JOAO PEDRO DE OLIVEIRA FLORES

JOAO PEDRO DE OLIVEIRA FLORES

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Re-characterization of pneumatic station irradiation position of IEA-R1 reactor for use in k0 - INAA method
2024 - FLORES, J.P.O.; SEMMLER, R.; DIAS, M.S.; KOSKINAS, M.F.; MOREIRA, D.S.; YAMAZAKI, I.M.; SILVA, P.S.C.; MAIHARA, V.A.
Calibration of the short irradiation facility for k0 - NAA implementation at the IEA-R1 reactor
2021 - OLIVEIRA, J.P.; SILVA, P.S.C.; SEMMLER, R.; DIAS, M.S.; KOSKINAS, M.F.; MOREIRA, D.S.; YAMAZAKI, I.M.
The short irradiation facility of the IEA-R1 nuclear research reactor at IPEN, São 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 determine precisely the reactor parameters α and f, for implementing the k0-NAA method at the Neutron Activation Analysis Laboratory (LAN), was used the bare triple method. In this method, a set of three neutron flux monitors were irradiated without Cd-cover. The efficiency curve of the gamma-ray spectrometer used was determined by measuring calibrated radioactive sources at the commonly used counting geometries. The results for the parameters α and f were respectively 0.0384±0.0016 and 35.67±0.26. This value of f shows that the neutrons in the irradiation position are well thermalized. The variation of these parameters was studied with time and the reproducibility was verified.
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.
Characterization of neutron spectrum at the short irradiation facility of the IEA-R1 reactor using the bare triple monitor method
2017 - FLORES, J.P.O.; SEMMLER, R.
The neutron spectrum parameters were determined in the short irradiation facility of the IEA-R1 reactor of IPEN. The neutron spectrum parameters are: the epithermal neutron flux shape factor ( ) approximated by a 1=E1+ distribution and the thermal to epithermal neutron flux ratio (f ). According to the HOGDAHL formalism, the k0-NAA method uses the following input parameters: the full energy peak detection efficiency ("p), and nuclear data on Q0 (ratio of resonance integral I0 to thermal neutron cross-section 0) and k0 factors. The and f parameters depend on each irradiation facility and "p depends on each counting facility. In the HOGDAHL formalism the reactor neutron spectrum parameters ( and f ) can be obtained using three methods: Cd-ratio, Cd-covered and bare triple monitors. In this work and f were determined by the bare triple monitor method. In this method, a set of three neutron flux monitors are irradiated without Cd-cover. The efficiency curves of the gamma-ray spectrometer used were determined by measuring calibrated radioactive sources at the usually utilized counting geometries.
Caracterização do fluxo de nêutrons epitérmicos do reator IEA-R1 utilizando o método bare triple monitor para o uso em análise por ativação
2017 - FLORES, JOAO P. de O.; SEMMLER, RENATO
Caracterização do fluxo de nêutrons epitérmicos do reator IEA-R1 utilizando o método bare triple monitor para o uso em análise por ativação
2016 - FLORES, JOAO P. DE O.; SEMMLER, RENATO