Sulfate and chemical oxygen demand removal by an anaerobic batch reactor treating of acid mine drainage is modelled. 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 time profiles, 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
larger than fermentatives. The planktonic double-competing population description is refuted at 119 days, with inner granule diffusion rate as low as
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
confidence interval due to large systematic uncertainties in the data.
New limits for the Violation of the Equivalence Principle (VEP) are obtained considering the mass-flavor mixing hypothesis. This analysis includes observations of solar and reactor neutrinos and has ...obtained a limit for the VEP parameter |Δγ| contributing to the νe and ν¯e disappearance channels of the order |Δγ|<10−14, when it is assumed that neutrinos are mainly affected by the gravitational potential ϕ≈10−5 due to the Great Attractor.
A compact surface detector designed to identify the inverse beta decay interaction produced by anti-neutrinos 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.
We present the status of the Angra Neutrino Experiment, aimed at developing an antineutrino detector for monitoring nuclear reactor activity. The detector comprises a 1.42 m3 Gadolinium-Water ...Cerenkov target, surrounded by 50 cm of water shielding, placed inside a commercial container about 30 m from the reactor core, at the Angra II nuclear power plant, Brazil. The 4 GW thermal power of the Angra II reactor will provide a few thousand antineutrino interactions per day. The main challenge of the experiment is to overcome the very high cosmic ray induced background at sea level. The present text describes the construction status and simulations results.
A
bstract
The Double Chooz experiment measures the neutrino mixing angle
θ
13
by detecting reactor
ν
¯
e
via inverse beta decay. The positron-neutron space and time coincidence allows for a sizable ...background rejection, nonetheless liquid scintillator detectors would profit from a positron/electron discrimination, if feasible in large detector, to suppress the remaining background. Standard particle identification, based on particle dependent time profile of photon emission in liquid scintillator, can not be used given the identical mass of the two particles. However, the positron annihilation is sometimes delayed by the ortho-positronium (o-Ps) metastable state formation, which induces a pulse shape distortion that could be used for positron identification. In this paper we report on the first observation of positronium formation in a large liquid scintillator detector based on pulse shape analysis of single events. The o-Ps formation fraction and its lifetime were measured, finding the values of 44 % ±12 % (sys.) ±5 % (stat.) and 3.68 ns ±0.17 ns (sys.) ±0.15 ns (stat.) respectively, in agreement with the results obtained with a dedicated positron annihilation lifetime spectroscopy setup.
The recent high-statistics high-energy atmospheric neutrino data collected by IceCube open a new window to probe new physics scenarios that are suppressed in lower-energy neutrino experiments. In ...this paper we analyze the IceCube atmospheric neutrino data to constrain the violation of equivalence principle (VEP) in the framework of three neutrinos with nonuniversal gravitational couplings. In this scenario the effect of the VEP on neutrino oscillation probabilities can be parametrized by two parameters, Delta gamma sub(21) = gamma sub(2) - gamma sub(1) and Delta gamma sub(31) = gamma sub(3) - gamma sub(1), where gamma sub()i's denote the coupling of neutrino mass eigenstates to the gravitational field. By analyzing the latest muon-tracks data sets of IceCube-40 and IceCube-79, besides providing the two-dimensional allowed regions in the (varphi Delta gamma sub(21), varphi Delta gamma sub(31)) plane, we obtain the upper limits varphi Delta gamma sub(21) < 9.1 x 10 super(-27) (at 90% C.L.), which improves the previous limit by ~ 4 orders of magnitude, and varphi Delta gamma sub(31) <, ~ 6 x 10 super(-27) (at 90% C.L.), which improves the current limit by ~ 1 order of magnitude. Also we discuss in detail and analytically the effect of the VEP on neutrino oscillation probabilities.
SBND is the near detector of the Short-Baseline Neutrino program at Fermilab. Its location near to the Booster Neutrino Beam source and relatively large mass will allow the study of neutrino ...interactions on argon with unprecedented statistics. This paper describes the expected performance of the SBND photon detection system, using a simulated sample of beam neutrinos and cosmogenic particles. Its design is a dual readout concept combining a system of 120 photomultiplier tubes, used for triggering, with a system of 192 X-ARAPUCA devices, located behind the anode wire planes. Furthermore, covering the cathode plane with highly-reflective panels coated with a wavelength-shifting compound recovers part of the light emitted towards the cathode, where no optical detectors exist. We show how this new design provides a high light yield and a more uniform detection efficiency, an excellent timing resolution and an independent 3D-position reconstruction using only the scintillation light. Finally, the whole reconstruction chain is applied to recover the temporal structure of the beam spill, which is resolved with a resolution on the order of nanoseconds.
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 semantic segmentation on full detector images from the SBND detector, the near detector in the Fermilab Short-Baseline Neutrino Program. We use this technique to identify, at single image-pixel level, whether recorded activity originated from cosmic particles or neutrino interactions.
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