DENISE SIMÕES MOREIRA
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Artigo IPEN-doc 29835 Primary standardization and Monte Carlo modeling of ( 243Am + 239Np) by means of a 4π(PC)-γ coincidence counting system2023 - KOSKINAS, MARINA F.; MOREIRA, DENISE S.; YAMAZAKI, IONE M.; COLONNO, MARCELO; SEMMLER, RENATO; MORAIS, THALES S.L.; DIAS, MAURO S.The procedure followed by the Nuclear Metrology Laboratory (LMN) at the IPEN for the primary standardization of a ( 243Am + 239Np) solution, in secular equilibrium, is described. The measurement was carried out in a 4π(PC) (α,β)− γ coincidence system. The total activity per unit mass of the solution was determined by the extrapolation technique, using a software coincidence counting systsem. The extrapolation curves were compared with Monte Carlo calculations by means of Code ESQUEMA, used in previous works, which, was improved and applied in order to calculate the alpha, beta, gamma, X-rays and coincidence spectra.Artigo IPEN-doc 27902 Preliminary measurements using a Triple to Double Coincidence Ratio (TDCR) Liquid Scintillator Counter System2021 - KOSKINAS, M.F.; KUZNETSOVA, M.; MOREIRA, D.S.; SHOUERI, R.M.; YAMAZAKI, I.M.; MORAIS, T.S.L.; SEMMLER, R.; DIAS, M.S.The preliminary measurements using a Triple to Double Coincidence Ratio (TDCR) Liquid Scintillator Counter System, developed by the Nuclear Metrology Laboratory (LMN) at IPEN, is presented and 14C was selected to be standardized. This solution was previously calibrated by the efficiency tracing technique using a (PC)coincidence system, employing 60Co as a tracer. In order to determine the final activity, a Monte Carlo simulation was used to generate the extrapolation curve. The Software Coincidence System (SCS) developed by the LMN was used for both systems to register the events. MICELLE 2 code was used to calculate the theoretical TDCR efficiency. Measurements using HIDEX, a commercial liquid scintillator system, were also carried out and the results from the three methods were compared, showing a good agreement.Artigo IPEN-doc 27118 Primary standardization and determination of gamma ray emission intensities of Ho-1662020 - YAMAZAKI, I.M.; KOSKINAS, M.F.; MOREIRA, D.S.; SEMMLER, R.; BRANCACCIO, F.; DIAS, M.S.The procedure followed by the Nuclear Metrology Laboratory (LMN) at the IPEN-CNEN/SP, in S~ao Paulo, for the primary standardization of 166Ho is described. The activity of 166Ho was determined by the efficiency extrapolation technique applied to a 4πβ(PC)-γ coincidence system using a gas flow proportional counter in 4π geometry coupled to a 76 x 76 mm NaI(Tl) crystal. The results for the γ-rays intensities at 80.57 and 1379.45 keV were 0.0651(11) and 0.00904(11), respectively.Artigo IPEN-doc 24388 SUMCOR2018 - DIAS, M.S.; SEMMLER, R.; MOREIRA, D.S.; MENEZES, M.O. de; BARROS, L.F.; RIBEIRO, R.V.; KOSKINAS, M.F.The main features of code SUMCOR developed for cascade summing correction for volumetric sources are described. MCNP6 is used to track histories starting from individual points inside the volumetric source, for each set of cascade transitions from the radionuclide. Total and FEP efficiencies are calculated for all gamma-rays and X-rays involved in the cascade. Cascade summing correction is based on the matrix formalism developed by Semkow et al. (1990). Results are presented applying the experimental data sent to the participants of two intercomparisons organized by the ICRM-GSWG and coordinated by Dr. Marie-Cristine Lepy from the Laboratoire National Henri Becquerel (LNE-LNHB), CEA, in 2008 and 2010, respectively and compared to the other participants in the intercomparisons.