NATALIA FIORINI DA SILVA

NATALIA FIORINI DA SILVA

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Evaluation of an extrapolation chamber for dosimetry in computed tomography beams using Monte Carlo code (MCNP5)
2020 - CASTRO, MAYSA C.; SILVA, NATALIA F.; SANTOS, LUCAS R.; CINTRA, FELIPE B.; CALDAS, LINDA V.E.
Computed tomography (CT) is responsible for the highest dose values to the patients during the exams. Therefore, the radiation doses in this procedure must be accurate. However, there is no primary standard system for this kind of radiation beam yet. A homemade extrapolation ionization chamber was preliminary evaluated for the establishment of a CT beam primary standard. The aim of this study was to determine the influence that the various components of the extrapolation chamber may present on the energy deposited in its sensitive volume. Different materials for its collecting electrode were also studied for this type of radiation beam. The evaluation of the homemade extrapolation chamber showed the highest influence of 25.9% for the collecting electrode, and the best material for the collecting electrode for CT radiation beams was graphite.
Simulation of a TH-GEM based detector for standard mammography-quality beam dosimetry using the MCNP5 code
2019 - SILVA, N.F.; SILVA, T.F.; CASTRO, M.C.; LUZ, H.N. da; CINTRA, F.B.; CALDAS, L.V.E.
Simulation of geometry and materials of the TH-GEM based detector for radiation dosimetry
2018 - SILVA, NATALIA F.; SILVA, TIAGO F.; CASTRO, MAYSA C.; LUZ, HUGO N. da; CINTRA, FELIPE B.; CALDAS, LINDA V.E.
Evaluation of an extrapolation chamber for dosimetry in computed tomography beams using Monte Carlo code (MCNP5)
2018 - CASTRO, MAYSA C.; SILVA, NATALIA F.; SANTOS, LUCAS R.; CINTRA, FELIPE B.; CALDAS, LINDA V.E.
Evaluation of the influence of the TH-GEM detector components in dosimetric measurements of standard mammography beams
2017 - SILVA, NATALIA F.; SILVA, TIAGO F.; CASTRO, MAYSA C.; CINTRA, FELIPE B.; LUZ, HUGO N. da; CALDAS, LINDA V.E.
GEM detectors have found applications in many areas due to their simplicity of construction, low cost, ruggedness and diversity of shape. A dosimeter with these qualities presents utility in several applications, as for example in diagnostic and therapeutic medicine, industrial radiography and nuclear meters. Furthermore, the high sensitivity provided by GEM detectors may extend their applications in low dose dosimetry. Based on these facts, it may be interesting to produce a prototype of a portable TH-GEM type detector with characteristics suitable for dosimetric use in X-rays with low and medium energies. The precise determination of the dosimeter characteristics is very important for laboratories of instrument calibration, as well as to determine how the various components of the detector may influence on the energy deposited in the sensitive volume. In this work, the results obtained about the influence of each one of the components present in this type of detector in standard mammography beams is presented. The code MCNP5 was used. The results allowed the adaptation of the detector to the desired conditions.
Determinação do fator de correção para atenuação no ar para uma câmara de ionização de ar livre
2016 - SILVA, NATALIA F.; CINTRA, FELIPE B.; CASTRO, MAYSA C. de; CALDAS, LINDA V.E.
Este trabalho tem como objetivo apresentar os resultados obtidos experimentalmente e por simulação para o fator de correção da atenuação no ar de uma câmara de ionização de ar livre de cilindros concêntricos Victoreen, modelo 481- 5. Este fator de correção foi obtido para as qualidades padronizadas de mamografia, estabelecidas no Laboratório de Calibração de Instrumentos (LCI) do IPEN. Os valores obtidos foram comparados com os resultados do laboratório padrão primário alemão Physikalisch-Technische Bundesanstalt (PTB), obtendo-se diferenças máximas de 0,40% para o valor experimental e de 0,31% para o valor simulado.