Antineutrino flux from the Laguna Verde Nuclear Power Plant

We present a calculation of the antineutrino flux produced by the reactors at the Laguna Verde Nuclear Power Plant in M\'exico, based on the antineutrino spectra produced in the decay chains of the fission fragments of the main isotopes in the reactor core, and their fission rates, that have been calculated using the DRAGON simulation code. We also present an estimate of the number of expected events in a detector made of plastic scintillator with a mass of 1 ton, at 100 m from the reactor cores.Comment: 15 pages, 8 figures, 4 table

Magnus Expansion and Three-Neutrino Oscillations in Matter

We present a semi-analytical derivation of the survival probability of solar neutrinos in the three generation scheme, based on the Magnus approximation of the evolution operator of a three level system, and assuming a mass hierarchy among neutrino mass eigenstates. We have used an exponential profile for the solar electron density in our approximation. The different interesting density regions that appear throughout the propagation are analyzed. Finally, some comments on the allowed regions in the solar neutrino parameter space are addressed.Comment: RevTex4 style, 5 pages including 5 figures. Presented at Mexican School of Astrophysics 2002, Guanajuato, Mexico, 31 Jul - 7 Aug 2002. Final version to appear in the Proceedings of IX Mexican Workshop on Particles and Fields Physics Beyond the Standard Model, Colima Col. Mexico, November 17-22, 200

Active neutrino Oscillations and the SNO neutral Current measurement

We discuss the relation between the observed CC, ES, and NC fluxes with the flavor fractional content of the solar neutrino flux seen by SNO. By using existing estimates of the cross sections for the charged and neutral current reactions which take into account the detector resolution, we show how the forthcoming SNO rates unconstrained by the standard $^8$B shape could test the oscillations into active states. We perform a model independent analysis for the Super-K and SNO data, assuming a non distorted spectrum.Comment: 6pages, 4 figure

A search for muon neutrino and antineutrino disappearance in MiniBooNE

The MiniBooNE Collaboration reports a search for {nu}{sub {mu}} and {bar {nu}}{sub {mu}} disappearance in the {Delta}m{sup 2} region of a few eV{sup 2}. These measurements are important for constraining models with extra types of neutrinos, extra dimensions and CPT violation. Fits to the shape of the {nu}{sub {mu}} and {bar {nu}}{sub {mu}} energy spectra reveal no evidence for disappearance at 90% confidence level (CL) in either mode. This is the first test of {bar {nu}}{sub {mu}} disappearance between {Delta}m{sup 2} = 0.1-10 eV{sup 2}

Search for coherent elastic neutrino-nucleus scattering at a nuclear reactor with CONNIE 2019 data

The Coherent Neutrino-Nucleus Interaction Experiment (CONNIE) is taking data at the Angra 2 nuclear reactor with the aim of detecting the coherent elastic scattering of reactor antineutrinos with silicon nuclei using charge-coupled devices (CCDs). In 2019 the experiment operated with a hardware binning applied to the readout stage, leading to lower levels of readout noise and improving the detection threshold down to 50 eV. The results of the analysis of 2019 data are reported here, corresponding to the detector array of 8 CCDs with a fiducial mass of 36.2 g and a total exposure of 2.2 kg-days. The difference between the reactor-on and reactor-off spectra shows no excess at low energies and yields upper limits at 95% confidence level for the neutrino interaction rates. In the lowest-energy range, 50-180 eV, the expected limit stands at 34 (39) times the standard model prediction, while the observed limit is 66 (75) times the standard model prediction with Sarkis (Chavarria) quenching factors.Comment: 23 pages, 14 figure

Dosimetry and calorimetry performance of a scientific CMOS camera for environmental monitoring

This paper explores the prospect of CMOS devices to assay lead in drinking water, using calorimetry. Lead occurs together with traces of radioisotopes, e.g.,210 Pb, producing γ-emissions with energies ranging from 10 keV to several 100 keV when they decay; this range is detectable in silicon sensors. In this paper we test a CMOS camera (OXFORD INSTRUMENTS Neo 5.5) for its general performance as a detector of X-rays and low energy γ-rays and assess its sensitivity relative to the World Health Organization upper limit on lead in drinking water. Energies from 6 keV to 60 keV are examined. The CMOS camera has a linear energy response over this range and its energy resolution is for the most part slightly better than 2%. The Neo sCMOS is not sensitive to X-rays with energies below ∼ 10 keV. The smallest detectable rate is 40 ± 3 mHz, corresponding to an incident activity on the chip of 7 ± 4 Bq. The estimation of the incident activity sensitivity from the detected activity relies on geometric acceptance and the measured efficiency vs. energy. We report the efficiency measurement, which is 0.08(2)% (0.0011(2)%) at 26.3 keV (59.5 keV). Taking calorimetric information into account we measure a minimal detectable rate of 4 ± 1 mHz (1.5 ± 0.1 mHz) for 26.3 keV (59.5 keV) γ-rays, which corresponds to an incident activity of 1.0 ± 0.6 Bq (57 ± 33 Bq). Toy Monte Carlo and Geant4 simulations agree with these results. These results show this CMOS sensor is well-suited as a γ-and X-ray detector with sensitivity at the few to 100 ppb level for210 Pb in a sample

Skipper-CCD Sensors for the Oscura Experiment: Requirements and Preliminary Tests

Oscura is a proposed multi-kg skipper-CCD experiment designed for a dark matter (DM) direct detection search that will reach unprecedented sensitivity to sub-GeV DM-electron interactions with its 10 kg detector array. Oscura is planning to operate at SNOLAB with 2070 m overburden, and aims to reach a background goal of less than one event in each electron bin in the 2-10 electron ionization-signal region for the full 30 kg-year exposure, with a radiation background rate of 0.01 dru. In order to achieve this goal, Oscura must address each potential source of background events, including instrumental backgrounds. In this work, we discuss the main instrumental background sources and the strategy to control them, establishing a set of constraints on the sensors' performance parameters. We present results from the tests of the first fabricated Oscura prototype sensors, evaluate their performance in the context of the established constraints and estimate the Oscura instrumental background based on these results