NATALIA FIORINI DA SILVA
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Artigo IPEN-doc 27807 Garfield++ simulation of a TH-GEM based detector for standard mammography beam dosimetry2021 - SILVA, NATALIA F.; SILVA, TIAGO F.; CASTRO, MAYSA C.; LUZ, HUGO N. da; CALDAS, LINDA V.E.The TH-GEM based detector is a robust, simple to manufacture, high-gain gaseous electron multiplier. Its operation is based on a standard printed circuit board (PCB) coated on both sides by metallic material, perforated in a millimeter pattern, and immersed in gas. In order to study the feasibility of using TH-GEM type detectors in dosimetric applications for standard mammography beams, a prototype with adequate dimensions and materials was produced. The present work encompasses the calculations of electric fields by the Gmsh and Elmer software packages and the avalanche simulation using Garfield++ library of a TH-GEM detector filled with Ar/CO2 mixture at atmospheric pressure.Artigo IPEN-doc 25078 Testing an extrapolation chamber in computed tomography standard beams2018 - CASTRO, M.C.; SILVA, N.F.; CALDAS, L.V.E.The computed tomography (CT) is responsible for the highest dose values to the patients. Therefore, the radiation doses in this procedure must be accurate. However, there is no primary standard system for this kind of radiation beam yet. In order to search for a CT primary standard, an extrapolation ionization chamber built at the Calibration Laboratory (LCI) of the Instituto de Pesquisas Energéticas e Nucleares (IPEN), was tested in this work. The results showed to be within the international recommended limits.Artigo IPEN-doc 24794 Construction of the TH-GEM detector components for metrology of low energy ionizing radiation2018 - SILVA, N.F.; SILVA, T.F.; CASTRO, M.C.; LUZ, H.N. da; CALDAS, L.V.E.The Gas Electron Multiplier (GEM) detector was originally proposed as a position sensitive detector to determine trajectories of particles prevenient from high-energy collisions. In order to study the potential of TH-GEM type detectors in dosimetric applications for low energy X-rays, specifically for the mammography standard qualities, it was proposed to construct a prototype with characteristics suitable for such use. In this work the general, structural and material parameters applicable to the necessary conditions were defined, establishing the process of construction of the components of a prototype.Artigo IPEN-doc 23115 Characterization of a free air ionization chamber for low energy X-rays2016 - SILVA, NATALIA F. DA; XAVIER, M.; VIVOLO, V.; CALDAS, L.V.E.Free air ionization chambers are used by most primary metrology laboratories as primary standards of the quantities air kerma and exposure in X-ray beams. The free air ionization chamber for low energies of the Calibration Laboratory (LCI) of IPEN showed in a characterization test a problem in the set responsible for the variation of its sensitive volume. After a modification in the support of the micrometers used for the movement of the internal cylinder and the establishment of a new alignment system protocol, the tests were redone. The objective of this work was to present the results obtained in the new condition.