MARINA FALLONE KOSKINAS

MARINA FALLONE KOSKINAS

(Fonte: Lattes)

Resumo

Graduate at Física from Pontifícia Universidade Católica de São Paulo (1972), master's at Nuclear Engineering from Universidade de São Paulo (1978) and ph.d. at Nuclear Engineering from Universidade de São Paulo (1988). Has experience in Nuclear Engineering, focusing on Instrumentation for Measure and Control of Radiation, acting on the following subjects: radionuclide metrology, standardizations in coincidence system, determination of nuclear parameters, gamma emission probability per decay. (Text obtained from the Currículo Lattes on November 17th 2021)

Possui graduação em Física pela Pontifícia Universidade Católica de São Paulo (1972), mestrado em Tecnologia Nuclear pela Universidade de São Paulo (1978) e doutorado em Tecnologia Nuclear pela Universidade de São Paulo (1988). Atualmente é pesquisador titular do Instituto de Pesquisas Energéticas e Nucleares. Tem experiência na área de Engenharia Nuclear, com ênfase em Instrumentação para Medida e Controle de Radiação, atuando principalmente nos seguintes temas: metrologia de radionuclídeos, padronização em sistemas de coincidências, determinação de parâmetros nucleares como probabilidade de emissão gama por decaimento. (Texto extraído do Currículo Lattes em 17 nov. 2021)

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Padronização primária de radionuclídeos produzidos no reator IEA-R1
2022 - KOSKINAS, MARINA F.; MOREIRA, DENISE S.; YAMAZAKI, IONE M.; BRANCACCIO, FRANCO; SEMMLER, RENATO; DIAS, MAURO S.
Neste trabalho, apresentamos uma retrospectiva dos radionuclídeos produzidos no reator IEA-R1, que foram padronizados no Laboratório de Metrologia Nuclear (LMN) do CRPq, IPEN-CNEN/SP. Para este propósito, o laboratório dispõe de sistemas de calibração primários, utilizando a técnica de coincidência 4πβ−γ, aplicando uma metodologia específica para cada radionuclídeo. Neste método, os elétrons e os raios-X são usualmente registrados por um detector 4π consistindo em um contador proporcional, cintilador plástico ou cintilador líquido. Os raios gama são registrados por meio de detectores semicondutores de HPGe ou de cristais de NaI(Tl). Neste trabalho são apresentados os diagramas eletrônicos empregados, os métodos de análise de dados e de incertezas implementados por meio da aplicação da metodologia de análise de covariância, além da aplicação de métodos computacionais de simulação dos sistemas de medida pela técnica de Monte Carlo. A padronização de radionuclídeos em sistemas absolutos tem possibilitado a determinação de parâmetros nucleares, como: probabilidade de emissão gama por decaimento e coeficientes de conversão interna, entre outros, contribuindo para a melhoria nos dados nucleares, proporcionando a formação de recursos humanos de alto nível, por meio de mestrados, doutorados e pós- -doutorados, além da participação em congressos e publicação de artigos em periódicos internacionais.
Preliminary measurements using a Triple to Double Coincidence Ratio (TDCR) Liquid Scintillator Counter System
2021 - 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.
Primary standardization and determination of gamma ray emission intensities of Ho-166
2020 - 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.
Standartization of (166m)Ho in a coincidence system by software and determination of its gamma emission probabilities
2019 - CARVALHO, ANA C.R. de; MOREIRA, DENISE S.; KOSKINAS, MARINA F.; DIAS, MAURO da S.
This works presents a new standardization of the radionuclide (166m)Ho that was carried out at Nuclear Metrology Laboratory (LMN) at IPEN. (166m)Ho decays with 1133 years of half-life by beta emission followed by a cascade of gamma-rays in a range of 73 to 1427 keV, and these characteristics makes it a good secondary standard to the calibration of gamma spectrometers. Previously calibrated with a standard 4 Pi(PC)Beta-Gama coincidence system, the same samples were now measured in the Software Coincidence System (SCS), where the data analyses can be done after the measurements, using a software developed at LMN as well. The SCS is composed of a 4Pi geometry proportional counter operated at 0.1MPa coupled to one NaI(Tl) crystal, positioned above the PC counter, and to a HPGe detector, positioned below the PC counter. The signals from all detectors are digitalized and their pulses height and time of occurrence are recorded on computer files. After the standardization, the emission probabilities per decay of the most intense gamma-rays in the (166m)Ho decay were determined by means of a HPGe spectrometer system, which was calibrated with standard sources previously calibrated in the 4 Pi(PC)Beta-Gama coincidence system, and the results were compared with the literature. All the uncertainties were treated by the covariance analysis method.
Preliminary study of radionuclide standardization by TDCR method applying a time-to-amplitude converter
2019 - MORAIS, THALES S.L. de; KOSKINAS, MARINA F.; MOREIRA, DENISE S.; DIAS, MAURO da S.
This paper proposes an alternative to the use of counters for the standardization of radionuclides in a 3-photodetectors liquid scintillation counter by the triple to double coincidence ratio (TDCR) method using an electronic system for processing pulses that allows the subtraction of the accidental coincidences. The electronic system consists of ampli ers, discriminators, logic gates and delay modules feeding a time-to-amplitude converter (TAC) with output to a multichannel analyzer (MCA). This system does not require individual counters for each photodetector and coincident counts contribute to the noise reduction. The method compares 3 di erent TAC spectra registered in MCA with 4, 3 or 2 peaks obtained from di erent con gurations of the electronic system. For testing the system, a series of measurements with a 90Sr standard solution was performed.
Preliminary measurements using a Triple to Double Coincidence Ratio (TDCR) Liquid Scintillator Counter System
2019 - KOSKINAS, MARINA F.; KUZNETSOVA, MARIA; MOREIRA, DENISE S.; SCHOUERI, ROBERTO M.; MORAIS, THALES S.L. de; SEMMLER, RENATO; DIAS, MAURO da 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. The TDCR system makes use of three photomultipliers positioned at 120° relative angle, operating in coincidence. For this preliminary measurement, 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. 14C was chosen due to be a beta pure emitter with low end-point energy of 156 keV. 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.
Data analysis software package for radionuclide standardization with a digital coincidence counting system
2020 - BRANCACCIO, F.; DIAS, M.S.; KOSKINAS, M.F.; MOREIRA, D.S.; TOLEDO, F. de
The Nuclear Metrology Laboratory (LMN) – IPEN, S~ao Paulo, Brazil – developed a Digital Coincidence System (DCS), based on the Coincidence Counting Methodology, in order to improve its capabilities in radionuclide primary-standardization. Digital process is implemented in two steps: data-acquisition (a set of measurements) and offline software data-analysis and calculation. The present work shows the basics of the data-acquisition unit (Software Coincidence System – SCS), describes the DCS’ data-analysis process and the initial approaches chosen for the implementation of the software package (Coincidence Analyzing Task – CAT). 152Eu standardization, performed for DCS testing, software expansion and validation, is briefly discussed.
Standardization of 32P radioactive solution
2017 - MARQUES, C.P.; KOSKINAS, M.F.; ALMEIDA, J.S.; YAMAZAKI, I.M.; DIAS, M.S.
The standardization solution using three different methods is presented. The disintegration rate was determined by the CIEMAT/NIST and TDCR methods in liquid scintillator systems and self-absorption extrapolation method using 4(PC)- system. The results obtained for the activity of the 32P solution were compared and they agree within experi- mental uncertainties.
Disintegration rate and gamma-ray emission probability per decay measurement of Cu-64
2017 - KOSKINAS, M.F.; YAMAZAKI, I.M.; MOREIRA, D.S.; TAKEDA, M.N.; DIAS, M.S.
This work aims to present the 64Cu standardization method developed in the Nuclear Metrology Laboratory (LMN) at the IPEN-CNEN/SP, using a 4 􀀀 coincidence system, and the measurement of the gamma-ray emission probabilities per decay of 1345.7 keV of 64Cu by means of a REGe gamma-ray spectrometer. The 4 􀀀 coincidence system consists of a gas- flow proportional counter with 4 geometry and using 90% Ar + 10% CH4 gas at 0.1 MPa, as the detector, coupled to two NaI(Tl) crystal for the gamma-ray emission detection. The events were registered by means of a Time to Amplitude Converter (TAC) associated with a Multi-Channel Analyzer. Two gamma-ray windows were set for the coincidence measurements, one including the positron-annihilation quanta and the other located at the total absorption energy peak of the 1345.7 keV gamma-ray transition. The 64Cu was obtained by irradiating 0.3mg of metallic cooper in the IEA-R1 research reactor under a 1 1013 cm􀀀2 s􀀀1 thermal neutrons flux. To obtain the 64Cu solution the foil irradiated was dissolved in 20 L of HNO3 65% and after that was diluted in 20 mL of 0.1M HCl. The activity was determined by means of the extrapolation curve from eight irradiations, normalized by means of the germanium measurements. The Kawada factor to correct the inefficiency for beta plus and beta minus in the N4 has been applied. The gamma-ray full efficiency peak curve of the germanium spectrometer was measured at 17.9 cm of source-detector distance, in the energy range from 244 keV to 2754 keV, by measuring flamed-sealed ampoules of 24Na, 60Co, 133Ba, 137Cs, and 152Eu standardized at the LMN. The sample for measurement in the spectrometer was prepared in flame-sealed ampoule with 1 mL of the diluted solution. The gamma-ray emission probability per decay of the 1345.7 keV transition of 64 Cu was (0.472 0.010)%, in agreement with the literature.
Disintegration rate and gamma-ray emission probability per decay measurement of Cu-64
2018 - YAMAZAKI, I.M.; KOSKINAS, M.F.; MOREIRA, D.S.; TAKEDA, M.N.; DIAS, M.S.
The procedure followed by the Nuclear Metrology Laboratory (LMN) at the IPEN for the standardization of activity of 64Cu is described. The measurement was carried out in a 4π (PC) β-γ coincidence system. The activity per unit mass of the solution was determined by the extrapolation technique. The events were registered using a Time to Amplitude Converter (TAC) associated with a Multi-channel Analyzer. The gamma-ray emission probability per decay of the 1345.7 keV transition of 64Cu determined with a calibrated REGe gamma-ray spectrometer was (0.472±0.010) %, in agreement with the literature.