Papers by Gustavo Valdiviesso
Proceedings of The 22nd International Workshop on Neutrinos from Accelerators — PoS(NuFact2021), Mar 31, 2022
The word arapuca refers to a bird trap built by the indigenous peoples of Brazil. On the other ha... more The word arapuca refers to a bird trap built by the indigenous peoples of Brazil. On the other hand, our ARAPUCA is a photon trap for Noble Gases' scintillation light and it is the sensitive element upon which DUNE's whole photon detection system is based on. Here we present a glimpse of our state-of-the-art simulation of such device, the ArapucaSim, highlighting its philosophy and main components. As an application, we present here one of the studies being carried out, on the effects of light reflections inside the light guide and how affects the overall photon detection efficiency. Based on these results, we are able to not only acquire a better understanding of the device but also impose limits on the quality of the mechanical polishing of such surfaces. The ArapucaSim was developed with two main goals in mind: to assist in R&D by allowing short turnout times between new ideas and experimental tests, and to bridge the gap between highprecision time-consuming hardware simulations and the full-scale models for DUNE's Photon Detection System. This research also led to the development new algorithms for simulating wavelength shifting/scintillation processes and dichroic filters, which will be properly described in future publications.
Proceedings of The 22nd International Workshop on Neutrinos from Accelerators — PoS(NuFact2021), Mar 31, 2022
The word arapuca refers to a bird trap built by the indigenous peoples of Brazil. On the other ha... more The word arapuca refers to a bird trap built by the indigenous peoples of Brazil. On the other hand, our ARAPUCA is a photon trap for Noble Gases' scintillation light and it is the sensitive element upon which DUNE's whole photon detection system is based on. Here we present a glimpse of our state-of-the-art simulation of such device, the ArapucaSim, highlighting its philosophy and main components. As an application, we present here one of the studies being carried out, on the effects of light reflections inside the light guide and how affects the overall photon detection efficiency. Based on these results, we are able to not only acquire a better understanding of the device but also impose limits on the quality of the mechanical polishing of such surfaces. The ArapucaSim was developed with two main goals in mind: to assist in R&D by allowing short turnout times between new ideas and experimental tests, and to bridge the gap between highprecision time-consuming hardware simulations and the full-scale models for DUNE's Photon Detection System. This research also led to the development new algorithms for simulating wavelength shifting/scintillation processes and dichroic filters, which will be properly described in future publications.
× 10 −21 , tan 2 θ = 0, 478 +0,040 −0,038 e ∆m 2 = 7, 73 +0,17 −0,20 × 10 −5 eV 2 (77, 7% C.L.). ... more × 10 −21 , tan 2 θ = 0, 478 +0,040 −0,038 e ∆m 2 = 7, 73 +0,17 −0,20 × 10 −5 eV 2 (77, 7% C.L.). Ambas soluções melhoram o nível de confiança com relaçãoà solução MSW (tan 2 θ = 0, 462 +0,043 −0,036 e ∆m 2 = 7, 75 +0,16 −0,12 × 10 −5 eV 2 , 73, 1% C.L.) Um limite superior para VEP foi obtido como sendo |φ∆γ| ≤ 1, 3 × 10 −20 (3σ) sobre a solução MSW.
How Does the Mass Transfer Restriction Change the Reaction’s Kinetic Order for Acid Mine Drainage Treatment in an Anaerobic Bioreactor?
Lecture Notes in Civil Engineering, 2017
In this work was described the acid mine drainage treatment in an anaerobic bioreactor, where was... more In this work was described the acid mine drainage treatment in an anaerobic bioreactor, where was evaluated the mass transfer resistance’s effects on appearance of the reaction’s kinetic order using a mathematical model, Malthus-Monod-Fick model.
Environmental Technology, 2020
Sulfate and chemical oxygen demand removal by an anaerobic batch reactor treating of acid mine dr... more Sulfate and chemical oxygen demand removal by an anaerobic batch reactor treating of acid mine drainage is modeled. Available models are abundant but excessively complex, with large numbers of free parameters. Here, maximum likelihood and chi-squared hypothesis tests are applied to three simple models, with Malthus-Monod and Fick description, in increasing order of complexity: (i) planktonic single population (of sulfate reducing bacteria); (ii) planktonic double-competing populations (adding fermentative bacteria); (iii) granule bound double-competing populations. The data set consists of 6 timeprofiles, sampled from 120 days of operation after stabilization of the reactor in pH 4. Single population is refuted by all profiles, in which the sulfate reduction is 72% larger than fermentatives. The planktonic double-competing population description is refuted at 119 days, with inner granule diffusion rate as low as 10% of the previous period. The results showed that, after an operation time, the influence of mass transfer became more evident and the incorporation of Fick's law in the model was fundamental to the description of this trend. All tests and inferences are performed at the 90% confidence interval due to large
Compreendendo a oscila��o dos neutrinos
Rev Bras Ensino Fis, 2005
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2016
A compact surface detector designed to identify the inverse beta decay interaction produced by an... more A compact surface detector designed to identify the inverse beta decay interaction produced by antineutrinos coming from near operating nuclear reactors is being developed by the Neutrinos Angra Collaboration. In this document we describe and test the detector and its readout system by means of cosmic rays acquisition. In this measurement campaign, the target detector has been equipped with 16 8-in PMTs and two scintillator paddles have been used to trigger cosmic ray events. The achieved results disclosed the main operational characteristics of the Neutrinos Angra system and have been used to assess the detector and to validate its readout system.
AIP Conference Proceedings, 2015
Mathematical modeling of an horizontal-flow anaerobic immobilized biomass (HAIB) reactor treating acid mine drainage
Horizontal-flow anaerobic immobilized biomass (HAIB) reactor has been successfully use for the tr... more Horizontal-flow anaerobic immobilized biomass (HAIB) reactor has been successfully use for the treatment of acid mine drainage (AMD), however, little attention has been heeded in the understanding of the complex process that takes place in the reactor. In this study a mathematical model of this process was developed, implemented and tested with experimental data. The model is composed by a set of 8 partial differential equations, in which Monod-type function were used for the biomass growth rate. The study includes a model simulation with fixed parameters in MathLab® and a model fitting in C both of them with results from a HAIB reactor treating AMD. The fitting results showed correlation with the proposed model and measured values with better correlation to profile data than operation data. Nomenclature µ mAB maximum specific acidogenic growth rate, d -1 SRB sulfate reducing bacteria µ mSOB maximum specific SOB growth rate, d -1 S Ac acetate concetration, g l -1 µ mSRBc maximum spe...
Stronger Limits for the Violation of Equivalence Principle from Atmospheric Neutrino Data
We re-examine the limits for the Violation of Equivalence Principle (VEP) using updated observati... more We re-examine the limits for the Violation of Equivalence Principle (VEP) using updated observations from solar and reactor neutrino experiments and for the first time including the atmospheric neutrino data. The VEP phenomena can induce muon to electron neutrino oscillations and distort the neutrino zenith distribution. Due to their higher energy, the inclusion of atmospheric neutrinos in the full analysis imposes significantly stronger constraints on the relevant VEP parameters, on all neutrino sectors. ABSTRACT
Model and simulation of the autotrophic denitrification of synthetic wastewater, using elemental sulphur as electron donor, considering a Gompertz model for biomass growth
Neutrinos ANGRA: new simulation results and status of the detector construction
Equivalence principle from the solar and reactor neutrino observations
Nuclear Physics B - Proceedings Supplements, 2012
ABSTRACT A model for the Violation of the Equivalence Principle (VEP) on solar and reactor neutri... more ABSTRACT A model for the Violation of the Equivalence Principle (VEP) on solar and reactor neutrinos is investigated. New limits for the VEP are obtained considering the mass-flavor mixing hypothesis and the VEP model. Our analysis shows two solutions where the VEP effects practically do not change the solar sector. In a first case, the mass scale of the reactor sector remains the same and in a second situation this scale falls slightly, becoming closer to the solar solution without VEP. We improved by two orders of magnitude the upper limits of the relevant VEP parameters.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2014
We describe a muon track reconstruction algorithm for the reactor anti-neutrino experiment Double... more We describe a muon track reconstruction algorithm for the reactor anti-neutrino experiment Double Chooz. The Double Chooz detector consists of two optically isolated volumes of liquid scintillator viewed by PMTs, and an Outer Veto above these made of crossed scintillator strips. Muons are reconstructed by their Outer Veto hit positions along with timing information from the other two detector volumes. All muons are fit under the hypothesis that they are through-going and ultrarelativistic. If the energy depositions suggest that the muon may have stopped, the reconstruction fits also for this hypothesis and chooses between the two via the relative goodness-of-fit. In the ideal case of a through-going muon intersecting the center of the detector, the resolution is ∼40 mm in each transverse dimension. High quality muon reconstruction is an important tool for reducing the impact of the cosmogenic isotope background in Double Chooz.
The Double Chooz experiment presents an indication of reactor electron antineutrino disappearance... more The Double Chooz experiment presents an indication of reactor electron antineutrino disappearance consistent with neutrino oscillations. An observed-to-predicted ratio of events of 0:944 AE 0:016ðstatÞ AE 0:040ðsystÞ was obtained in 101 days of running at the Chooz nuclear power plant in France, with two 4:25 GW th reactors. The results were obtained from a single 10 m 3 fiducial volume detector located 1050 m from the two reactor cores. The reactor antineutrino flux prediction used the Bugey4 flux measurement after correction for differences in core composition. The deficit can be interpreted as an indication of a nonzero value of the still unmeasured neutrino mixing parameter sin 2 2 13. Analyzing both the rate of the prompt positrons and their energy spectrum, we find sin 2 2 13 ¼ 0:086 AE 0:041ðstatÞ AE 0:030ðsystÞ, or, at 90% C.L., 0:017 < sin 2 2 13 < 0:16.
Brazilian Community Report on Dark Matter This white paper summarizes the activities of the Brazi... more Brazilian Community Report on Dark Matter This white paper summarizes the activities of the Brazilian community concerning dark matter physics and highlights the importance of financial support to Brazilian groups that are deeply involved in experimental endeavours. The flagships of the Brazilian dark matter program are the Cherenkov Telescope Array, DARKSIDE, SBN and LHC experiments, but we emphasize that smaller experiments such as DAMIC and CONNIE constitute important probes to dark sectors as well and should receive special attention. Small experimental projects showing the potential to probe new regions of parameter space of dark matter models are encouraged. On the theoretical and phenomenological side, some groups are devoted to astrophysical aspects such as the dark matter density profile while others explore the signature of dark matter models at colliders, direct and indirect detection experiments. In summary, the Brazilian dark matter community that was born not long ago ...
Frontiers in Artificial Intelligence
In liquid argon time projection chambers exposed to neutrino beams and running on or near surface... more In liquid argon time projection chambers exposed to neutrino beams and running on or near surface levels, cosmic muons, and other cosmic particles are incident on the detectors while a single neutrino-induced event is being recorded. In practice, this means that data from surface liquid argon time projection chambers will be dominated by cosmic particles, both as a source of event triggers and as the majority of the particle count in true neutrino-triggered events. In this work, we demonstrate a novel application of deep learning techniques to remove these background particles by applying deep learning on full detector images from the SBND detector, the near detector in the Fermilab Short-Baseline Neutrino Program. We use this technique to identify, on a pixel-by-pixel level, whether recorded activity originated from cosmic particles or neutrino interactions.
European Physical Journal C, Mar 31, 2022
Liquid argon time projection chamber detector technology provides high spatial and calorimetric r... more Liquid argon time projection chamber detector technology provides high spatial and calorimetric resolutions on the charged particles traversing liquid argon. As a result, the technology has been used in a number of recent neutrino experiments, and is the technology of choice for the Deep Underground Neutrino Experiment (DUNE). In order to perform high precision measurements of neutrinos in the detector, final state particles need to be effectively identified, and their energy accurately reconstructed. This article proposes an algorithm based on a convolutional neural network to perform the classification of energy deposits and reconstructed particles as track-like
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Papers by Gustavo Valdiviesso