117 research outputs found
Reactor Neutrino Flux Uncertainty Suppression on Multiple Detector Experiments
This publication provides a coherent treatment for the reactor neutrino flux
uncertainties suppression, specially focussed on the latest
measurement. The treatment starts with single detector in single reactor site,
most relevant for all reactor experiments beyond . 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 . 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 knowledge
today. First, Double Chooz, in its final configuration, is the only experiment
benefiting from a negligible reactor flux error due to a 90\% geometrical
suppression. Second, Daya Bay and RENO could benefit from their partial
geometrical cancellation, yielding a potential 50\% error suppression,
thus significantly improving the global 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
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
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
Identification and reconstruction of low-energy electrons in the ProtoDUNE-SP detector
Measurements of electrons from νe interactions are crucial for the Deep Underground Neutrino Experiment (DUNE) neutrino oscillation program, as well as searches for physics beyond the standard model, supernova neutrino detection, and solar neutrino measurements. This article describes the selection and reconstruction of low-energy (Michel) electrons in the ProtoDUNE-SP detector. ProtoDUNE-SP is one of the prototypes for the DUNE far detector, built and operated at CERN as a charged particle test beam experiment. A sample of low-energy electrons produced by the decay of cosmic muons is selected with a purity of 95%. This sample is used to calibrate the low-energy electron energy scale with two techniques. An electron energy calibration based on a cosmic ray muon sample uses calibration constants derived from measured and simulated cosmic ray muon events. Another calibration technique makes use of the theoretically well-understood Michel electron energy spectrum to convert reconstructed charge to electron energy. In addition, the effects of detector response to low-energy electron energy scale and its resolution including readout electronics threshold effects are quantified. Finally, the relation between the theoretical and reconstructed low-energy electron energy spectra is derived, and the energy resolution is characterized. The low-energy electron selection presented here accounts for about 75% of the total electron deposited energy. After the addition of lost energy using a Monte Carlo simulation, the energy resolution improves from about 40% to 25% at 50 MeV. These results are used to validate the expected capabilities of the DUNE far detector to reconstruct low-energy electrons
Hint for a TeV neutrino emission from the Galactic Ridge with ANTARES
Interactions of cosmic ray protons, atomic nuclei, and electrons in the interstellar medium in the inner part of the Milky Way produce a γ-ray flux from the Galactic Ridge. If the γ-ray emission is dominated by proton and nuclei interactions, a neutrino flux comparable to the γ-ray flux is expected from the same sky region. Data collected by the ANTARES neutrino telescope are used to constrain the neutrino flux from the Galactic Ridge in the 1-100 TeV energy range. Neutrino events reconstructed both as tracks and showers are considered in the analysis and the selection is optimized for the search of an excess in the region |l|<30°, |b|<2°. The expected background in the search region is estimated using an off-zone region with similar sky coverage. Neutrino signal originating from a power-law spectrum with spectral index ranging from Γ=1 to 4 is simulated in both channels. The observed energy distributions are fitted to constrain the neutrino emission from the Ridge. The energy distributions in the signal region are inconsistent with the background expectation at ∼96% confidence level. The mild excess over the background is consistent with a neutrino flux with a power law with a spectral index 2.45 and a flux normalization [Formula presented] GeV cm s sr at 40 TeV reference energy. Such flux is consistent with the expected neutrino signal if the bulk of the observed γ-ray flux from the Galactic Ridge originates from interactions of cosmic ray protons and nuclei with a power-law spectrum extending well into the PeV energy range
Reconstruction of interactions in the ProtoDUNE-SP detector with Pandora
The Pandora Software Development Kit and algorithm libraries provide pattern-recognition logic essential to the reconstruction of particle interactions in liquid argon time projection chamber detectors. Pandora is the primary event reconstruction software used at ProtoDUNE-SP, a prototype for the Deep Underground Neutrino Experiment far detector. ProtoDUNE-SP, located at CERN, is exposed to a charged-particle test beam. This paper gives an overview of the Pandora reconstruction algorithms and how they have been tailored for use at ProtoDUNE-SP. In complex events with numerous cosmic-ray and beam background particles, the simulated reconstruction and identification efficiency for triggered test-beam particles is above 80% for the majority of particle type and beam momentum combinations. Specifically, simulated 1 GeV/c charged pions and protons are correctly reconstructed and identified with efficiencies of 86.1 ± 0.6 % and 84.1 ± 0.6 %, respectively. The efficiencies measured for test-beam data are shown to be within 5% of those predicted by the simulation
Radon Mitigation Applications at the Laboratorio Subterraneo de Canfranc (LSC)
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
Impact of cross-section uncertainties on supernova neutrino spectral parameter fitting in the Deep Underground Neutrino Experiment
A primary goal of the upcoming Deep Underground Neutrino Experiment (DUNE) is to measure the O(10) MeV neutrinos produced by a Galactic core-collapse supernova if one should occur during the lifetime of the experiment. The liquid-argon-based detectors planned for DUNE are expected to be uniquely sensitive to the νe component of the supernova flux, enabling a wide variety of physics and astrophysics measurements. A key requirement for a correct interpretation of these measurements is a good understanding of the energy-dependent total cross section σ(Eν) for charged-current νe absorption on argon. In the context of a simulated extraction of supernova νe spectral parameters from a toy analysis, we investigate the impact of σ(Eν) modeling uncertainties on DUNE's supernova neutrino physics sensitivity for the first time. We find that the currently large theoretical uncertainties on σ(Eν) must be substantially reduced before the νe flux parameters can be extracted reliably; in the absence of external constraints, a measurement of the integrated neutrino luminosity with less than 10% bias with DUNE requires σ(Eν) to be known to about 5%. The neutrino spectral shape parameters can be known to better than 10% for a 20% uncertainty on the cross-section scale, although they will be sensitive to uncertainties on the shape of σ(Eν). A direct measurement of low-energy νe-argon scattering would be invaluable for improving the theoretical precision to the needed level
Excerpta Botanica Pharmaceutica
Facultat de Farmàcia, Universitat de Barcelona. Ensenyament: Grau de Farmàcia, Assignatura: Botànica Farmacèutica, Curs: 2013-2014, Coordinadors: Carles Benedí i Joan SimonEl disseny de l’activitat ha estat a càrrec del Grup d’Innovació Docent de Botànica Aplicada a
les Ciències Farmacèutiques (GIBAF), i s’emmarca en el Projecte d’Innovació Docent «Excerpta
Botanica Pharmaceutica: creació de recursos docents en obert pels propis estudiants com a
nova estratègia d’innovació docent» (codi 2014PID-UB/010) del Programa de Millora i
Innovació Docent (PMID) de la Universitat de Barcelona.Amb el nom genèric d’Excerpta Botanica Pharmaceutica (extracte de Botànica Farmacèutica), agrupem els treballs (guies d’estudi) que han redactat de forma tutorizada els estudiants del grup T3 de l’assignatura Botànica Farmacèutica (curs 2013-14). Els objectius específics han estat: aprendre a utilitzar correctament la nomenclatura botànica en la denominació de les espècies, saber redactar ordenadament la descripció d’una espècie amb la terminologia botànica adequada, cercar utilitzar i integrar la informació botànica de referència i proposar-ne d’addicional comentades i fomentar l’aprenentatge autònom i col·laboratiu en Botànica farmacèutica. Els objectius transversals han estat: estimular el compromís ètic (imatges incloses de llicència lliure), desenvolupar una capacitat de síntesi escrita i de tenir visions globals integradores (la monografia aportada), mantenir una pulcritud en el treball i compromís per la feina ben feta (responsabilitat en el futur material d'ús docent per als seus companys, dipòsit digital UB) i fomentar la apacitat autocrítica (la seva autoavaluació)
Design, characterization and installation of the NEXT-100 cathode and electroluminescence regions
The NEXT Collaboration: K. Mistry et al.NEXT-100 is currently being constructed at the Laboratorio Subterráneo de Canfranc in the Spanish Pyrenees and will search for neutrinoless double beta decay using a high-pressure gaseous time projection chamber (TPC) with 100 kg of xenon. Charge amplification is carried out via electroluminescence (EL) which is the process of accelerating electrons in a high electric field region causing secondary scintillation of the medium proportional to the initial charge. The NEXT-100 EL and cathode regions are made from tensioned hexagonal meshes of 1 m diameter. This paper describes the design, characterization, and installation of these parts for NEXT-100. Simulations of the electric field are performed to model the drift and amplification of ionization electrons produced in the detector under various EL region alignments and rotations. Measurements of the electrostatic breakdown voltage in air characterize performance under high voltage conditions and identify breakdown points. The electrostatic deflection of the mesh is quantified and fit to a first-principles mechanical model. Measurements were performed with both a standalone test EL region and with the NEXT-100 EL region before its installation in the detector. Finally, we describe the parts as installed in NEXT-100, following their deployment in Summer 2023.The NEXT Collaboration acknowledges support from the following agencies and institutions: the European Research Council (ERC) under Grant Agreement No. 951281-BOLD; the European Union’s Framework Programme for Research and Innovation Horizon 2020 (2014–2020) under Grant Agreement No. 957202-HIDDEN; the MCIN/AEI of Spain and ERDF A way of making Europe under grants PID2021-125475NB and the Severo Ochoa Program grant CEX2018-000867-S; the Generalitat Valenciana of Spain under grants PROMETEO/2021/087 and CIDEGENT/2019/049; the Department of Education of the Basque Government of Spain under the predoctoral training program non-doctoral research personnel; the Spanish la Caixa Foundation (ID 100010434) under fellowship code LCF/BQ/PI22/11910019; the Portuguese FCT under project UID/FIS/04559/2020 to fund the activities of LIBP ys-UC; the Israel Science Foundation (ISF) under grant 1223/21; the Pazy Foundation (Israel) under grants 310/22, 315/19 and 465; the US Department of Energy under contracts number DE-AC02-06CH11357 (Argonne National Laboratory), DE-AC02-07CH11359 (Fermi National Accelerator Laboratory), DE-FG02-13ER42020 (Texas A&M), DE-SC0019054 (Texas Arlington) and DE-SC0019223 (Texas Arlington); the US National Science Foundation under award number NSF CHE 2004111; the Robert A Welch Foundation under award number
Y-2031-20200401.With funding from the Spanish government through the "Severo Ochoa Centre of Excellence" accreditation (CEX2018-000867-S).Peer reviewe
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