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[en] This paper presents a feasibility study of the use of the detection of reactor-antineutrinos (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 "2"3"5U, "2"3"9Pu and "2"4"1Pu. 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

[en] Modern precision neutrino experiments like Double Chooz require a highly efficient trigger system in order to reduce systematic uncertainties. The trigger and timing system of the Double Chooz experiment was designed according to this goal. The Double Chooz trigger system is driven by the basic idea of triggering on multiple thresholds according to the total visible energy and additionally triggering on the number of active photomultiplier tubes (PMTs) in the detector. To do so, the trigger system continuously monitors the analogue signals from all PMTs in the detector. The amplitudes of these PMT-signals are summed for groups of certain PMTs (group signals) and for all PMTs (sum signal), respectively. The group signals are discriminated by two thresholds for each input channel and four thresholds for the sum signal. The resulting signals are processed by the trigger logic unit which is implemented in a FPGA. In addition to the proper trigger, the trigger system provides a common clock signal for all subsequent data acquisition systems to guarantee a synchronous readout of the Double Chooz detectors. The present design of the system provides a high flexibility for the applied logic and settings, making it useful for experiments other than Double Chooz. The Double Chooz trigger and timing system was installed and commissioned in 2011. This article describes the hardware of the trigger and timing system. Furthermore the setup, implemented trigger logic and performance of the trigger and timing system for the Double Chooz experiment is presented.

[en] Neutrinos are the most abundant matter particles in the Universe. Thoroughly investigated in basic science, the neutrino field is now delivering first applications for nuclear reactor monitoring. We present here the NUCIFER neutrino experiment to automatically and non-intrusively monitor nuclear power plant thermal power and Plutonium content. The core of the detector is a one ton Gadolinium-doped liquid scintillator tank to be installed in a basement room less than 30 m from a reactor core. The Division of Technical Support (SGTS) within the IAEA Department of Safeguards is currently investigating the potentiality of neutrinos as a novel safeguards tool. (author)

[en] The understanding of the antineutrino production in fission and the theoretical calculation of the antineutrino energy spectra in different, also future, types of fission reactors rely on the application of the summation method, where the individual contributions from the different radioactive nuclides that undergo a beta decay are estimated and summed up. The most accurate estimation of the independent fission-product yields is essential to this calculation. This is a complex task because the yields depend on the fissioning nucleus and on the energy spectrum of the incident neutrons. In the present contribution, the quality of different sources of information on the fission yields is investigated, and the benefit of a combined analysis is demonstrated. The influence on antineutrino predictions is discussed. In a systematic comparison, the quality of fission-product yields emerging from different experimental techniques is analyzed. The traditional radiochemical method, which is almost exclusively used for evaluations, provides an unambiguous identification in Z and A, but it is restricted to a limited number of suitable targets, is slow, and the accuracy suffers from uncertainties in the spectroscopic nuclear properties. Experiments with powerful spectrometers, for example at LOHENGRIN, provide very accurate mass yields and a Z resolution for light fission products from thermal-neutron-induced fission of a few suitable target nuclei. On the theoretical side, the general fission model GEF has been developed. It combines a few general theorems, rules and ideas with empirical knowledge. GEF covers almost all fission observables and is able to reproduce measured data with high accuracy while having remarkable predictive power by establishing and exploiting unexpected systematics and hidden regularities in the fission observables. In this article, we have coupled for the first time the GEF predictions for the fission yields to fission-product beta-decay data in a summation calculation of reactor antineutrino energy spectra. The first comparisons performed between the spectra from GEF and those obtained with the evaluated nuclear databases exhibited large discrepancies that highlighted the exigency of the modelisation of the antineutrino spectra and showing their usefulness in the evaluation of nuclear data. Additional constraints for the GEF model were thus needed in order to reach the level of accuracy required by the antineutrino energy spectra. The combination of a careful study of the independent isotopic yields and the adjunction of the LOHENGRIN fission-yield data as additional constraints led to a substantially improved agreement between the antineutrino spectra computed with GEF and with the evaluated data. The comparison of inverse beta-decay yields computed with GEF with those measured by the Daya Bay experiment shows the excellent level of predictiveness of the GEF model for the fundamental or applied antineutrino physics. The main results of this study are:–an improved agreement between the antineutrino energy spectra obtained with the newly tuned GEF model and the JEFF-3.1.1 and JEFF-3.3 fission yields for the four main contributors to fission in standard power reactors; –indications for shortcomings of mass yields for ²⁴¹Pu(n_th, f) and other systems in current evaluations; –a demonstration of the benefit from cross-checking the results of different experimental approaches and GEF for improving the quality of nuclear data; –an analysis of the sources of uncertainties and erroneous results from different experimental approaches; –the capacity of GEF for predicting the fission yields (and other observables) in cases (in terms of fissioning systems and excitation energies) which are presently not accessible to experiment; –predictions of antineutrino energy spectra that aim to assess the prospects for reactor monitoring, and based on the GEF fission yields associated with the beta-decay data of the most recent summation model.

[en] This paper attempts to summarize the actual problematic of reactor antineutrino energy spectra in the frame of fundamental and applied neutrino physics. Nuclear physics is an important ingredient of reactor antineutrino experiments. These experiments are motivated by neutrino oscillations, i.e. the measure of the θ₁₃ mixing angle. In 2011, after a new computation of the reactor antineutrino energy spectra, based on the conversion of integral data of the beta spectra from ²³⁵U, and ^239;241Pu, a deficit of reactor antineutrinos measured by short baseline experiments was pointed out. This is called the 'reactor anomaly', a new puzzle in the neutrino physics area. Since then, numerous new experimental neutrino projects have emerged. In parallel, computations of the antineutrino spectra independent from the ILL data would be desirable. One possibility is the use of the summation method, summing all the contributions of the fission product beta decay branches that can be found in nuclear databases. Studies have shown that in order to obtain reliable summation antineutrino energy spectra, new nuclear physics measurements of selected fission product beta decay properties are required. In these proceedings, we will present the computation methods of reactor antineutrino energy spectra and the impact of recent beta decay measurements on summation method spectra. The link of these nuclear physics studies with short baseline line oscillation search will be drawn and new neutrino physics projects at research reactors will be briefly presented. (authors)

[en] The aim of this work is to study the impact of the inclusion of the recently measured β decay properties of the "1"0"2","1"0"4","1"0"5","1"0"6","1"0"7Tc, "1"0"5Mo, and "1"0"1Nb nuclei in the calculation of the antineutrino (anti-ν) energy spectra arising after the fissions of the four main fissile isotopes "2"3"5","2"3"8U, and "2"3"9","2"4"1Pu in PWRs. These β feeding probabilities, measured using the Total Absorption Technique (TAS) at the JYFL facility of Jyväskylä, have been found to play a major role in the γ component of the decay heat for "2"3"9Pu in the 4-3000 s range. Following the fission product summation method, the calculation was performed using the MCNP Utility Reactor Evolution code (MURE) coupled to the experimental spectra built from β decay properties of the fission products taken from evaluated databases. These latest TAS data are found to have a significant effect on the Pu isotope energy spectra and on the spectrum of "2"3"8U showing the importance of their measurement for a better assessment of the reactor anti-ν energy spectrum, as well as importance for fundamental neutrino physics experiments and neutrino applied physics

[en] In this work we report on the Monte Carlo study performed to understand and reproduce experimental measurements of a new plastic β-detector with cylindrical geometry. Since energy deposition simulations differ from the experimental measurements for such a geometry, we show how the simulation of production and transport of optical photons does allow one to obtain the shapes of the experimental spectra. Moreover, taking into account the computational effort associated with this kind of simulation, we develop a method to convert the simulations of energy deposited into light collected, depending only on the interaction point in the detector. This method represents a useful solution when extensive simulations have to be done, as in the case of the calculation of the response function of the spectrometer in a total absorption γ-ray spectroscopy analysis.

[en] Three observables of interest for present and future reactors depend on the beta 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 Total Absorption Gamma-ray Spectroscopy (TAGS) results from the latest experiment of the TAGS collaboration at the JYFL facility of Jyvaeskylae will be displayed as well as their impact on the antineutrino spectra and the decay heat associated to fission pulses of the main actinides. (authors)

[en] We present a search for Lorentz violation with 8249 candidate electron antineutrino events taken by the Double Chooz experiment in 227.9 live days of running. This analysis, featuring a search for a sidereal time dependence of the events, is the first test of Lorentz invariance using a reactor-based antineutrino source. No sidereal variation is present in the data and the disappearance results are consistent with sidereal time independent oscillations. Under the Standard-Model Extension, we set the first limits on 14 Lorentz violating coefficients associated with transitions between electron and tau flavor, and set two competitive limits associated with transitions between electron and muon flavor. (authors)