reactor simulation codes are proprietary which makes detailed studies difficult. Here we present the results of the open source DRAGON code and compare it to other industry standards for reactor modeling. We use published data from the Takahama reactor to determine the quality of the simulations. The propagation of the uncertainty to the antineutrino flux is also discussed.
Uncertainties analysis of fission fraction for reactor antineutrino experiments  [PDF]
X. B. Ma,F. Lu,L. Z. Wang,Y. X. Chen,W. L. Zhong,F. P. An
Physics , 2014,
Abstract: Reactor antineutrino experiment are used to study neutrino oscillation, search for signatures of nonstandard neutrino interaction, and monitor reactor operation for safeguard application. Reactor simulation is an important source of uncertainties for a reactor neutrino experiment. Commercial code is used for reactor simulation to evaluate fission fraction in Daya Bay neutrino experiment, but the source code doesn't open to our researcher results from commercial secret. In this study, The open source code DRAGON was improved to calculate the fission rates of the four most important isotopes in fissions, $^{235}$U,$^{238}$U,$^{239}$Pu and $^{241}$Pu, and then was validated for PWRs using the Takahama-3 benchmark. The fission fraction results are consistent with those of MIT's results. Then, fission fraction of Daya Bay reactor core was calculated by using improved DRAGON code, and the fission fraction calculated by DRAGON agreed well with these calculated by SCIENCE. The average deviation less than 5\% for all the four isotopes. The correlation coefficient matrix between $^{235}$U,$^{238}$U,$^{239}$Pu and $^{241}$Pu were also studied using DRAGON, and then the uncertainty of the antineutrino flux by the fission fraction was calculated by using the correlation coefficient matrix. The uncertainty of the antineutrino flux by the fission fraction simulation is 0.6\% per core for Daya Bay antineutrino experiment. The uncertainties source of fission fraction calculation need further to be studied in the future.
Antineutrino flux from the Laguna Verde Nuclear Power Plant  [PDF]
Marisol Chavez-Estrada,Alexis A. Aguilar-Arevalo
Physics , 2015, DOI: 10.1155/2015/109738
Abstract: We present a calculation of the antineutrino flux produced by the reactors at the Laguna Verde Nuclear Power Plant in M\'exico, based on the antineutrino spectra produced in the decay chains of the fission fragments of the main isotopes in the reactor core, and their fission rates, that have been calculated using the DRAGON simulation code. We also present an estimate of the number of expected events in a detector made of plastic scintillator with a mass of 1 ton, at 100 m from the reactor cores.
Measurement of the Reactor Antineutrino Flux and Spectrum at Daya Bay  [PDF]
Daya Bay Collaboration,F. P. An,A. B. Balantekin,H. R. Band,M. Bishai,S. Blyth,I. Butorov,D. Cao,G. F. Cao,J. Cao,W. R. Cen,Y. L. Chan,J. F. Chang,L. C. Chang,Y. Chang,H. S. Chen,Q. Y. Chen,S. M. Chen,Y. X. Chen,Y. Chen,J. H. Cheng,J. Cheng,Y. P. Cheng,J. J. Cherwinka,M. C. Chu,J. P. Cummings,J. de Arcos,Z. Y. Deng,X. F. Ding,Y. Y. Ding,M. V. Diwan,J. Dove,E. Draeger,D. A. Dwyer,W. R. Edwards,S. R. Ely,R. Gill,M. Gonchar,G. H. Gong,H. Gong,M. Grassi,W. Q. Gu,M. Y. Guan,L. Guo,X. H. Guo,R. W. Hackenburg,R. Han,S. Hans,M. He,K. M. Heeger,Y. K. Heng,A. Higuera,Y. K. Hor,Y. B. Hsiung,B. Z. Hu,L. M. Hu,L. J. Hu,T. Hu,W. Hu,E. C. Huang,H. X. Huang,X. T. Huang,P. Huber,G. Hussain,D. E. Jaffe,P. Jaffke,K. L. Jen,S. Jetter,X. P. Ji,X. L. Ji,J. B. Jiao,R. A. Johnson,L. Kang,S. H. Kettell,S. Kohn,M. Kramer,K. K. Kwan,M. W. Kwok,T. Kwok,T. J. Langford,K. Lau,L. Lebanowski,J. Lee,R. T. Lei,R. Leitner,K. Y. Leung,J. K. C. Leung,C. A. Lewis,D. J. Li,F. Li,G. S. Li,Q. J. Li,S. C. Li,W. D. Li,X. N. Li,X. Q. Li,Y. F. Li,Z. B. Li,H. Liang,C. J. Lin,G. L. Lin,P. Y. Lin,S. K. Lin,J. J. Ling,J. M. Link,L. Littenberg,B. R. Littlejohn,D. W. Liu,H. Liu,J. L. Liu,J. C. Liu,S. S. Liu,C. Lu,H. Q. Lu,J. S. Lu,K. B. Luk,Q. M. Ma,X. Y. Ma,X. B. Ma,Y. Q. Ma,D. A. Martinez Caicedo,K. T. McDonald,R. D. McKeown,Y. Meng,I. Mitchell,J. Monari Kebwaro,Y. Nakajima,J. Napolitano,D. Naumov,E. Naumova,H. Y. Ngai,Z. Ning,J. P. Ochoa-Ricoux,A. Olshevski,H. -R. Pan,J. Park,S. Patton,V. Pec,J. C. Peng,L. E. Piilonen
Physics , 2015,
Abstract: This Letter reports a measurement of the flux and energy spectrum of electron antineutrinos from six 2.9~GW$_{th}$ nuclear reactors with six detectors deployed in two near (effective baselines 512~m and 561~m) and one far (1,579~m) underground experimental halls in the Daya Bay experiment. Using 217 days of data, 296,721 and 41,589 inverse beta decay (IBD) candidates were detected in the near and far halls, respectively. The measured IBD yield is (1.55 $\pm$ 0.04) $\times$ 10$^{-18}$~cm$^2$/GW/day or (5.92 $\pm$ 0.14) $\times$ 10$^{-43}$~cm$^2$/fission. This flux measurement is consistent with previous short-baseline reactor antineutrino experiments and is $0.946\pm0.022$ ($0.991\pm0.023$) 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 2$\sigma$ over the full energy range with a local significance of up to $\sim$4$\sigma$ between 4-6 MeV. A reactor antineutrino spectrum of IBD reactions is extracted from the measured positron energy spectrum for model-independent predictions.
An estimate of theta_14 independent of the reactor antineutrino flux determinations  [PDF]
Antonio Palazzo
Physics , 2012, DOI: 10.1103/PhysRevD.85.077301
Abstract: In a previous paper [Phys. Rev. D 83, 113013 (2011)] we have shown that the solar sector data (solar and KamLAND) are sensitive to the parameter theta_14, encoding the admixture of the electron neutrino with a fourth (essentially) sterile mass eigenstate. In that work we evidenced that such data prefer a non-zero value of theta_14 and that such a preference is completely degenerate with that of non-zero theta_13. In this report we show how the evidence of theta_13 > 0, recently emerged from global neutrino data analyses, lifts such a degeneracy and disfavors the case of sterile neutrino mixing. By excluding from our analysis the total rate information coming from the reactor experiments we untie our results from any assumption on their flux normalization. In this way, we establish the robust upper bound sin^2 (theta_14) < 0.04 at the 90% C.L.
Inverse Beta Decay in a Nonequilibrium Antineutrino Flux from a Nuclear Reactor  [PDF]
V. I. Kopeikin,L. A. Mikaelyan,V. V. Sinev
Physics , 2001, DOI: 10.1134/1.1378874
Abstract: The evolution of the reactor antineutrino spectrum toward equilibrium above the inverse beta-decay threshold during the reactor operating period and the decay of residual antineutrino radiation after reactor shutdown are considered. It is found that, under certain conditions, these processes can play a significant role in experiments seeking neutrino oscillations.
On Search for New Physics in Nonequilibrium Reactor Antineutrino Energy Spectrum  [PDF]
V. I. Kopeikin
Physics , 2001, DOI: 10.1134/1.1563708
Abstract: The calculations of the time-dependent reactor antineutrino energy spectrum are presented. Some problems associated with sensitive searches for neutrino magnetic moment and neutrino oscillations in reactor antineutrino flux are considered.
Reactor Antineutrino Anomaly with known θ_{13}  [PDF]
C. Zhang,X. Qian,P. Vogel
Physics , 2013, DOI: 10.1103/PhysRevD.87.073018
Abstract: We revisit the reactor antineutrino anomaly using the recent reactor flux independent determination of sizable theta?13 by considering the full set of the absolute reactor electron antineutrino flux measurements. When normalized to the predicted flux of Mueller et al. [1], the new world average, after including results from Palo Verde, Chooz, and Double Chooz, is 0.959 +- 0.009 (experiment uncertainty) +- 0.027 (flux systematics). Including the data with kilometer baseline, the new world average is only about 1.4 sigma lower than the unity, weakening the significance of the reactor antineutrino anomaly. The upcoming results from Daya Bay, RENO, and the Double Chooz will provide further information about this issue.
The Reactor Antineutrino Anomaly  [PDF]
G. Mention,M. Fechner,Th. Lasserre,Th. A. Mueller,D. Lhuillier,M. Cribier,A. Letourneau
Physics , 2011, DOI: 10.1103/PhysRevD.83.073006
Abstract: Recently new reactor antineutrino spectra have been provided for 235U, 239Pu, 241Pu and 238U, increasing the mean flux by about 3 percent. To good approximation, this reevaluation applies to all reactor neutrino experiments. The synthesis of published experiments at reactor-detector distances <100 m leads to a ratio of observed event rate to predicted rate of 0.976(0.024). With our new flux evaluation, this ratio shifts to 0.943(0.023), leading to a deviation from unity at 98.6% C.L. which we call the reactor antineutrino anomaly. The compatibility of our results with the existence of a fourth non-standard neutrino state driving neutrino oscillations at short distances is discussed. The combined analysis of reactor data, gallium solar neutrino calibration experiments, and MiniBooNE-neutrino data disfavors the no-oscillation hypothesis at 99.8% C.L. The oscillation parameters are such that |Delta m_{new}^2|>1.5 eV^2 (95%) and sin^2(2\theta_{new})=0.14(0.08) (95%). Constraints on the theta13 neutrino mixing angle are revised.
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