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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Primary standardization and Monte Carlo modeling of ( 243Am + 239Np) by means of a 4π(PC)-γ coincidence counting system
2023 - 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.
k0‑IPEN
2023 - DIAS, MAURO da S.; SEMMLER, RENATO; KOSKINAS, MARINA F.; MOREIRA, DENISE S.; YAMAZAKI, IONE M.; BRANCACCIO, FRANCO; BARROS, LIVIA F.; RIBEIRO, RAFAEL V.; MORAIS, THALES S.L. de
A software package for INAA (Instrumental Neutron Activation Analysis), developed at the Nuclear Metrology Laboratory of the IPEN-CNEN/SP, called k0-IPEN, is described. The package consists of a main program linked to nine subprograms designed to perform automatically most of the tasks necessary in order to obtain the mass fractions of the irradiated samples. External efficiency curves calculated by the Monte Carlo code MCNP6 can be read to extend the calibration curve to source to detector distances where only a few experimental points are available. Covariance analysis was used in all steps of the calculation. The validation of the code was tested in an intercomparison sponsored by the IAEA.
k0-IPEN
2022 - DIAS, MAURO da S.; SEMMLER, RENATO; KOSKINAS, MARINA F.; MOREIRA, DENISE S.; YAMAZAKI, IONE M.; BRANCACCIO, FRANCO; BARROS, LIVIA F.; RIBEIRO, RAFAEL V.; MORAIS, THALES S.L. de
A new software package for INAA, developed at the Nuclear Metrology Laboratory (LMN) of the Nuclear and Energy Research Institute (IPEN-CNEN/SP), called k0-IPEN, is described. The package consists of a main program linked to nine subprograms designed to perform automatically all the tasks necessary in order to obtain the mass fractions of the irradiated samples. The goals of these nine routines are: a) to calculate the experimental peak efficiencies and P/T ratios for the standard sources, together with all the corresponding uncertainties; b) to correct the peak efficiencies for coincidence summing; c) to fit the peak efficiencies and P/T ratios with log-log polynomial functions; d) to determine experimentally the  and f parameters by the Triple Bare and by the Cd Ratio Multimonitor Methods; e) to correct for interferences; f) to determine the average mass fractions, taking into account the correlations among all partial uncertainties involved. In the present version, the only data that must be inserted as input parameter, externally from the package, are the self-shielding correction factor, which is calculated by the MATSSF code, and the geometry factor that corrects for the difference between sizes of standard sources and measured samples. The code can deal with different spectrum formats such as CHN, SPE and CNF. The routine designed to calculate the peak areas has a simple algorithm and is not yet capable of separating multiplets. Therefore, it is suitable for analysing separated peaks, such as those found in standard calibration source measurements. However, for complex spectra, the code can read peak list files obtained from other codes, such as HyperMet or HyperLab. External efficiency curves calculated by the Monte Carlo code MCNP6 can be read to extend the calibration curve to regions where there are only a few experimental points available. The code k0-IPEN is being tested and its validation accomplished by means of an intercomparison sponsored by the IAEA, and presented at this conference.
Experimental determination of k0 and Q0 values for 121Sb, 123Sb and 130Ba targets applying covariance analysis
2022 - BARROS, L.F.; DIAS, M.S.; KOSKINAS, M.F.
This work consists of an experimental determination of k0 and Q0 for 121Sb, 123Sb and 130Ba targets. Covariance analysis has been introduced to supply not only the overall uncertainties in these parameters but also their correlations. The irradiations were performed near the core of the IEA-R1 4.5 MW swimming-pool nuclear research reactor of the Nuclear and Energy Research Institute (IPEN-CNEN/SP), in São Paulo, Brazil. The epithermal neutron flux shape parameter, alpha, at the irradiation position is very close to zero, which favors to obtain Q0 values more accurately. Two irradiations were carried out in sequence, using two sets of samples: the first with bare samples and the second inside a Cd cover. The activity measurements were carried out in a previously calibrated HPGe gamma-ray spectrometer. The measurements were corrected for: saturation, decay time, cascade summing, geometry, self-attenuation, measuring time and mass. Standard sources of 152Eu, 133Ba, 60Co and 137Cs traceable to a 4πβ−γ primary system were used to obtain the HPGe gamma-ray peak efficiency as a function of the energy. The experimental efficiency curve was performed by a fourth-degree polynomial fit, in the energy range of the standard sources, 121–1408 keV, it contains all correlations between points. For energies above 1408 keV, the efficiencies were obtained by the Monte Carlo Method. The covariance matrix methodology was applied to all uncertainties involved. The final values for k0 and Q0 were compared with the literature.
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.
Standardization of 59Fe by 4π(PC)β-γ software coincidence system
2015 - KOSKINAS, M.F.; YAMAZAKI, I.M.; DIAS, M.S.
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.
Experimental and theoretical cross sections for K-shell ionization of 52Te, 73Ta, and 83Bi by electrons with energies up to 100 keV
2019 - SANTOS, O.C.B.; VANIN, V.R.; MAIDANA, N.L.; MARTINS, M.N.; TABACNIKS, M.H.; RODRIGUES, C.L.; SILVA, T.F.; SANTOS, A.D.; BARROS, S.F.; GARCIA-ALVAREZ, J.A.; KOSKINAS, M.F.; FERNANDEZ-VAREA, J.M.; PINDZOLA, M.S.
In this work we present a combined experimental and theoretical study of K-shell ionization by electrons with energies close to the threshold. The ionization cross sections of the K shells of Te, Ta, and Bi atoms have been measured up to 100 keV with uncertainties ranging from 4% to 8%. In turn, calculations have been done using the subconfiguration average distorted-wave (SCADW) method, which includes the full two-body retarded electromagnetic interaction between the projectile and target electrons. The predictions of the SCADW method are in good agreement with the experimental data. In contrast, theoretical cross sections based on first-order perturbation theory where the transverse interaction is computed with plane waves instead of distorted waves underestimate the SCADW values as well as the experimental data. The difference between the two investigated ab initio formalisms grows with atomic number, being 3% for Te, 15% for Ta, and 25% for Bi. An additional comparison of both theoretical approaches with recent measurements for Au K supports the conclusion that the SCADW method reproduces well the experimental K-shell ionization cross section of atoms with intermediate to large Z near the threshold.