GUILHERME SOARES ZAHN

GUILHERME SOARES ZAHN

(Fonte: Lattes)

Resumo

Has a bachelor's degree in Physics from Universidade de São Paulo (1991), master's at Nuclear Engineering from Universidade de São Paulo (1994) and doctorate at Nuclear Engineering from Universidade de São Paulo (2006). Has experience in nuclear ans applied physics, focusing on nuclear structure, acting on the following subjects: beta decay, neutron activation, gamma spectroscopy, nuclear structure, neutron flux determination and detection, and also on the development od instrumentation and sotware aimed at nuclear applications. (Text obtained from the Currículo Lattes on October 14th 2021)

Possui graduação em Física pela Universidade de São Paulo (1991), mestrado em Tecnologia Nuclear pela Universidade de São Paulo (1994) e doutorado em Tecnologia Nuclear pela Universidade de São Paulo (2006). Atualmente é pesquisador da Comissão Nacional de Energia Nuclear, lotado no Centro do Reator de Pesquisas do Instituto de Pesquisas Energéticas e Nucleares. Tem experiência na área de Física Nuclear, com ênfase em Estrutura Nuclear, atuando principalmente nos seguintes temas: decaimento beta, detecção de nêutrons, irradiadores de nêutrons, ativação neutrônica, fluxo de nêutrons, desenvolvimento de instrumentação e de software para aplicações nucleares. (Texto extraído do Currículo Lattes em 14 out. 2021)

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Application of a semi-empirical model for the evaluation of radium activity in phosphogypsum used as component of clinker
2021 - GERALDO, R.R.; PASCHUK, S.A.; BARRETO, R.C.; CORREA, J.N.; ZAHN, G.S.; SILVA, P.S.C. da; SILVA, A.M. da; NARLOCH, D.C.; ARAUJO, I.C.
Phosphogypsum is a residue that has been used by the cement industry as a substitute for the natural gypsum, used as a clinker additive during the production of Portland cement. There is a potential increase in this residue consumption since large amounts of phosphogypsum are generated as outcome of the phosphate fertilizer industries. However, phosphogypsum can be considered a source of radioactive contamination due to the presence of 226Ra in its composition. Depending on the concentration of 226Ra, from the radiological protection point of view, this may cause a problem because this radionuclide and its direct decay product 222Rn along with other decay products, represent the largest fraction of radiation internal dose received by people. In order to evaluate the level of radiological risk that may be associated with the use of phosphogypsum, it is necessary to identify the concentration of 226Ra in building materials. The aim of this research is to analyze samples of phosphogypsum in relation to the concentrations of 226Ra, determined indirectly through 222Rn activity measurements. This measurement process has the advantage of being fast, convenient and relatively inexpensive when compared to traditional methods of 226Ra concentration in samples measurements. The proposed physical-mathematical model was used to establish radium concentration from radon exhalation rate from cement mortar samples. The 222Rn activity measurements were performed with a portable detector with cubic phosphate samples with 50 mm edges each placed in a closed atmosphere of the sampling chamber until secular equilibrium is achieved. Obtained concentrations of radium activity in studied samples of phosphogypsum and cement mortars were found below the limits recommended by CNEN and international regulation.
Application of semi-empirical model for the evaluation of radium activity in phosphogypsum used as component of clinker
2019 - GERALDO, RICARDO R.; PASCHUK, SERGEI A.; BARRETO, RAFAEL C.; ZAHN, GUILHERME S.; SILVA, PAULO S.C. da; SILVA, AMANDA C.M.da; NARLOCH, DANIELLE C.; ARAUJO, ISABELLE C.
Phosphogypsum is a residue that has been used by the cement industry as a substitute for the natural gypsum, used as a clinker additive during the production of Portland cement. There is a potential increase in this residue use since the large amount of phosphogypsum is generated as outcome of the phosphate fertilizer industries. However, phosphogypsum can be considered a source of radioactive contamination since it has 226Ra in its composition. Depending on the concentration of 226Ra, from the radiological protection point of view, this may cause a problem because this radionuclide and its direct decay product 222Rn along with other decay products, represent the largest fraction of radiation internal dose received by people. In order to evaluate the level of radiological risk that may be associated with the use of phosphogypsum, it is necessary to identify the concentration of 226Ra in building material. The aim of this research is to analyze the samples of phosphogypsum in relation to the concentrations of 226Ra, determined indirectly through 222Rn activity measurements. This measurement process has the advantage of being fast, convenient and relatively inexpensive when compared to traditional 226Ra concentration in samples measurement methods. Proposed physical-mathematical model was used to establish radium concentration from radon exhalation rate from cement mortar samples. The 222Rn activity measurements were performed with a portable detector with cubic phosphate samples with dimensions of 50x50x50mm3 allocated in a closed atmosphere of sampling chamber until secular equilibrium was reached. Obtained concentrations of radium activity in studied samples of phosphogypsum and cement mortars were found below the limits recommended by CNEN and international regulation.
Natural and artificial nuclides in Salesópolis reservoir by gamma spectrometry
2017 - SILVA, PAULO S.C.; SEMMLER, RENATO; ZAHN, GUILHERME S.; ROCHA, FLAVIO R.; DAMATTO, SANDRA R.; FAVARO, DEBORAH I.T.