RENATO SEMMLER

RENATO SEMMLER

(Fonte: Lattes)

Resumo

Graduado em Física pela Pontifícia Universidade Católica de São Paulo (1989), Mestre em Tecnologia Nuclear pela Universidade de São Paulo (1993) e Doutor em Tecnologia Nuclear pela Universidade de São Paulo (2006). Atualmente é pesquisador da Comissão Nacional de Energia Nuclear (CNEN), lotado no Centro do Reator de Pesquisas (CERPq) do Instituto de Pesquisas Energéticas e Nucleares (IPEN). Docente da pós-graduação stricto sensu - Programa de tecnologia nuclear do IPEN - Universidade de São Paulo e da pós-graduação stricto sensu - Mestrado profissional de tecnologia das radiações na saúde. Tem experiência na área de Física Nuclear de baixas energias atuando nos seguintes temas: reações de captura de nêutrons térmicos (prompt gamma rays), método k0 de análise por ativação neutrônica, caracterização do espectro de nêutrons junto aos canais de irradiação do reator IEA-R1, espectroscopia gama, fotodesintegração, reações fotonucleares (fotofissão e fotonêutrons) e ensino de física. Professor e organizador da EAEN - Escola Avançada de Energia Nuclear para estudantes do Ensino Médio, preferencialmente envolvidos com olimpíadas de física e química: Teoria e Aplicações das Ciências Nucleares. Professor de física com mais de 25 anos de experiência em cursos universitários, pré-vestibular e ensino médio. (Texto extraído do Currículo Lattes em 27 dez. 2021)

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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.
Development of a semantic layer for a data repository prototype for neutron activation analysis domain data
2019 - CARVALHO, GLAUBER M. de; SEMMLER, RENATO; MENEZES, MARIO O. de
In order to provide greater transparency for scienti c research and the results achieved, a great e ort is ongoing to make available scienti c data repositories, which allow for di erent researchers to validate, reproduce and reuse third party scienti c data. With the always increasing use of technology in all kinds of scienti c facilities, a growing amount of data is collected even from simple experiments. This scenario presents a new paradigm: the understanding of third party data easily found on data repositories. Consequently, being able to do useful searches on these data repositories poses a new challenge for traditional search engines. In this work, the approach taken to help solve these problems was to propose a semantic layer for scienti c data repository. By using ontologies, with appropriated integration of traditional search mechanisms, it will be easier for users to nd related data that could be used in their work, improving the overall scienti c yield. In order to achieve this goal, a ontology was developed, using the Prot eg e software, for the Neutron Activation Analysis (NAA) data domain. This ontology was validated by experts from NAA Laboratory of the Reactor Research Center (CERPq) at the Nuclear and Energy Research Institute (IPEN-CNEN/SP). A prototype of a semantic data repository is, thus, being developed using the Django web development framework. RDFlib, a software library written in Python is being used to allow the integration of semantic operations, based on the NAA ontology, with the relational database layer provided by Django.
Development of a web free software for the absolute efficiency calibration for HPGe type detectors
2019 - KAISER, THIAGO J.S.; SEMMLER, RENATO; LIMA, GEAN B. de
The IEA-R1, swimming pool research reactor, from the Institute of Energy and Nuclear Research (IPEN), among other uses, the instrumental neutron activation analysis technique is widely used, and successfully, by the Neutron Activation Laboratory (LAN), using the comparative method. In this method a sample is irradiated simultaneously with a standard. In order to overcome the difficulty of a multi -elementary analysis, because it was necessary to prepare several standards, the k0 method of neutron activation was developed. In method k, the concentration of sample elements is calculated in relation to a comparator element, generally gold. However, for the use of the k0 method, it is necessary to accurately determine the detection efficiency in the energy range of interest and the geometry of the experimental arrangement. In order to circumvent the manual processing of the data in spreadsheets, which could be affected by errors, a free code web software was developed for calibration in absolute efficiency of an HPGe type detector for neutron activation analysis based on the k0. We used the free, low learning curve standardized Python programming language in the eScience project, which is part of the software, and the Django web framework with a simple and intuitive interface. In the system it is possible to register the detectors, radioactive sources and their manufacturers, projects and spectra, attributes necessary to calculate the absolute efficiency of an HPGe type detector. In addition to calculating efficiency, the system plots the graph with the efficiency points, trend curve, with possibility of adjustments, and error bar representing the uncertainties. The system issues reports on spectra and efficiency data for each project. The reports make it possible to check the data as well as its use in other applications. Because it is a web software, its access is allowed from any device with an internet connection. Another result obtained with the system is the reduction of the possibility of errors with the manual treatment of the data in spreadsheets.
Determination of k0 and Q0 for 74Se, 113In, 186W and 191Ir targets applying covariance analysis
2019 - BARROS, L.F.; RIBEIRO, R.V.; DIAS, M.S.; MORALLES, M.; SEMMLER, R.; YAMAZAKI, I.M.; KOSKINAS, M.F.
In the present work, the determinations of k0 and Q0 for 74Se, 113In, 186W and 191Ir targets were performed. The irradiations were conducted near the core of the IEA-R1 4.5MW swimming-pool nuclear research reactor of the Instituto de Pesquisas Energéticas e Nucleares (IPEN-CNEN/SP – Nuclear and Energy Research Institute), in São Paulo, Brazil. The irradiation position was chosen where the neutron spectrum shape parameter α is very close to zero. For this reason, the correction to be applied for the determination of Q0 is very close to one, thus improving the accuracy of the results. For each experiment, two irradiations were carried out in sequence: the first one with bare samples and the second with a cadmium cover around the samples. All partial uncertainties were considered, applying the covariance matrix methodology. The final results were compared with the literature.
Calibration of the short irradiation facility for K0 − NAA implementation at the IEA-R1 Reactor
2019 - OLIVEIRA, J.P.; SILVA, P.S.C.; SEMMLER, R.
The short irradiation facility of the IEA-R1 nuclear research reactor at IPEN, S~ao Paulo, Brazil, has been used for short irradiation of samples for the purpose of determining the concentration of elements of these samples through the use of the instrumental neutron activation analysis technique. With the aim of implementing the k0-NAA method at the Neutron Activation Analysis Laboratory (LAN), the reactor parameters and f were obtained using the bare triple method. In this method, a set of three neutron ux monitors were irradiated without Cd-cover. The e ciency curve of the gamma-ray spectrometer used were determined by measuring calibrated radioactive sources at the usually utilized counting geometries. The results obtained for the parameters and f were respectively 0:0384 0:0016 and 35:67 0:26. The obtained value of f shows that the neutrons in the irradiation position are well thermalized, in other words, the value of f, means that thermal neutron ux is 35 times higher than epithermal neutron ux. It means that this irradiation position is well thermalized. The variation of these parameters was studied with time and the reproducibility was veri ed.
Repositório semântico de dados de análise por ativação neutrônica
2018 - CARVALHO, GLAUBER M. de; SEMMLER, RENATO; MENEZES, MARIO O. de
Scientific Data Repositories are being made available each time more often, in a search for more transparency for scientific research and its results, making, in this way, possible to validate, reproduce and reuse the data in other studies. In this work, we present the ongoing research, part of a master dissertation, being developed at IPEN-CNEN/SP, seeking to build a semantic repository for Neutron Activation Analysis research data. The study began with the ontology construction and some of the preliminar results of this phase are presented.
Natural and artificial nuclides in Salesópolis reservoir
2019 - SILVA, P.S.C.; SEMMLER, R.; ZAHN, G.S.; ROCHA, F.R.; DAMATTO, S.R.; FAVARO, D.I.T.
Natural radioactivity is ubiquitous in the environment mainly due to the presence of the nuclides from the ura-nium and thorium series and 40K. Although in the South Hemisphere nuclear tests have been fewer in number than that in the North, artificial radionuclides can also be found spread at ground level. In this study, the activity concentrations of natural nuclides from the uranium and thorium series, 40K and the artificial 137Cs were deter-mined in a sediment core with 42 cm depth collected in the middle of the Salesópolis reservoir, located in the Metropolitan Region of São Paulo city (SPMR). The Usina Parque Rio Tietê reservoir belongs to the Alto do Tietê system for the capture, storage and treatment of water for SPMR. Therefore, the quality of the water and sediments of this dam is of great importance. The activity concentrations were measured by gamma spectrome-try. Samples were measured and saved at regular intervals at a maximum of 160 000 seconds. The gross area were determined for each peak and plotted against time and the counting rate was obtained by the slope of the curve. Background and reference materials were also counted and treated in the same way. Results showed that 226Ra varied from 45 to 116 Bq kg-1; 228Ra, from 80 to 165 Bq kg-1; 40K, from 155 to 1 187 Bq kg-1 and 137Cs varied from 0.3 to 7 Bq kg-1. The methodology applied for determining low levels of 137Cs in sediment proved to be effi-cient and reproducible.
SUMCOR
2018 - 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.
Natural and artificial nuclides in Salesópolis reservoir by gamma spectometry
2017 - SILVA, P.S.C.; SEMMLER, R.; ZAHN, G.; ROCHA, F.R.; DAMATTO, S.R.; FAVARO, D.I.T.
Natural radioactivity is ubiquitous in the environment mainly due to the presence of the nuclides from the uranium and thorium series and K-40 in soil, water and sediments. Although in the South Hemisphere nuclear tests have been fewer in number than that in the North, artificial radionuclides can also be found spread at ground level. Salesópolis is located in the Metropolitan Region of São Paulo city (SPMR). The Usina Parque Rio Tietê (Salesópolis) reservoir belong to the Alto do Tietê system for the capture, storage and treatment of water for the São Paulo Metropolitan Region (SPMR). Therefore, the quality of the water, as well as, of sediments of this dam is of great importance. In this study, the activity concentrations of the natural uranium and thorium nuclides series, K-40 and the artificial Cs-137 were determined in a sediment core (T1B) with 42cm depth and sliced each 3 cm totalizing 14 samples, collected in the middle of the Salesópolis dam. Samples were sealed and wait 30 days for the radioactive equilibrium to be reached. The activity concentrations were measured by gamma spectrometry. Samples were counted and saved at regular intervals at a maximum of 160 000 seconds. The gross area were calculated for each peak and plotted against time and the counting rate was obtained by the sloop of the curve. The background and reference materials were treated in the same way. Results showed that 228Th varied from 44 to 150 Bq kg􀀀1 ; 228Ra, from 49 to 149 Bq kg􀀀1; 226Ra, from 26 to 88 Bq kg􀀀1; 210Pb, from 93 to 247 Bq kg􀀀1 ; 40K, from 127 to 852 Bq kg􀀀1 and 137Cs varied from 0.2 to 6.7 Bq kg􀀀1
E-science, data science and scientific computing
2017 - MENEZES, M.O.; SEMMLER, R.; CARVALHO, G.M. de; LANDULFO, E.; DIAS, M.S.
The publication of papers in scientific journals or conference proceedings, has being the main way of summarization of experimental results obtained by the researchers over the time. However, the sharing of the experimental data in raw format or after some processing, is also equally important for the scientific community, as they provide the necessary input to reproducible experiments and also to independent validation of scientific results. Nowadays, the volume of scientific data production has increased to giant amounts, demanding new means of storage and curation as well as processes and technologies to make them available in durable ways. As a consequence, and at the same time a response, to those demands, a new scientific paradigm has emerged: the e-Science. This new paradigm distinguished itself from the traditional science, being characterized by intense computational activity, required to process the large volume of data that can be obtained from modern scientific experiments. e-Science, ultimately, is related to knowledge discovery and sharing not only as scientific publications, but also as experimental data, rich theoretic vocabularies, and several reusable services useful to the scientific community. The great availability of scientific data, both in raw or processed formats, leveraged by the adoption of transparency and accessibility politics by scientists all over the globe which publish their data on institutional or private repositories, are making possible also the reutilization of such data for new analysis by other scientists, who, employing new statistical approaches, such as machine learning algorithms suited to large amount of data, are also obtaining new results, not only from old data, but also, from the big amount of data originated from modern experimental facilities, doing what is known as "data science". The demand for intense computational utilization by e-Science related activities include not only the traditional simulation methods, but also the development of new tools that can operate in these new environments, such as, cloud based storage, cloud based access and analysis, mobile access to their research data, equipment monitoring and management, etc. All these activities are the scope of Scientific Computing being conducted at the Research Reactor Center - CRPq (IPEN-CNEN/SP).