47 research outputs found

    Reactor Neutrino Flux Uncertainty Suppression on Multiple Detector Experiments

    Full text link
    This publication provides a coherent treatment for the reactor neutrino flux uncertainties suppression, specially focussed on the latest θ13\theta_{13} measurement. The treatment starts with single detector in single reactor site, most relevant for all reactor experiments beyond θ13\theta_{13}. We demonstrate there is no trivial error cancellation, thus the flux systematic error can remain dominant even after the adoption of multi-detector configurations. However, three mechanisms for flux error suppression have been identified and calculated in the context of Double Chooz, Daya Bay and RENO sites. Our analysis computes the error {\it suppression fraction} using simplified scenarios to maximise relative comparison among experiments. We have validated the only mechanism exploited so far by experiments to improve the precision of the published θ13\theta_{13}. The other two newly identified mechanisms could lead to total error flux cancellation under specific conditions and are expected to have major implications on the global θ13\theta_{13} knowledge today. First, Double Chooz, in its final configuration, is the only experiment benefiting from a negligible reactor flux error due to a ∼\sim90\% geometrical suppression. Second, Daya Bay and RENO could benefit from their partial geometrical cancellation, yielding a potential ∼\sim50\% error suppression, thus significantly improving the global θ13\theta_{13} precision today. And third, we illustrate the rationale behind further error suppression upon the exploitation of the inter-reactor error correlations, so far neglected. So, our publication is a key step forward in the context of high precision neutrino reactor experiments providing insight on the suppression of their intrinsic flux error uncertainty, thus affecting past and current experimental results, as well as the design of future experiments

    Acoustic characterization of combustion chambers in reciprocating engines: An application for low knocking cycles recognition

    Full text link
    This is the author¿s version of a work that was accepted for publication in International Journal of Engine Research. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published as https://doi.org/10.1177/1468087420980565[EN] In this paper the acoustic response of a combustion chamber is studied by assuming different pressure field excitation. The viscous effects on the combustion chamber and the finite impedance of the walls have been modeled with a first order system, which damps the resonance oscillation created by combustion. The characterization of the acoustic response of the combustion chamber has been used to identify the source of the excitation in order to distinguish normal combustion from knock. Two engines, a conventional spark ignited (SI) and a turbulent jet ignition (TJI) engine, were used, fueled with gasoline and compressed natural gas (CNG), respectively. The pressure fluctuations in the combustion chambers are analyzed and a pattern recognition system identifies the most likely source of excitation. This new criteria for knock identification permits a more consistent differentiation between knocking and no-knocking cycles, independent on the amplitude of the phenomenon, thus allowing the improvement for knock control algorithms, specially with combustion modes which heavily excite resonance, such as turbulent jet ignition or homogeneous charge compression ignition (HCCI).The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: Irina A. Jimenez received a funding through the grant 132GRISOLIAP/2018/132 from the Generalitat Valenciana and the European Social Fund.Novella Rosa, R.; Pla Moreno, B.; Bares-Moreno, P.; Jimenez, IA. (2022). Acoustic characterization of combustion chambers in reciprocating engines: An application for low knocking cycles recognition. International Journal of Engine Research. 23(1):120-131. https://doi.org/10.1177/146808742098056512013123

    Comprehensive modeling study analyzing the insights of the NO NO2 conversion process in current diesel engines

    Full text link
    Multiple researches have focused on reducing the NOx emissions and the greatest results have been achieved when lowering the combustion temperature by employing massive exhaust gas recirculation rates (LTC). Despite this benefit, a substantial increase in the NO2 contribution to the NOx emissions has also been observed, which is the most harmful specie and is important for the design and positioning of the after-treatment devices. To understand how NO2 behaves and how it contributes to the total NOx (NO2/NOx), not only under LTC but also for CDC conditions, a stepwise computational research study was performed with Chemkin Pro software, due to the complexity of isolating the different phenomena studied, to analyze: (1) general equilibrium conditions and (2) the influence of typical diesel engine phenomena (combustion and cooling effects) under non-equilibrium conditions. The results obtained under equilibrium state confirm the theoretical guidelines established for the NO2 formation process. When considering a combustion process (HCCI-like mode), the previous results were corroborated as well as the fact that only poor or slow combustion processes are responsible for the NO2 formation. Additionally, it reflected a cyclic process between NO and NO2, or in other words, it is suffice to just concentrate on NO to be able to predict NO2. Finally, the results yield after analyzing some cooling effects, inherent to how diesel engines work (the expansion stroke, dilution of combustion products with the rest of in-cylinder charge and the one caused by wall impingement), reflect that: (1) the dilution effect explains the 10% of the NO2/NOx ratio under CDC conditions and (2) the coupling of the dilution with the expansion stroke cooling effects can explain the NO2 increase typical of LTC conditions. These results were also supported by some experiments performed in a single-cylinder diesel engine. Consequently, the cooling effect caused by dilution should be considered when modeling the NO2 formation just like the expansion stroke.The authors would like to acknowledge the contribution of the Spanish Ministry of Economic and Competitively for the financial support of the present research study associate to the Projects TRA 2008-06448 (VELOSOOT) and TRA 2010-20271 (LOWTECOM). Additionally, special acknowledgement to Dr. L. Pickett which kindly shared a copy of the TSL model to perform the diesel spray simulations.Benajes Calvo, JV.; López Sánchez, JJ.; Novella Rosa, R.; Redón Lurbe, P. (2014). Comprehensive modeling study analyzing the insights of the NO NO2 conversion process in current diesel engines. Energy Conversion and Management. 84:691-700. https://doi.org/10.1016/j.enconman.2014.04.073S6917008

    Radon Mitigation Applications at the Laboratorio Subterraneo de Canfranc (LSC)

    Get PDF
    The Laboratorio Subterraneo de Canfranc (LSC) is the Spanish national hub for low radioactivity techniques and the associated scientific and technological applications. The concentration of the airborne radon is a major component of the radioactive budget in the neighborhood of the detectors. The LSC hosts a Radon Abatement System, which delivers a radon suppressed air with 1.1 & PLUSMN;0.2 mBq/m(3) of Rn-222. The radon content in the air is continuously monitored with an Electrostatic Radon Monitor. Measurements with the double beta decay demonstrators NEXT-NEW and CROSS and the gamma HPGe detectors show the important reduction of the radioactive background due to the purified air in the vicinity of the detectors. We also discuss the use of this facility in the LSC current program which includes NEXT-100, low background biology experiments and radiopure copper electroformation equipment placed in the radon-free clean room

    Measurement of the 136Xe two-neutrino double- β -decay half-life via direct background subtraction in NEXT

    Get PDF
    NEXT Collaboration: et al.We report a measurement of the half-life of the 136Xe two-neutrino double-β decay performed with a novel direct-background-subtraction technique. The analysis relies on the data collected with the NEXT-White detector operated with 136Xe-enriched and 136Xe-depleted xenon, as well as on the topology of double-electron tracks. With a fiducial mass of only 3.5 kg of Xe, a half-life of 2.34+0.80−0.46(stat)+0.30−0.17(sys)×1021yr is derived from the background-subtracted energy spectrum. The presented technique demonstrates the feasibility of unique background-model-independent neutrinoless double-β-decay searches.The NEXT Collaboration acknowledges support from the following agencies and institutions: the European Research Council (ERC) under Grant No.951281-BOLD; the European Union’s Framework Programme for Research and Innovation Horizon 2020 (2014–2020) under Grant No. 957202-HIDDEN; the MCIN/AEI/10.13039/501100011033 of Spain and ERDF “Away of making Europe” under Grant No.RTI2018-095979, the Severo Ochoa Program Grant No.CEX2018-000867-S, and the María de Maeztu Program Grant No.MDM-2016-0692; the Generalitat Valenciana of Spain under Grants No. PROMETEO/2021/087 and No. CIDEGENT/2019/049; the Portuguese FCT under Project No. UID/FIS/04559/2020 to fund the activities of LIB Phys-UC; the Pazy Foundation (Israel) under Grants No.877040 and No.877041; the U.S. Department of Energy under Contracts No.DE-AC02-06CH11357(Argonne National Laboratory),No. DE-AC02-07CH11359 (Fermi National Accelerator Laboratory), No. DE-FG02-13ER42020 (TexasA&M),No.DE-SC0019054 (Texas Arlington), and No.DE-SC0019223 (Arlington,TX); the U.S. National Science Foundation under Grant No. CHE2004111;and the Robert A. Welch Foundation under Grant No.Y-203120200401. D.G.D. acknowledges support from the Ramón y Cajal program (Spain) under Contract No. RYC-2015-18820.Peer reviewe

    The dynamics of ions on phased radio-frequency carpets in high pressure gases and application for barium tagging in xenon gas time projection chambers

    Get PDF
    NEXT Collaboration: et al.Radio-frequency (RF) carpets with ultra-fine pitches are examined for ion transport in gases at atmospheric pressures and above. We develop new analytic and computational methods for modeling RF ion transport at densities where dynamics are strongly influenced by buffer gas collisions. An analytic description of levitating and sweeping forces from phased arrays is obtained, then thermodynamic and kinetic principles are used to calculate ion loss rates in the presence of collisions. This methodology is validated against detailed microscopic SIMION simulations. We then explore a parameter space of special interest for neutrinoless double beta decay experiments: transport of barium ions in xenon at pressures from 1 to 10 bar. Our computations account for molecular ion formation and pressure dependent mobility as well as finite temperature effects. We discuss the challenges associated with achieving suitable operating conditions, which lie beyond the capabilities of existing devices, using presently available or near-future manufacturing techniques.The University of Texas at Arlington NEXT group is supported by the Department of Energy, USA under Early Career Award number DE-SC0019054 (BJPJ), by Department of Energy, USA Award DE-SC0019223 (DRN), the National Science Foundation, USA under award number NSF CHE 2004111 (FWF), and the Robert A Welch Foundation, Y-2031-20200401 (FWF). The NEXT Collaboration acknowledges support from the following agencies and institutions: the European Research Council (ERC) under the Advanced Grant 339787-NEXT; the European Union’s Framework Programme for Research and Innovation Horizon 2020 (2014–2020) under the Grant Agreements No. 674896, 690575 and 740055; the Ministerio de Economía Competitividad and the Ministerio de Ciencia, Innovación Universidades of Spain under grants FIS2014-53371-C04, RTI2018-095979, the Severo Ochoa Program grants SEV-2014-0398 and CEX2018-000867-S, and the María de Maeztu Program MDM-2016-0692; from Fundacion Bancaria la Caixa (ID 100010434), grant code LCF/BQ/PI19/11690012; the Generalitat Valenciana of Spain under grants PROMETEO/2016/120 and SEJI/2017/011; the Portuguese FCT under project PTDC/FIS-NUC/2525/2014 and under projects UID/FIS/04559/2020 to fund the activities of LIBPhys-UC; the Pazy Foundation (Israel) under grants 877040 and 877041; the US Department of Energy under contracts number DE-AC02-06CH11357 (Argonne National Laboratory, USA), DE-AC02-07CH11359 (Fermi National Accelerator Laboratory), DE-FG02-13ER42020 (Texas A&M). DGD acknowledges support from the Ramón y Cajal program (Spain) under contract number RYC-2015-18820. JM-A acknowledges support from Fundación Bancaria la Caixa (ID 100010434), grant code LCF/BQ/PI19/11690012, and from the Plan GenT program of the Generalitat Valenciana , grant code CIDEGENT/2019/049.Peer reviewe

    Las obsesiones antes de Freud: historia y clínica

    Full text link

    Experimental studies of neutrino nature: from K2K to SuperNEMO

    Get PDF
    297 páginas. Tesis Doctoral del Departamento de Física Atómica,Molecular y Nuclear de la Universidad de Valencia, y el Instituto de Física Corpuscular (IFIC). Fecha de lectura: 06-12-2009El objetivo de este trabajo es estudiar desde un punto de vista experimental dos aspectos fundamentales de la naturaleza de los neutrinos, el fenómeno de las oscilaciones y su masa, centrándose en los experimentos en los que el grupo del IFIC (CSIC-UVEG) liderado por JJ Gómez-Cadenas, ha participado en los últimos 5 años. La física que estudia las propiedades de los neutrinos puede ser dividida en dos campos bien diferenciados: el de los experimentos de oscilación y el de los experimentos que tratan de medir la masa absoluta del neutrino. En cuanto a las oscilaciones de neutrinos, se describe en este documento el experimento K2K, que publicó en 2006 una fuerte evidencia de oscilación de neutrinos muónicos, y la aportación del experimento HARP al análisis de K2K. Por otra parte, en relación con el estudio de la naturaleza de la masa de los neutrinos, el presente documento se centra en el existoso experimento de desintegración doble beta sin emisión de neutrinos (bb0nu) NEMO-3, y en el proyecto llamado SuperNEMO.Peer reviewe

    The Antineutrino Energy Structure in Reactor Experiments

    No full text
    The publication of this article was funded by SCOAP 3 . The recent observation of an energy structure in the reactor antineutrino spectrum is reviewed. The reactor experiments Daya Bay, Double Chooz, and RENO have reported a consistent excess of antineutrinos deviating from the flux predictions, with a local significance of about 4 between 4 and 6 MeV of the positron energy spectrum. The possible causes of the structure are analyzed in this work, along with the different experimental approaches developed to identify its origin. Considering the available data and results from the three experiments, the most likely explanation concerns the reactor flux predictions and the associated uncertainties. Therefore, the different current models are described and compared. The possible sources of incompleteness or inaccuracy of such models are discussed, as well as the experimental data required to improve their precision

    Simultaneous measurement of the muon neutrino charged-current cross section on oxygen and carbon without pions in the final state at T2K

    No full text
    This paper reports the first simultaneous measurement of the double differential muon neutrino charged-current cross section on oxygen and carbon without pions in the final state as a function of the outgoing muon kinematics, made at the ND280 off-axis near detector of the T2K experiment. The ratio of the oxygen and carbon cross sections is also provided to help validate various models' ability to extrapolate between carbon and oxygen nuclear targets, as is required in T2K oscillation analyses. The data are taken using a neutrino beam with an energy spectrum peaked at 0.6 GeV. The extracted measurement is compared with the prediction from different Monte Carlo neutrino-nucleus interaction event generators, showing particular model separation for very forward-going muons. Overall, of the models tested, the result is best described using local Fermi gas descriptions of the nuclear ground state with RPA suppression
    corecore