Absorption Cross Section and Photoluminescence Lifetime of Silicon-Based Light-Emitting nc-Si-SiOx Structures

The spectral dependence of the photoluminescence (PL) decay kinetics at room temperature have been studied in porous nc-Si-SiOx nanostructures. Investigated samples were obtained by oblique evaporation of SiO with following annealing at 975 C in vacuum and treating in the HF vapor at 50 C. PL decay in these structures described by a stretched exponential and the average lifetime of the PL decrease exponentially with increasing energy of photons. PL lifetime values is in microsecond range that point out on phonon participation in radiative recombination. Dispersion parameter do not depend on emission energy and tends to 1 with increasing porosity, which is consistent with the model of noninteracting nc-Si. It was established, that the absorption cross section σ of the nc-Si particles increase with decreasing of nc-Si dimensions and increasing of emission energy. This result is consistent with the quantum confinement effects, where the smaller nc-Si with larger energy gaps are characterized by a short radiative lifetime and the corresponding radiative recombination process take place within the individual nc-Si. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3501

Immersion Lithography with Using of Photostimulated Etching of Germanium Chalcogenide Films

The new effect of photo-stimulated dissolution of as-evaporated and annealed Ge-based chalcogenide glass (ChG) films was investigated. The etching rate increases with the illumination intensity, and its spectral dependence is correlated with absorption in the film at the absorption edge. The high-frequency diffraction gratings on germanium ChG - more environmentally acceptable compounds than traditionally used arsenic chalcogenides, were recorded by method of interference immersion photolithography with photoinduced etching. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3563

Measurements of atmospheric neutrinos and antineutrinos in the MINOS far detector

This paper reports measurements of atmospheric neutrino and antineutrino interactions in the MINOS Far Detector, based on 2553 live-days (37.9kton-years) of data. A total of 2072 candidate events are observed. These are separated into 905 contained-vertex muons and 466 neutrino-induced rock-muons, both produced by charged-current ν μ and ν ̄μ interactions, and 701 contained-vertex showers, composed mainly of charged-current ν e and ν ̄e interactions and neutral-current interactions. The curvature of muon tracks in the magnetic field of the MINOS Far Detector is used to select separate samples of ν μ and ν ̄μ events. The observed ratio of ν ̄μ to ν μ events is compared with the MonteCarlo (MC) simulation, giving a double ratio of Rν̄/νdata/ Rν̄/νMC=1.03±0.08(stat)±0.08(syst). The ν μ and ν ̄μ data are separated into bins of L/E resolution, based on the reconstructed energy and direction of each event, and a maximum likelihood fit to the observed L/E distributions is used to determine the atmospheric neutrino oscillation parameters. This fit returns 90% confidence limits of |Δm2|=(1.9±0.4)×10 -3eV2 and sin22θ>0.86. The fit is extended to incorporate separate ν μ and ν ̄μ oscillation parameters, returning 90% confidence limits of |Δm2|-|Δm ̄2|=0.6- 0.8+2.4×10 -3eV2 on the difference between the squared-mass splittings for neutrinos and antineutrinos. © 2012 American Physical Society

Improved search for muon-neutrino to electron-neutrino oscillations in MINOS

We report the results of a search for νe appearance in a νμ beam in the MINOS long-baseline neutrino experiment. With an improved analysis and an increased exposure of 8.2×1020 protons on the NuMI target at Fermilab, we find that 2sin2(θ23) sin2(2θ13)<0.12(0.20) at 90% confidence level for δ=0 and the normal (inverted) neutrino mass hierarchy, with a best-fit of 2sin2(θ23)sin2(2θ13)=0. 041-0.031+0.047(0.079-0.053+0.071). The θ13=0 hypothesis is disfavored by the MINOS data at the 89% confidence level. © 2011 American Physical Society

Observation in the MINOS far detector of the shadowing of cosmic rays by the sun and moon

The shadowing of cosmic ray primaries by the moon and sun was observed by the MINOS far detector at a depth of 2070 mwe using 83.54 million cosmic ray muons accumulated over 1857.91 live-days. The shadow of the moon was detected at the 5.6 σ level and the shadow of the sun at the 3.8 σ level using a log-likelihood search in celestial coordinates. The moon shadow was used to quantify the absolute astrophysical pointing of the detector to be 0.17 ± 0.12°. Hints of interplanetary magnetic field effects were observed in both the sun and moon shadow. © 2010 Elsevier B.V. All rights reserved

Search for lorentz invariance and CPT violation with the MINOS Far detector

We searched for a sidereal modulation in the MINOS far detector neutrino rate. Such a signal would be a consequence of Lorentz and CPT violation as described by the standard-model extension framework. It also would be the first detection of a perturbative effect to conventional neutrino mass oscillations. We found no evidence for this sidereal signature, and the upper limits placed on the magnitudes of the Lorentz and CPT violating coefficients describing the theory are an improvement by factors of 20-510 over the current best limits found by using the MINOS near detector. © 2010 The American Physical Society

Observation in the MINOS far detector of the shadowing of cosmic rays by the sun and moon

The shadowing of cosmic ray primaries by the moon and sun was observed by the MINOS far detector at a depth of 2070 mwe using 83.54 million cosmic ray muons accumulated over 1857.91 live-days. The shadow of the moon was detected at the 5.6 σ level and the shadow of the sun at the 3.8 σ level using a log-likelihood search in celestial coordinates. The moon shadow was used to quantify the absolute astrophysical pointing of the detector to be 0.17 ± 0.12°. Hints of interplanetary magnetic field effects were observed in both the sun and moon shadow

Observation in the MINOS far detector of the shadowing of cosmic rays by the sun and moon

The shadowing of cosmic ray primaries by the moon and sun was observed by the MINOS far detector at a depth of 2070 mwe using 83.54 million cosmic ray muons accumulated over 1857.91 live-days. The shadow of the moon was detected at the 5.6 sigma level and the shadow of the sun at the 3.8 sigma level using a log-likelihood search in celestial coordinates. The moon shadow was used to quantify the absolute astrophysical pointing of the detector to be 0.17 +/- 0.12 degrees. Hints of interplanetary magnetic field effects were observed in both the sun and moon shadow. Published by Elsevier B.V

Search for muon-Neutrino to electron-Neutrino transitions in MINOS

This Letter reports on a search for νμ→νe transitions by the MINOS experiment based on a 3.14×1020 protons-on-target exposure in the Fermilab NuMI beam. We observe 35 events in the Far Detector with a background of 27±5(stat)±2(syst) events predicted by the measurements in the Near Detector. If interpreted in terms of νμ→νe oscillations, this 1.5σ excess of events is consistent with sin 2(2θ13) comparable to the CHOOZ limit when |Δm2|=2.43×10-3eV2 and sin 2(2θ23)=1.0 are assumed. © 2009 The American Physical Society