443 research outputs found
Behaviour in Magnetic Fields of Fast Conventional and Fine-Mesh Photomultipliers
The performance of both conventional and fine-mesh Hamamatsu photomultipliers
has been measured inside moderate magnetic fields. This has allowed the test of
effective shielding solutions for photomultipliers, to be used in
time-of-flight detectors based on scintillation counters. Both signal amplitude
reduction or deterioration of the timing properties inside magnetic fields have
been investigated
Atributos anatômicos de lâminas foliares de Paspalum spp.
Gramíneas do gênero Paspalum spp. apresentam alto potencial para o melhoramento genético, devido à sua grande variabilidade genética. Este estudo, conduzido na Universidade Federal da Grande Dourados, teve como objetivo avaliar atributos anatômicos de lâminas foliares de Paspalum spp. (P. malacophyllum - P30, P. guenoarum - P65, P. glaucescens - P114, P. spp.- Pl16, P. spp. - P127, P. guenoarum - P148, P. regnellii - P191 e uma cultivar comercial- P. alralum cv. Pojuca). Utilizou-se o delineamento de blocos ao acaso, oito genótipos e quatro repetições. Os fragmentos das lâminas foram fixados em F AA e após efetuou-se o preparo histológico. Alta variabilidade entre os genótipos foi observada quanto à proporção e arranjo de tecidos, e presença de tanino condensado na epiderme. Dos caracteres avaliados a presença de estrutura girder, foi a que mais discriminou os genótipos quanto ao potencial qualitativo das lâminas. Estudos devem ser conduzidos para verificar o efeito do tanino condensado, presente na epiderme, no potencial qualitativo dos genótipos
The design and commissioning of the MICE upstream time-of-flight system
In the MICE experiment at RAL the upstream time-of-flight detectors are used
for particle identification in the incoming muon beam, for the experiment
trigger and for a precise timing (sigma_t ~ 50 ps) with respect to the
accelerating RF cavities working at 201 MHz. The construction of the upstream
section of the MICE time-of-flight system and the tests done to characterize
its individual components are shown. Detector timing resolutions ~50-60 ps were
achieved. Test beam performance and preliminary results obtained with beam at
RAL are reported.Comment: accepted on Nuclear Instruments and Methods
Simulation of Auger decay dynamics in the hard X-ray regime: HCl as a showcase
Auger decay after photoexcitation or photoemission of an electron from a deep inner shell in the hard X-ray regime can be rather complex, implying a multitude of phenomena such as multiple-step cascades, post-collision interaction (PCI), and electronic state-lifetime interference. Furthermore, in a molecule nuclear motion can also be triggered. Here we discuss a comprehensive theoretical method which allows us to analyze in great detail Auger spectra measured around an inner-shell ionization threshold. HCl photoexcited or photoionized around the deep Cl 1s threshold is chosen as a showcase. Our method allows calculating Auger cross sections considering the nature of the ground, intermediate and final states (bound or dissociative), and the evolution of the relaxation process, including both electron and nuclear dynamics. In particular, we show that we can understand and reproduce a so-called experimental 2D-map, consisting of a series of resonant Auger spectra measured at different photon energies, therefore obtaining a detailed picture of all above-mentioned dynamical phenomena at once
Four Zero Texture Fermion Mass Matrices in SO(10) GUT
We attempt the integration of the phenomenologically successful four zero
texture of fermion mass matrices with the renormalizable SO(10) GUT. The
resulting scenario is found to be highly predictive. Firstly, we examine the
phenomenological implications of a class of the lepton mass matrices with
parallel texture structures and obtain interesting constraints on the
parameters of the charged lepton and the neutrino mass matrices. We combine
these phenomenological constraints with the constraints obtained from SO(10)
GUT to reduce the number of the free parameters and to further constrain the
allowed ranges of the free parameters. The solar/atmospheric mixing angles
obtained in this analysis are in fairly good agreement with the data.Comment: 14 pages, 3 figures, 1 tabl
Variability of Nitrous Oxide and Methane emissions from soils under Eucalyptus forests in the Cerrado (Brazilian savanna).
Plantas medicinais utilizadas pelos agricultores ecológicos na região sul do Rio Grande do Sul.
bitstream/item/52349/1/Documento-332-1.pd
Measurements of KL Branching Fractions and the CP Violation Parameter |eta+-|
We present new measurements of the six largest branching fractions of the KL
using data collected in 1997 by the KTeV experiment (E832) at Fermilab. The
results are B(KL -> pi e nu) = 0.4067 +- 0.0011 B(KL -> pi mu nu) = 0.2701 +-
0.0009 B(KL -> pi+ pi- pi0) = 0.1252 +- 0.0007 B(KL -> pi0 pi0 pi0) = 0.1945 +-
0.0018 B(KL -> pi+ pi-) = (1.975 +- 0.012)E-3, and B(KL -> pi0 pi0) = (0.865 +-
0.010)E-3, where statistical and systematic errors have been summed in
quadrature. We also determine the CP violation parameter |eta+-| to be (2.228
+- 0.010)E-3. Several of these results are not in good agreement with averages
of previous measurements.Comment: Submitted to Phys. Rev. D; 20 pages, 22 figure
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