FRANCISCO DE ASSIS SOUZA

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  • Artigo IPEN-doc 29060
    Double-GEM based thermal neutron detector prototype
    2022 - SERRA FILHO, L.A.; FELIX DOS SANTOS, R.; SOUZA, G.G.A. de; PAULINO, M.M.M.; SOUZA, F.A.; MORALLES, M.; LUZ, H.N. da; BREGANT, M.; MUNHOZ, M.G.; LAI, C.-C.; HOGLUND, C.; SVENSSON, P.-O.; ROBINSON, L.; HALL-WILTON, R.
    The Helium-3 shortage and the growing interest in neutron science constitute a driving factor in developing new neutron detection technologies. In this work, we report the development of a double-GEM detector prototype that uses a 10B4C layer as a neutron converter material. GEANT4 simulations were performed predicting an efficiency of (3.14 ± 0.10)%, agreeing within 2.7σ with the experimental and analytic detection efficiencies obtained by the detector when tested in a 41.8 meV thermal neutron beam. The detector is position sensitive, equipped with a 256+256 strip readout connected to resistive chains, and achieves a spatial resolution better than 3 mm. The gain stability over time was also measured with a fluctuation of about 0.2% h-1 of the signal amplitude. A simple data acquisition with only 5 electronic channels is sufficient to operate this detector.
  • Artigo IPEN-doc 28300
    Performance and optimization of a GEM-based neutron detector using a parameterized fast simulator
    2021 - SANTOS, R.F. dos; SERRA FILHO, L.A.; MUNHOZ., M.G.; BREGANT, M.; MORALLES, M.; SOUZA, F.A.
  • Artigo IPEN-doc 25212
    Characterization of multilayer Thick-GEM geometries as 10B converters aiming thermal neutron detection
    2018 - LUZ, H.N. da; SOUZA, F.A.; MORALLES, M.; CARLIN, N.; OLIVEIRA, R.A.N.; BREGANT, M.; SUAIDE, A.A.P.; CHUBACI, J.F.D.; MATSUOKA, M.; SILVA, T.F.; MORO, M.V.; RODRIGUES, C.L.; MUNHOZ, M.G.
    Boron-based thermal neutron detectors have recently regained some attention from the instrumentation community as a strong alternative to helium-3 detectors. From the existing concepts exploiting boron layers in position sensitive detectors, the Cascade [1] is the one that takes full advantage of the 2D capabilities of gaseous detectors, with the position resolution not limited by the architecture of the detector. In this work, a proposal for the Cascade detector, based on Thick-GEMs is presented, together with some preliminary studies of the suitable pitch that optimizes the neutron conversion efficiency, while keeping the collection efficiency intact. The characterization of Thick-GEM prototypes produced in Brazil with hole pitch from 0.75 to 3 mm shows that these devices already present a stable performance at low gains, also resulting in fair energy resolution, when cascaded with a standard KaptonTM 50 µm GEM. Results of the first attempts of boron film depositions with Ion Beam Assisted Deposition and characterization by Ion Beam Analysis are also presented.